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Continue Continue Exit Filter FINISH finish Definition definition Glossary Terms Menu Please rotate your device NEXT next Notes Notes Bio More info Captions pause play Send an email PREV previous Question List replay Additional Resources resources Restart Resume Search... search Search in: Search Results Back to top Slide Text SUBMIT ALL submit all SUBMIT submit volume a guide of symbols used in this course key terms learner activity questions additional resources process safety hazard controlthis element focuses on the purpose and requirements of operating procedures and explores the hazards and risks associated with different components of the process industries. element 3 learning outcomes at the end of the training, you will be able to: 3.1. explain the purpose and requirements of standard operating procedures3.2. outline the controls that should be adopted to control the safe start-up and shut-down of process plant3.3. outline the necessity for performance standards for safety critical systems and equipment and the concept of ‘farsi’ 3.4. outline the hazards and controls associated with the use of steam and water within the process industries learning outcomes (continued) at the end of the training, you will be able to: 3.5. outline the hazards and controls associated with electricity / static electricity within the process industries3.6. outline the physical forms of dangerous substances and how these can determine process risk3.7. outline the hazards presented by chemical reactions and the protective measures used to mitigate the consequences of a thermal runaway reaction3.8. outline the hazards and controls available for the bulk storage of dangerous substances. 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances. 3.5 electricity/static electricity. 3.7 reaction hazards 3.8 bulk storage operations element 3: process safety hazard control safe operating envelope (soe) defines boundaries of a controlled reaction. the optimised conditions which keep the process under control. operating outside this ‘envelope’ is unsafe. typical parameters used to define boundary: pressure; temperature; flow rate. learn more about the designing and operating safe chemical reaction processes hsg 143 on this page. what parameters might define the soe? example1 diammonium phosphate (dap) example 2 what parameters might define the soe? purpose of standard operating procedures (sops) inform operator about the process safety hazards. describe the control system. describe standard operating conditions (including allowable range/excursions). what is the connection with soe? answer: sops help keep the process within the soe. key terms safety instrumentation system (sis) the system for connections and equipment that operates automatically the process controls, for example valves that maintain the process in the soe. proportional-integral derivative (pid) three separate elements (proportional, integral and derivative) which comprise the control loop that regulates the process variables, eg, pressure. this avoids the need to have manually operated process control. types of sops start-up/shut-down. plant and equipment maintenance and modifications / changes. responding to alarms tripping and emergencies. filling/emptying/charging of vessels, pipelines and reactors. responding to unplanned deviations and ‘abnormal operations’. who is involved in developing sops? operators. maintenance team contractors design/ engineering team. the initial writing and development of any sop requires input from the designer/engineer and also the operator(s); in other words, the stakeholders involved with that part of the process to which the procedure relates. this latter is to ensure that the procedure actually matches what is done. activity what are the reasons for involving operators in the writing of procedures? think about this and complete the activity on the next slide before progressing. learner activity close close close close close close correct to ensure the procedure matches what is done. involving operators increases acceptance & following of procedures. it creates a sense of ownership. to reduce the workload of supervisors. writing procedures is a responsibility of operators. to shift the responsibility to operators if errors occurring. match the statements to the correct heading and press ‘submit’ when finished. incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct to ensure the procedure matches what is done. involving operators increases acceptance & following of procedures. it creates a sense of ownership. to reduce the workload of supervisors. writing procedures is a responsibility of operators. to shift the responsibility to operators if errors occurring. match the statements to the correct heading and press ‘submit’ when finished. submit submit submit submit submit submit reasons for involving operators in the writing of sops to ensure the procedure matches what is done. involving operators increases acceptance and following of procedures. it creates a sense of ownership. it reduces the likelihood for errors occurring. nb - not every relevant operator will be able to participate in the drafting as there is a limitation of the effectiveness of individual performance. involving operators what should be included within sops? purpose of the operation/process. plant/equipment/materials being used. process steps – who, what, where, how, why. hazards and risks: controls required and order in which applied. pictures, photos, drawings, flowcharts, checklists. authorisation of workers to undertake procedure. ppe requirements. availability/accessibility of spare parts, together with the necessary standard. requirements for procedures to be clearly understood draft, trial and revise the procedure until it’s clear and easily followed. include operators in the drafting. involve someone not familiar with the procedure to demonstrate it can be followed. explain not only ‘what’ and ‘how’, but also ‘why’. when procedures aren’t fully understood, disasters can happen. watch the video about the incident at the west fertiliser company in texas. video ensuring sops remain current and accurate report and analyse all deviations from the expected process parameters. undertake programmed reviews and oversight of actual practice (observation or retrospective analysis, eg quality of end product). careful checking and monitoring of the sis (linked to risk-based inspection). review of moc reports, inspection records and reports. review frequency of maintenance on safety-critical plant and equipment variations are indicative of potential loss of the safety envelope. they can be detected by: assessment of defect complaints; product out of specification; reports on deviations in the process; variations in yield; feedstock raw material records; adverse event reports. ensuring sops remain current and accurate limitations of sops factors that affect operators to follow sop time pressure. workload. staffing levels. training. supervision. human fallibility. technical issues. consequences of deviating from operating procedures organisational ‘drift’. major disaster for both operators, plant and the organisation’s reputation. importance of responding to alarms example of three mile island operators took 2.5 hrs to understand the problem texas city – tired and poorly trained operators essential that operators are trained, confident and well-rehearsed in the required actions to take in the event of an alarm activating should reduce unplanned downtime, increase levels of process safety, improve operator effectiveness and produce better process performance 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances. 3.5 electricity/static electricity. 3.7 reaction hazards 3.8 bulk storage operations element 3: process safety hazard control types of start-up and shut-down planned start-up and shut-down (‘turnaround’) follow a pre-determined sequence. planned shut-down: when plant is closed for periodical maintenance/replacements. planning done well in advance (months). risk assessment. linked to product supply and assessment of plant requirements. unplanned shut-down is unexpected, eg equipment malfunction, power failure, operator error. may be partial or complete. the absence of a plan makes it more dangerous. the nature for the require shut-down will have a direct impact on the issues to be addressed. often involves only part of a plant. emergency no pre-shut-down review. when a hazardous situation develops, usually as a result of a breach in the safe operating envelope (out of normal scope). human factor plays a paramount role. no stages, difficult to use checklists. very high risk. done in stages, eg some parts of a large plant may take several days to shut down. start-ups: progressive process implementation. all planned shut-downs are generally staged to prevent impact on operations. staged activity why do you think both start-up and shut-down are potentially dangerous processes? think about this and complete the activity on the next slide before progressing. learner activity complete close close close close close close click the icon below to download your reflection as a document file and save this for your own records. download download download download download download why do you think both start-up and shut-downare potentially dangerous processes? type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> learner activity sample answer: plant and process controls may be turned off or adjusted for the shut-down. never really know the full status of the process/plant. may not be able to plan for every contingency. plant and process needs to be restored to its steady state and this will require variations from normal operating status. pre-start-up safety review a pre-start-up safety review to confirm: that any modifications meet appropriate management of change requirements post pressure testing, plant has been suitably drained and/or dried of contaminants blanks removed and drain valves, sample points and relevant vents closed ready for service visual inspection of plant to determine that all work has been completed all alarms, trips and prv’s are in working order when required, ie, new plant or changes, full training given to relevant workers/contractors pre-start-up safety review factors to consider moc. pressure testing and gauge control setting. safety systems all operational. mechanical preparation. chemical cleaning instructions. physical cleaning instructions. mechanical restoration. machinery run-in. tightness testing. pre-start-up safety review electrical testing/functional tests/energising. operation and calibration of alarms and rvs. instruments calibration and functional test. loading of chemicals. loading of catalyst. heaters drying. chemicals boil out of steam generation facilities. alarms assist the operator to identify abnormal, hazardous and unsafe plant and process conditions. operators must be able to identify, understand and respond to alarms appropriately. consider: do they require an operator response? how are they presented to the operator? plant shut-down communications. testing/checking of safety and operational controls (emergency blowdown, esdvs, prvs, trips, alarms). checking of plugs and blinds. checking structural and physical connections. 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances. 3.5 electricity/static electricity. 3.7 reaction hazards. 3.8 bulk storage operations. element 3: process safety hazard control activity what is a ‘performance standard’ for a safety critical system or item of equipment? why are performance standards needed? what are the sources of performance standards? think about this and complete the activity on the next slide before progressing. learner activity this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). correct close close close close close close what is a ‘performance standard’ for a safety critical system or item of equipment? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). this is a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg ‘farsi’ model). a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg hsg 65) which define who does what, when and with what result). a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg hsg 65) which define who does what, when and with what result). a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg hsg 65) which define who does what, when and with what result). a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg hsg 65) which define who does what, when and with what result). a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg hsg 65) which define who does what, when and with what result). a general term used to mean an agreed standard that is set, and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety (eg hsg 65) which define who does what, when and with what result). a general term used to mean an agreed set standard (eg iso 45001 occupational health and safety management system), and against which actual performance is measured and judged. a general term used to mean an agreed set standard (eg iso 45001 occupational health and safety management system), and against which actual performance is measured and judged. a general term used to mean an agreed set standard (eg iso 45001 occupational health and safety management system), and against which actual performance is measured and judged. a general term used to mean an agreed set standard (eg iso 45001 occupational health and safety management system), and against which actual performance is measured and judged. a general term used to mean an agreed set standard (eg iso 45001 occupational health and safety management system), and against which actual performance is measured and judged. a general term used to mean an agreed set standard (eg iso 45001 occupational health and safety management system), and against which actual performance is measured and judged. what is a ‘performance standard’ for a safety critical system or item of equipment? which statement is correct? submit submit submit submit submit submit used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. correct close close close close close close why are performance standards needed? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. used as the basis for managing the hazard through the life cycle of the plant/installation; and to ensure that safety critical elements will perform according to the design criteria and expectations, and will remain suitable and continue to function for their intended purpose. necessary to ensure the occupational safety of people. necessary to ensure the occupational safety of people. necessary to ensure the occupational safety of people. necessary to ensure the occupational safety of people. necessary to ensure the occupational safety of people. necessary to ensure the occupational safety of people. to define how the control measures, safety critical elements and other non-safety critical elements should perform. to define how the control measures, safety critical elements and other non-safety critical elements should perform. to define how the control measures, safety critical elements and other non-safety critical elements should perform. to define how the control measures, safety critical elements and other non-safety critical elements should perform. to define how the control measures, safety critical elements and other non-safety critical elements should perform. to define how the control measures, safety critical elements and other non-safety critical elements should perform. why are performance standards needed? which statement is correct? submit submit submit submit submit submit click all that apply and press ‘submit’. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. correct close close close close close close what are the sources of performance standards? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. various performance standard models are used for setting performance standards in process safety eg ‘farsi’ model which can be described in terms of its functionality, availability, reliability, survivability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, reliability, suitability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, reliability, suitability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, reliability, suitability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, reliability, suitability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, reliability, suitability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, reliability, suitability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, responsiveness, survivability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, responsiveness, survivability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, responsiveness, survivability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, responsiveness, survivability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, responsiveness, survivability and interdependency. source of performance standard ‘farsi’ can be described in terms of its functionality, availability, responsiveness, survivability and interdependency. what are the sources of performance standards? which statement is correct? submit submit submit submit submit submit click all that apply and press ‘submit’. safety-critical element (sce) a good definition of this terms is included in uk regulations designed for the offshore oil and gas industry. “such parts of an installation and such of its plant (including computer programmes), or any part thereof: the failure of which could cause or contribute substantially to; or a purpose of which is to prevent, or limit the effect of a major accident.” source: the offshore installations (safety case) regulations 2005 key terms reasons for performance standards for safety critical systems/equipment necessary to ensure the safety of an asset. to ensure that safety critical elements will perform according to the design criteria and expectations. each sce is assessed and interdependencies/interactions examined. management of change (moc) in high-hazard industries, it is recognised that even seemingly small changes (eg to equipment) can have large potential consequences if they are not thought through properly beforehand. moc is a management control approach to make sure that proposed changes are properly addressed and authorised. performance standard (ps) this is the general terms used to mean an agreed standard that is set and against which actual performance is measured and judged. various models and methods are used for setting performance standards in process safety eg, the ‘farsi’ model. key terms process hazard analysis (pha) a systematic analysis of the hazards (and their potential causes and consequences) relevant to a particular process. this may use one or more specific techniques such as hazop, what-if of fmea. farsi a model for performance standards, which can be described in terms of its functionality, availability, reliability, survivability and interdependency (usually abbreviated to ‘farsi’). key terms reasons for performance standards used as the basis for managing the hazard through the life cycle of the plant/installation. provide assurance that critical risk control systems will remain suitable and continue to function for their intended purpose. the farsi model for defining performance standards functionality availability reliability survivability interdependence there are different ways to define performance standard requirements for safety critical elements, the common one is 'farsi': functionality the task the particular element is required to perform. the standard it needs to perform to. how the performance can be measured, eg fire drenching system (reference to required water flow rate, etc). availability proportion of time it needs to be available (and capable) to perform. will it perform under the conditions which are expected? probability of failure on demand (pfd) this is the probability that a component will fail to perform its safety function at the time it is needed. note that a component may have more than one safety function/mode of operation and the pfd may be different for each of these functions. mean time between failure (mtbf) this is the calculated average time that elapses between failures of a system, equipment or a component. this is used in relation to predicted failures of repairable systems. key terms safety integrity level (sil) this is related to the concept of safety integrity which is the average probability of a sis performing its function (under the stated conditions for a required period to time). the sil is then used to specify the safety integrity requirements that the sis needs to have. there are four levels in the sil system, 1 being the lowest and 4 the highest. safety instrument system (sis) an instrumented system used to implement either a safety control and/or protection function. an sis is made up of three connected parts (sensor/s, logic solver/s, final elements). the logic solver decides what action to take depending on the sensor input. the final element carries out the physical action, eg, valve. the three parts of the sis may be based on programmable electronics/software. key terms reliability how likely is it to operate (or fail to operate) on demand often expressed using pfd or mtbf values. active systems can be assigned target values, eg no more than 1% downtime for individual detectors in any 12 month period. sil value used to specify safety integrity needs for safety instrumented systems (siss). reliability is closely related to the previous ‘availability’ survivability operate under specified conditions, particularly post-event. for example, fire and gas system shall survive fire or explosion for as long as the temporary refuge is protected for. interdependencies do other systems require to be functional for it to operate? fire/smoke detection system have a dependency on ‘emergency power’ and an interaction with ‘hvac dampers’. esd requires power to operate. activity what are the interactions/dependencies in each of the following cases: blowdown? deluge? emergency shut-down? think about this and complete the activity on the next slide before progressing. learner activity correct close close close close close close match the statements to the correct heading and press ‘submit’ when finished. incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct submit submit submit submit submit submit match the statements to the correct heading and press ‘submit’ when finished. depends on detection and valve operation depends on water (foam) supply and detection and valves shutdown depends on detection/control systems and valve operation which depends on power supply 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances 3.5 electricity/static electricity. 3.7 reaction hazards. 3.8 bulk storage operations. element 3: process safety hazard control activity what are the main uses of steam in your organisation? think about this and complete the activity on the next slide before progressing. learner activity close close close close close close correct use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as motive power use of steam as motive power use of steam as motive power use of steam as motive power use of steam as motive power use of steam as motive power use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. select five common uses of steam usedin organisations incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as a source of heating use of steam as motive power use of steam as motive power use of steam as motive power use of steam as motive power use of steam as motive power use of steam as motive power use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam to move liquid and gas use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for separation of vapour streams use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. use of steam for cleaning. use it for cooking foods, steam cleaning of carpets and flooring use it for cooking foods, steam cleaning of carpets and flooring use it for cooking foods, steam cleaning of carpets and flooring use it for cooking foods, steam cleaning of carpets and flooring use it for cooking foods, steam cleaning of carpets and flooring use it for cooking foods, steam cleaning of carpets and flooring select five common uses of steam usedin organisations submit submit submit submit submit submit ironing clothes to add enough humidity  ironing clothes to add enough humidity  ironing clothes to add enough humidity  ironing clothes to add enough humidity  ironing clothes to add enough humidity  ironing clothes to add enough humidity  uses of steam within the processing industries as a source of heating (direct or indirect) for spaces and processes: steam for heating at positive pressure used in food processing factories, refineries and chemical plants; saturated steam: heating source for process fluid heat exchangers, reboilers, reactors, combustion air pre-heaters and other types of heat transfer equipment; steam humidification is also used in space heating systems. motive power to drive equipment, eg turbines. move liquid and gas streams in piping. separation of vapour streams, eg ‘steam stripping’ in distillation towers. cleaning. uses of steam within the processing industries wetting - in processes requiring humidification or moistening of materials, eg paper mills and production areas using pellets. atomising - injecting steam into fluids atomises the fluid and increases surface area, eg flare stacks and other burners. sterilisation - in processes for microbiological control, eg food, pharmaceuticals. uses of steam within the processing industries properties of saturated steam produced at the boiling point of water (which depends on pressure). visible, eg vapour coming from a boiling kettle. releases its heat immediately (more efficient than hot water). boiling point of water is 100°c at standard pressure but increases with pressure. so, possible to have steam above 100°c. condensate formation: steam still wet (3-5% of water may be entrained in the steam). reduces heat efficiency. problems for pipe work and reactor vessel. condensate has to be removed as near to the point of use as possible by steam traps. sometimes known as ‘wet steam’. properties of saturated steam made from saturated steam subjected to further pressure and heat. an invisible gas. temperature of > 200°c. rapidly releases heat. does not produce condensate when it meets air or surfaces. suitable for being transferred long distances through pipework or driving equipment such as turbines. properties of saturated steam watch a video on superheated steam. video steam hazards thermal expansion vacuum formation water in steam lines (water hammer) thermal expansion (of pipes, vessels, etc): use flexible/expansion joints. flexibility built into pipelines/vessels by using expansion joints or expanding sections that compensate for the thermal movement. other design features (including bellows) can also be used to allow the material to expand without causing a rupture. vacuum formation: cooling creates condensate (volume reduction). leads to vacuum formation. use of ‘vacuum breakers’ in steam lines to equalise pressure. ensure sufficient pressure to discharge condensation. steam hazards water in steam lines (water hammer): water in a pipeline striking a fixed object under high pressure, eg a bend or tee in pipeline. striking the bend/tee sets up vibrations caused by the pressure shock that is imparted. mild cases – knocking noise (hammer) + pipe movement. severe cases – pipe fracture and loss of contents. steam hazards water hammer (continued) – two basic mechanisms in steam systems: water entrained in steam being rapidly moved through pipe (as condensate); steam rapidly condenses (due to being surrounded by lower temperature condensate). large pressure drop causes cooler condensate to rush in to fill the void created. steam hazards water hammer control: good design of pipework and process controls; removal of condensate; maintaining steam traps and drainage; improving the quality of the steam (minimise water), steam velocity and flow. steam hazards water hammer control: maintain pipework insulation; control/avoid pressure drops; avoiding the risk of explosion by not mixing hot and cold (high pressure steam with ‘cooled’ condensate); ensuring steam pressure and temperature are reached before allowing steam flow. steam hazards water hazards vacuum formation during draining operations hydrostatic testing / weight cooling towers – legionella and water-vapor fog vacuum formation during draining operations: draining without proper venting can create (partial) vacuum; vessel collapse/deformation; ensure ‘vacuum breaker’ valves. water hazards hydrostatic testing: used for final proof testing to identify leaks; vessel supports designed for gas vessel may not be designed to withstand weight of water; vessel pressurised with water; check for leaks; water removed and vessel dried; possible vacuum formation on draining water; possible corrosion (contaminants in water); ensure sop for venting, draining and removal of hazardous conditions. water hazards the ‘weight’ method (alternative to hydrostatic testing): vessel pressurised with water; measure weight of water retained and expelled when the pressure is released - to calculate the degree by which the vessel itself expanded. water hazards cooling towers – legionella and water -fog: legionella bacteria exists in water; grows between 20°c and 55°c (37°c is ideal); feeds on nutrients in water; risk of disease if water droplets containing viable bacteria are inhaled; cooling towers - hot water/high air flow generates aerosols (‘water-fog’). water hazards cooling towers – controls: treat water with a biocide; remove nutrients from water; controlling temperature in make-up water and in ponds; prevent the spread of escaping water droplets by fitting drift eliminators. drift eliminators - these are fitted in the top (or side) of the tower and force the water which has been forced out to fall back into the tower. water hazards inert gases noble gases (he, ne, ar) + other gases (n2, co2). colourless and odourless. generally unreactive (except in rare occasions). used to exclude oxygen. very good fire and explosion suppressants. typical uses of inert gas inerting equipment to prevent flammable atmospheres. preparing equipment for maintenance by purging out hydrocarbons. removing air/oxygen in equipment before start-up. typical uses of inert gas blanketing storage tanks to prevent the ingress of air. certain welding operations. decommissioning equipment to prevent the ‘rusting’ process. use as fire-fighting agent. pipeline freezing operations. instrument air back-up. inerting/purging inert gas is applied to reduce/remove oxygen (in air) – the air is forced out. important to ensure that: all the air is removed; overspill of the inerting gas is controlled; assessment made of the likelihood of any electrostatic effects that might compromise the area as fluids are removed or gases discharged. inerting/purging uses: to prevent any fire or explosive atmosphere from forming by removing air (oxygen) in the system; reaction processes: to displace oxygen and create a non-explosive atmosphere; during maintenance: to remove flammable material and ensure oxygen/flammable mixtures do not arise. inerting/purging hazards and risks creates non-breathable atmosphere (displaces oxygen). nitrogen differentially replaces carbon dioxide which prevents the breathing reflex. low temperatures - potential for serious cold burns: gaseous n2 and co2 are liquid when compressed (co2 - 20°c, n2 - 210°c); need to insulate storage vessels and pipe work to protect from the danger of direct contact with people as well as to maintain temperature. blanketing of storage tanks addition of an inert gas into the head space of a tank removes risk of flammable or explosive atmosphere as the tank is being filled (or emptied, air entering via vents) because an oxygen rich head space is left above the liquid in the tank. nitrogen is the more common gas used. a pad-depad valve is used to adjust the amount of inert gas in the head space. pad depad as the head space gets bigger the valve opens introducing the inerting gas. when the head space gets smaller (as the tank is filled) the other part of the valve opens allowing the inerting gas to return to its storage vessel fire-fighting agent inert gases extinguish fire by replacing the oxygen. risk of exposure to asphyxiating atmospheres. typically: co2 used in office areas and on some plant. 52% n2 , 40% ar, 8% co2 mixture for industrial and process plant. pipeline freezing operations n2 often used as a coolant because of its very low temperature. injecting liquid n2 in a blanket around a pipe freezes the contents allowing: maintenance; alterations; and repair work. cost effective and relatively easy. this video highlights hazards of asphyxiation. video nitrogen use as back up instrument air valve and process operated pneumatically may in some circumstances also be operated by n2. dry and readily available. will not support fire/explosion. ensure safety of workers and pipe work is protected. o2 level detectors may be required in work areas to alert workers in the event of a n2 leak (which will reduce o2 levels). 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances. 3.5 electricity/static electricity. 3.7 reaction hazards 3.8 bulk storage operations element 3: process safety hazard control basic circuitry for current to flow characterised by: potential difference (voltage), current, resistance light bulb battery switch electron flow conventional current flow basic circuitry for current to flow the basics of electrical circuits electricity in a very basic sense involves the flow of electrons, the negatively charged part of atoms, from one place to another through a conductor. when the two poles (or terminals) of a battery are connected to a metal wire (or other electrically conductive material) to make a 'circuit', it causes a current to flow. the current flows due to the movement of electrons through the wire, 'pushed' along by the voltage (also called the 'potential difference') between the two poles. basic circuitry for current to flow you will have noticed that the poles of a battery are labelled as positive (+) and negative (-). by convention, current flows from positive to negative (but in fact the electrons flow in the opposite direction). the potential difference is measured in volts and the current is measured in amps. when connected to a battery to make a circuit, some materials are better conductors of electricity than others (i.e. flow is easier through some materials than others). we describe this using the property 'resistance'. a good conductor has a low resistance, e.g. copper; a poor conductor has a high resistance and is known as an ‘insulator’, e.g. glass, plastics, dry wood, rubber. voltage × current × resistance potential difference (voltage), current and resistance related by the ohm’s law equation: using this relationship it is thus possible to work out a value of one of the elements if we know the other two. by adjusting any of these the electrical supply can be modified to fit certain applications. v = i × r quantity unit name unit symbol voltage volt v electric current ampere (amp) a resistance ohm ω types of current direct current (dc): current flows in one direction with a constant voltage polarity (same difference between each end of the wire); used in short distance applications, eg batteries. alternating current (ac): current that changes direction periodically (in phases moving in both directions along the wire) along with its voltage polarity; for applications requiring greater power (operates effectively over much longer distances). hazards of electricity depends on: amount of current flowing through the body (ohm’s law - depends on v and r). frequency. path electricity takes through the body. duration. hazards of electricity electricity in process plants generally involves the application of low resistant circuits at high voltage for power and high resistant circuits for heating applications. from v=ir equation it can be seen that a high voltage with a low resistance requires a high current. high current is dangerous. safety: the human body is generally a good conductor when earthed; hazards of electricity but comparatively low voltages can cause injury. for example, voltages greater than 50 v applied across dry, unbroken human skin can cause heart fibrillation if they produce electric currents that pass through the chest. the amount of current will reflect both the source of electricity as well as the part of the body which comes into contact with the power source. dry skin offers more resistance to a current than wet skin. if the current is sufficient it will do damage. impact on the body 0.5 – 2ma threshold of perception 2-10ma painful sensation 10 – 25ma inability to let go. danger of asphyxiation 25 – 80ma loss of consciousness from heart or respiratory failure 80 – 2000ma ventricular fibrillation , (erratic heart functioning) burns at point of contact 2000ma and above cardiac arrest, burning of internal organs and tissues leading to death impact on the body frequency of the current may cause muscle spasm and result in the muscles ‘freezing’: will cause the hand to hold on and the person will be unable to let go; heart and lungs may also be affected and stop altogether. longer exposures at even relatively low voltages can be just as dangerous as short exposures at higher voltages. low voltage does not imply low hazard. electric arcs and sparks occurs when two conductors are separated when carrying a charge: break in the circuit can result in the current jumping from one conductor to the other, eg a switch mechanism or a short circuiting of a power supply line. can be extremely violent - extreme heat + bright light. electric arcs and sparks temperatures are generally very high - perhaps 20,000 to 30,000 °c. the electricity continues to follow its path and in doing so causes the intervening non-conducting material - usually air - to change properties, with the result that a massive current is produced. e.g. electric powered trains cross tracks and a brief flash of high intensity light is emitted when the close connection between train and live rail is temporarily broken. sparks caused are, in a many respects, similar to an arc but involve much less power and limited ionisation of the surrounding air; an arc is a very large spark, but definitions are unclear and vary. electric arcs and sparks risk to workers in the vicinity. risk of ignition of any volatiles, dusts, clothing. risk of explosion (ignition of flammable atmosphere). possible serious damage to equipment and the power distribution system. watch this arc flash demonstration video. video watch this arc flash accident video. https://www.youtube.com/watch?v=dpjtkngmsys&list=pl video how arcs/sparks occur during normal operations high-voltage switch rooms and panels. defective or poorly wired cabling and connections. operation of relays. incorrect use of tools. adopting incorrect procedures resulting in shorting or bypassing of safety controls (live working especially). low-voltage systems may be at greater risk as the automatic circuit breaker may not be designed to act as fast as that on high and very high voltage installations. how arcs/sparks occur during normal operations failures in switches. accumulation of dust and debris, especially in medium- and high-voltage systems in contact areas may result in arcing. condensation and corrosion. poor or faulty design and installation. dust/debris, especially in medium and high voltage systems in contact areas may result in arcing. condensation/corrosion may affect electrical systems and give rise to a possibility of shorting and sparks or arcing. this video gives workers’ accounts of an incident that occurred in 2012. video electrostatic charges charge builds up on the surface of a non-conducting material which is then dissipated by discharging it to a conducting material. may be created by pressing two materials together (if materials are of the right type): electrons pulled from the surface of one of them onto the other; a static charge is then created (one surface becomes + and one – ). more efficient to rub two surfaces together ‘tribocharging’. electrostatic charges non-conductors give up or attract electrons relatively easily so that when exposed to heat, pressure or friction electrons will be released or absorbed. material then becomes either negatively or positively charged depending on whether it has absorbed or given up electrons. in this condition the material now represents a potential difference to the surroundings which then creates a potential for sparking to occur as the charge is dissipated. in an explosive or flammable atmosphere the discharging spark may have sufficient energy to ignite it. electrostatic – other methods of creation pyroelectric effect: applying heat to a material at one point causes the electrons to move and one surface becomes positively charged and the other negatively. piezoelectric effect: stress applied to certain crystals creates a charge. inducing a charge: placing charged material near to a conductor (or non-conductor) which allows its electrons to move freely. the charged material induces a charge in the originally uncharged material. activity how can static charge occur in process settings? think of some examples of how it can happen. think about this and complete the activity on the next slide before progressing. learner activity close close close close close close correct liquid-liquid gas-liquid solid-liquid gas-solid solid-solid pneumatic transport of powders/solids when liquids are poured, pumped, filtered, agitated, stirred or flow through pipes.  when fluids are spayed in air a static charge can built up fairly rapidly in some fluids. movement of conveyor belts (and gears) resulting in friction. a charge develops and will discharge from one surface to another. when liquids (e.g., petroleum solvents, fuels) move in contact with other materials. how can static charge occur in process settings? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct submit submit submit submit submit submit how can static charge occur in process settings? when liquids are poured, pumped, filtered, agitated, stirred or flow through pipes.  pneumatic transport of powders/solids when liquids (e.g., petroleum solvents, fuels) move in contact with other materials. movement of conveyor belts (and gears) resulting in friction. a charge develops and will discharge from one surface to another. when fluids are spayed in air a static charge can built up fairly rapidly in some fluids. liquid-liquid solid-solid gas-liquid solid-liquid gas-solid close close close close close close correct flowing fluids in pipe lines volatiles discharge from tanks/vessels dust on conveyors electromagnetic generator use of battery static in process settings: which statement are true and which are false? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct flowing fluids in pipe lines volatiles discharge from tanks/vessels dust on conveyors electromagnetic generator use of battery static in process settings: which statement are true and which are false? submit submit submit submit submit submit types of static - spark discharges spark discharges: these result where a non–conductive (insulated) material (e.g. plastic) comes into proximity with a charged material, which discharges across an air gap, heating the air to high enough temperatures to cause it to glow. e.g. metal flange on a glass pipe (where the metal is insulated by the glass and is therefore non-conductive) or a person insulated from earth by shoes or carpet and touches their finger to charged object, such as a door knob). occurs between conductors which are not electrically connected. types of static - corona discharge corona discharge: often found in high voltage systems where a point electrode is created and sparking occurs as a result of the ions in the surrounding air being energised, e.g. in generators, transformers and capacitors. types of static - brush discharge brush discharge: like a corona discharge but results from a blunt electrode and the discharge is therefore wider. brush discharges may occur between an insulating material and a conductor or between two insulating materials. types of static - propagating brush discharge propagating brush discharge: results from thin insulating films in close contact with a conductor. the discharge happens at several points of the surface. types of static - conical pile discharge (maurer discharge) conical pile discharge (maurer): this happens when solid material (e.g. dusts) is poured into a container forming conical shape in a the presence of charged air. the sliding of the material in the air causes charge to develop which is then discharged via the top of the “cone”, e.g. : filling of highly insulating bulk solids into silos and containers. types of static - streaming current charge develops in flowing liquids in pipes (friction). contact enables electron exchange to take place. liquid picks up a charge which is then moved through the pipe as the liquid flows, accumulating charge on the way. insulating liquids unable to dissipate charge back through the liquid and will discharge when coming into contact with air or another conductor. typical situations that generate electrostatic charge movement on conveyer belts. transporting materials. pouring solids and liquids into containers. sieving and grinding operations. agitation and stirring. creation of charge on workers walking in insulated shoes or on an insulated surface. control of electrostatic charges through bonding and grounding fixed objects - provide a permanent connection from the plant, structure, etc to earth. moveable objects (such a filling bins) - ‘flying’ lead attached to the bin which is then clipped onto an earthing connection at the point of use. both require a good connection – eg not covered in dust and debris. where direct earthing not possible, eg liquids in glass-lined pipe or containers, use a tantalum plug in the line or by dipping an earth lead extended to the bottom of the container. activity what consequences might a sudden power outage have on an installation such as a refinery or large chemical plant? think about this and complete the activity on the next slide before progressing. learner activity close close close close close close correct can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. what consequences might a sudden power outage have on an installation such as a refinery or large chemical plant? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. can not maintain the safety control functions. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. a break in process activities, reactions, pumping of materials, etc due to a power outage, may well create a hazardous situation. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. exposing failsafe systems, such as emergency shut-down (esd), to failure. disrupt communications, water, and services. disrupt communications, water, and services. disrupt communications, water, and services. disrupt communications, water, and services. disrupt communications, water, and services. disrupt communications, water, and services. what consequences might a sudden power outage have on an installation such as a refinery or large chemical plant? submit submit submit submit submit submit click all that apply and press ‘submit’. power outages two approaches to consider uninterruptible power supply (ups) – for short time outages, up to an hour. generator – for longer outages (often in tandem with the ups). ups takes power (ac), stores it in a battery (dc) via a rectifier and then passes it back through an inverter (which restores the dc to ac) and then back into the distribution system. three approaches: offline; online; line interactive. off line: offline system takes power from the mains and then stores it in a battery. it remains disconnected from the internal distribution system until there is a demand. switching on can take 25 milliseconds, which may be significant for critical control functions. ups online: online approach is used where electrical isolation is necessary or for equipment that is sensitive to fluctuations in power supply. it is generally used for high-power applications. when the external power source fails, the inverter (which is permanently connected) drops out and power is continuously supplied. when external power is restored the rectifier resumes charging the batteries. line interactive: the line interactive approach is an online approach which selectively taps off from the transformer under varying power conditions. this may result in small loses of power as the switchover is made. there is typically a 2 to 4 milliseconds delay during the transfer from ac power to battery backup power. the choice of approach depends on cost, requirements and functionality. 3d ups (kfs university) part 1 video 3d ups (kfs university) part 2 video generators portable generators: can be used before the ups ceases to function; matched to the power requirement of the equipment to which they are to be connected; kept on site or hired in; safety procedures to ensure the safe connection and disconnection in energised systems. loss to main power can be very serious, both for safety and production. the loss of power fro even a few seconds can cause microprocessors to fail. ups is battery powered with limited life. need to have back up generators generators fixed generators: can be installed to match the expected total load or partial required load of the plant; dead time between start of the outage and start up of the generators; power surges. generators two critical aspects with generators maintenance and testing to ensure they are fit for purpose when required in an emergency. ensure adequate fuel supplies are available. 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances 3.5 electricity/static electricity. 3.7 reaction hazards. 3.8 bulk storage operations. element 3: process safety hazard control activity there are three basic physical states in which substances can exist: gas; liquid; solid. consider the characteristics of each of these. think about this and complete the activity on the next slide before progressing. learner activity complete close close close close close close click the icon below to download your reflection as a document file and save this for your own records. download download download download download download sample answer continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> solids both a fixed shape and size and retain their shape and volume. they do not flow. solids may form large objects or exist as discrete small objects such as dusts and powders. each particle of a powder retains its shape, even though reference is made to “free flowing” when it is poured- e.g. sugar. physical forms of dangerous substances type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> describe the physical state in which solids can exist: sample answer continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> liquids substances which at stp have a fixed volume but take the shape of the container they are in. create a vapour at certain temperatures and when this occurs at stp they are often termed as volatiles. this indicates that above the liquid (open container or head space) the liquid is in its gaseous form. physical forms of dangerous substances type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> describe the physical state in which liquids can exist: sample answer continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> gases state of matter which at atmospheric pressure (at standard temperature and pressure (stp) ) exists in a form which has no defined shape or volume and will uniformly fill the shape of any container it is placed in gas particles may be single atoms, single molecules or a mixture, e.g. ar, n2, co2. characteristics: reactive or non-reactive. heavier or lighter than air. gases when pressurised form liquids. are vapours gases? (often called gases, but not strictly so, is the vapour which exists above a liquid. a vapour is not a state of matter but rather the result of the liquid and gaseous states coexisting at equilibrium at stp. in process safety terms, although there is a difference, it is often usual to refer to gas and vapours as being the same. they exhibit the same properties. vapour usually results from boiling or evaporation). physical forms of dangerous substances type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> describe the physical state in which gas can exist: physical forms of dangerous substances substances can change state. co-exist in more than one state. have different forms (eg dust vs lump). for example, water can be a: gas (superheated steam); liquid (at stp); solid (ice). how form affects risk potential gases fire and/or explosions: flammable gases/vapours form explosive mixtures with air even at low concentrations. harm to human health and/or damage to materials; asphyxiants (eg n2, co2); corrosive (eg nh3, cl2 ). how form affects risk potential liquids much easier to contain a release (eg by bunding) than it is for gases. fire and/or explosion: fire spread through liquid flow (fuels and solvents). harm to humans, plant and the environment: acids, alkalis, etc. how form affects risk potential solids risk depends on shape, form and size: large size harder to ignite/explode/react; smaller size (eg dusts, powders) much easier to ignite/react. finely divided metals are highly dangerous, eg exposure of aluminium powder to water. dusts mixed with air present a very large surface area creating a flammable atmosphere, eg sieving operations. how form affects risk potential the reason carbonaceous dusts are so vulnerable to fire and explosion is because if they become mixed with air they present a very large surface area creating a flammable atmosphere. in many operations involving powders, it is essential to mix them with some other reactant. in doing so the powder becomes dispersed in air and may therefore become flammable or explosive. this risk can often be overcome by inerting the atmosphere in the mixing vessel. likewise, operations such as sieving and similar activities create a dust cloud (and note - also possibly an electrostatic charge) making them a potential risk for fire/explosion. explosive substances risk of exploding in the right mixture with oxygen (air) if sufficient energy is available. explosive substances have very low minimum ignition energies. the energy may be created by heat, shock or electric charge (such as electrostatic friction). oxidising substances add oxygen to other substances. they easily ‘oxidise’ susceptible substances (eg metals, metal hydrides and organics) and create conditions for a fire to occur or make a fire worse. examples of common oxidising agents: nitric acid, hypochlorites (halogen) and hydrogen peroxide. key term flash point the lowest temperature at which sufficient vapour is given off to ‘flash’, ie ignite momentarily (not continue to burn), when a source of ignition is applied to that vapour. key term vapour density vapour density expresses the mass per unit volume of vapour, i.e. its weight. it is measured relative to hydrogen (air in usa). key term vapour pressure the pressure exerted by a vapour in equilibrium with its liquid (or solid) state. case study: fire at allied colloids ltd, bradford, uk, 1992 one of the main causes of this incident was storage of incompatible chemicals together in the same area of a warehouse. azodiisobutyronitrile (azdn), a thermally unstable reducing agent was stored with a range of oxidising agents, including sodium persulphate (sps), with which it can react violently. azdn had been misclassified as an oxidising agent by allied colloids.the azdn had also been stored close to a heater, which caused it to decompose. some became mixed with the sps, causing an explosion (some of which are thought to be dust explosions) and an intense fire, the extinguishing of which caused a great deal of environmental damage (from the fire water runoff into local rivers). read more about this here. watch this video about the allied colloids case study video flammable liquids flammable liquid category condition 1 flashpoint < 23°c and initial boiling point ≤35°c 2 flashpoint < 23°c and initial boiling point >35°c 3 flashpoint ≥23°c and initial boiling point ≤60°c (i.e. flashpoint between 23°c and 60°c inclusive) flammable gases 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances. 3.5 electricity/static electricity. 3.7 reaction hazards 3.8 bulk storage operations element 3: process safety hazard control activity what is a chemical reaction? what affects how quickly a reaction takes place (or whether it happens at all)? think about this and complete the activity on the next slide before progressing. learner activity complete close close close close close close click the icon below to download your reflection as a document file and save this for your own records. download download download download download download sample answer continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> below factors affects how quickly a reaction takes place: concentration physical form (how intimately the reactants mix), temperature pressure presence of “impurities” (especially what we call ‘catalysts’) central to understanding reactions is to understand energy. energy is mostly controlled by temperature and pressure. reactions can be further facilitated by the use of catalysts. what affects how quickly a reaction takes place(or whether it happens at all)? type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> sample answer continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> a chemical reaction is: conversion of one ‘substance’ into something else by combining with other chemicals. such as combustion/burning, ‘rusting’ of iron, neutralisation (acid + alkali). physical changes that may occur (sometimes gases are produced from solids/liquids during the reaction), including the production of heat (exothermic). process industries rely upon chemical reactions to produce new materials. various activities involved : mixing, stirring, heating, cooling. basic process (batch, semi-batch, or continuous operations) involves taking raw material from storage, undertaking the reaction(s), isolating the product and preparing it for use. what is a chemical reaction? type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> this is a generalised trend, and assumes all other things being equal (e.g. constant reactant concentrations, constant pressure, etc.). in reality, reactants will be consumed, the rate will then slow and halt at some point. chemical reactions involve energy to bring about the required changes. in the majority of cases this energy is provided by raising the temperature. in simple terms a chemical reaction results from the colliding together of the particles of two or more different chemicals. effect of temperature as the temperature increases more energy is imparted to the particles and eventually (at what is known as the activation energy) there are sufficient highly energised particles to cause the reaction to take place. in very general terms, each raise of 10° causes a doubling in the rate of reaction. but for the most part this applies to manufacturing processes. thus by adjusting temperature it is possible to control the speed or rate of reaction. effect of temperature this does not apply to all reactions, e.g. mixing an acid and an alkali is an instantaneous reaction which does not require energy in the form of heat to make it happen. effect of temperature for gases, increasing pressure is the way you increase concentration (the gas equation p = nrt/v, where n/v is number of moles of a gas per unit volume (i.e. the concentration)). pressure pressure pressure increase has a similar effect to temperature. application of pressure reduces the space (volume) between the particles and thereby increases the likelihood that collisions will occur. speed of reaction controlled by pressure. in many cases a combination of temperature and pressure adjustment is used. this shows an energy diagram for a typical exothermic reaction – where heat is given out (the products have lower energy than the reactants). catalysts a catalyst is a medium put into a reaction vessel which changes the pathway (mechanism) of a reaction so that particles are forced into closer proximity. increases the speed of a reaction by lowering the activation energy. catalysts are not destroyed or changed during a reaction: - generally reusable. - may suffer from poisoning by contamination with undesired trace substances in the reaction mixture. catalysts exothermic and endothermic reactions exothermic (very common) produces heat, eg combustion reaction. endothermic (less common) takes in heat from the surroundings, eg reaction between ‘vinegar’ and ‘washing soda’. thermal runaway reaction an out of control exothermic reaction. if the heat produced by the reaction is not removed fast enough the reaction speeds up. the reaction may then “runaway”. mainly applies to batch processes. thermal runaway reaction - causes incorrect vessel charging: incorrect reactants; incorrect volumes of reactants; wrong specification of raw materials (impurities). incorrect use of catalysts. poor/failed temperature control. poor/failed mixing. loss of power (which affects critical controls). maintenance failures. instrumentation failures. variations in operation: result of the failure to apply moc procedures; or a basic lack of understanding of the reaction chemistry. design failure resulting in insufficient controls, eg heat cooling. insufficient operator training or familiarisation. inadvertent addition of compressed air, nitrogen, steam, etc. (increases pressure). exposure of the vessel to fire. thermal runaway reaction - causes venting or dumping of product and materials. loss of production and probably damage to equipment. unintended chemical reactions, such as decomposition or other runaway reactions. vessel over-pressure: catastrophic rupture – missiles, etc; loss of containment – toxics, flammables (fire/explosion). thermal runaway reaction - causes thermal runaway reaction – consequences. watch seveso incident below. video thermal runaway reaction - protective measures containment within the reactor. crash cooling. drowning and quenching of reactor. emergency venting/dumping of reactants. containment correct design and construction of the vessel to withstand the pressure and temperature. problem for vapour producing reactions - pressure rise can be too great to be effectively resisted. cost of building vessels with sufficiently thick walls may be prohibitive. encase in concrete or a steel/concrete bunker. containment is advantageous as there is no venting and the control is passive requiring no intervention. thermal runaway reaction - protective measures crash cooling emergency or crash cooling involves the activation of additional cooling to the reactor. use some other cooling process, e.g. reflux condenser or an external heat exchanger. pump a refrigerant though the reactor coils or into the jacket. issue - temperature too low, material will solidify making the situation worse. sometimes the term crash cooling is also used to describe the addition of water (other cooling agent) to the reactor, which is more properly a form of quenching. thermal runaway reaction - protective measures drowning and quenching supplying a significant volume of cold non-reactive agent into the reactor - usually water direct into reactor vessel from gravity feed tank discharging into reactor via temperature activated valve. or dump into a tank of coolant, achieving the same effect. add non-reactive diluent. active quenching: use an agent which can alter the reaction taking place by inhibiting the reaction. (it needs to be carefully chosen so that all possible circumstances are accounted for, but provides a substitute for a direct acting inhibitor.) thermal runaway reaction - protective measures emergency venting reactor vessels are fitted with a vent to release excess pressure. vents may not be sized to take the full over pressure caused by the reaction. the use of the emergency pressure relief may need to be supplemented and in any event the discharge should go via an emergency effluent handling or discharge system such as vapour-liquid separator, (knock out drum). thermal runaway reaction - protective measures emergency venting (continued) bursting disk - pressure release is set at a predetermined level so that venting takes place before the runaway has become critical. dumping involves emptying the reactor and sending the contents for treatment, e.g. scrubber to separate out and recover materials or flared off through a flare stack. it is not always possible to design a protective system to cope with the full consequences of a runaway reaction. the events of seveso show this to be true. hence the importance of inherent safety being at the top of the hierarchy of process safety risk control (see element 2).  thermal runaway reaction - protective measures 3.1 operating procedures. 3.2 safe start-up and shut-down. 3.3 safety critical performance standards. 3.4 utilities. 3.6 dangerous substances. 3.5 electricity/static electricity. 3.7 reaction hazards. 3.8 bulk storage operations. element 3: process safety hazard control tanks eight types of tanks used to store liquids fixed-roof tanks (atmospheric tanks). external floating roof tanks. internal floating roof tanks. domed external floating roof tanks. horizontal tanks. pressure tanks. variable vapour space tanks. liquefied natural gas (lng) tanks. hazards and risks overfilling. effects of vacuum. overloading of foundations. failure modes for tank shells and associated pipe work. overfilling overfilling leads to: fluid overflows and escapes (to potential ignition sources – fire and explosion risk); liquid released through the vents intended for vapour; over pressurisation of tank which then ruptures. typically due to: operators unaware of the level in the tank; instrumentation failure in automatic filling systems. effects of vacuum created during tank emptying or draining. tank will deform and/or collapse. use of vacuum breaker valves - loss of pressure in the head space above the liquid is compensated when the tank is emptied. majority of storage tanks used in the process industries are constructed of plate steel. designed to withstand the internal pressure exerted from the contents when filled. weak when exposed to external pressure. this video shows what happens when a storage tank is not properly vented. video here is second example of what happens when a storage tank is not properly vented. video overloading of foundations typically a combination of loading exerted when (relatively light) tank is filled with liquid: density of liquids varies/weight may be significantly different from product to product; tank base may deform when filled/emptied. ground instability (soft/liable to movement): loss of contents. overloading of foundations ensure solid concrete foundation/circular ring beam foundation. design: tank design, construction and foundation suitable for intended contents. use of anchor bolts (eg where expect high winds). failure modes for tank shells and associated pipe work metals used for tanks and pipelines may fail, for example: creep; stress; thermal shock; brittle fracture. creep failure gradual extension of material under a steady tensile stress, more likely to occur at higher temperatures tank or pipe may deform and eventually fracture. failure modes for tank shells and associated pipe work tensile refers to the pulling apart of the metal in a single plane. another aspect is elasticity which refers to the degree to which the material will return to its former length after stretching. tensile strength and elasticity decrease with increasing temperature which means that creep is more likely to occur at higher temperatures. failure modes for tank shells and associated pipe work stress: stress (loading on a material) causes strain (deformation of material). materials fall into two categories: ductile - moves under strain; brittle - breaks under strain. failure modes for tank shells and associated pipe work stress - tensile or compressive loading placed on a material – it’s the amount of force applied per unit area. two broad categories of material: ductile- which will deform significantly under stress before they break brittle - which deform very little before they break. strain is the deformation (relative change in shape/sizes failure modes for tank shells and associated pipe work tank being emptied and then refilled will be subject to movement as the structure responds to the variation in the load placed upon it. in pipework at flanges, openings and connections there will be greater loading and therefore more stress. failure modes for tank shells and associated pipe work stress/loading exerted by: the contents; temperature changes; variations in loading. stress failure also due to: stress corrosion - failure which occurs when a metal corrodes; hydrogen embrittlement - incursion of hydrogen atoms. failure modes for tank shells and associated pipe work thermal shock rapid and extreme temperature changes. different parts of the material expand and heat by different amounts. causes cracking to develop - failure. failure modes for tank shells and associated pipe work brittle fracture occurs suddenly under excessive stress. no or limited elasticity. known as ‘snatch’ loading. low temperatures can increase risk of fracture, eg materials used for storing and conveying lpg. failure modes for tank shells and associated pipe work fatigue failure the formation of cracks as a result of repeated application of loads which individually do not cause failure. may appear as thermal fatigue, contact fatigue, surface or pitting fatigue, subsurface cracking or subcase fatigue, and corrosion fatigue. failure modes for tank shells and associated pipe work fatigue failure fatigue fracture is caused by the combination of: cyclic stress; tensile stress; plastic strain. storage tanks fatigue may also be induced by: wind load/vibration; pump-induced vibration; pedestrians walking on/over components. failure modes for tank shells and associated pipe work activity what sorts of things would you need to consider in siting of bulk storage tanks for dangerous substances? think about this and complete the activity on the next slide before progressing. learner activity close close close close close close the statement highlighted in red is false security fencing of the plant. security fencing of the plant. topography (level ground, sloping ground, high level, low level). topography (level ground, sloping ground, high level, low level). contents (flammable, toxic, polluting). contents (flammable, toxic, polluting). size and type of tank. size and type of tank. correct bulk storage tanks for dangerous substances bulk storage tanks for dangerous substances incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect that's right! you selected the false statement. continue continue continue continue continue continue correct bulk storage tanks for dangerous substances bulk storage tanks for dangerous substances which statement is false? submit submit submit submit submit submit security fencing of the plant. security fencing of the plant. security fencing of the plant. security fencing of the plant. topography (level ground, sloping ground, high level, low level). topography (level ground, sloping ground, high level, low level). topography (level ground, sloping ground, high level, low level). topography (level ground, sloping ground, high level, low level). contents (flammable, toxic, polluting). contents (flammable, toxic, polluting). contents (flammable, toxic, polluting). contents (flammable, toxic, polluting). size and type of tank. size and type of tank. size and type of tank. size and type of tank. the statement highlighted in red is false manufacturer of the storage tank. manufacturer of the storage tank. total inventory (how much material is being stored). total inventory (how much material is being stored). land use planning requirements (legal requirements for siting structures). land use planning requirements (legal requirements for siting structures). purpose of tank in relation to process (feed stock or product, proximity to point of use). purpose of tank in relation to process (feed stock or product, proximity to point of use). close close close close close close correct bulk storage tanks for dangerous substances bulk storage tanks for dangerous substances incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect that's right! you selected the false statement. continue continue continue continue continue continue correct bulk storage tanks for dangerous substances bulk storage tanks for dangerous substances which statement is false? submit submit submit submit submit submit manufacturer of the storage tank. manufacturer of the storage tank. manufacturer of the storage tank. manufacturer of the storage tank. total inventory (how much material is being stored). total inventory (how much material is being stored). total inventory (how much material is being stored). total inventory (how much material is being stored). land use planning requirements (legal requirements for siting structures). land use planning requirements (legal requirements for siting structures). land use planning requirements (legal requirements for siting structures). land use planning requirements (legal requirements for siting structures). purpose of tank in relation to process (feed stock or product, proximity to point of use). purpose of tank in relation to process (feed stock or product, proximity to point of use). purpose of tank in relation to process (feed stock or product, proximity to point of use). purpose of tank in relation to process (feed stock or product, proximity to point of use). the statement highlighted in red is false grounding of the bulk storage tanks. grounding of the bulk storage tanks. distance from sensitive areas (populations, environments, etc). distance from sensitive areas (populations, environments, etc). whether the tank is underground, above ground or mounded, etc. whether the tank is underground, above ground or mounded, etc. close close close close close close correct bulk storage tanks for dangerous substances bulk storage tanks for dangerous substances incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect that's right! you selected the false statement. continue continue continue continue continue continue correct bulk storage tanks for dangerous substances bulk storage tanks for dangerous substances which statement is false? submit submit submit submit submit submit grounding of the bulk storage tanks. grounding of the bulk storage tanks. grounding of the bulk storage tanks. grounding of the bulk storage tanks. distance from sensitive areas (populations, environments, etc). distance from sensitive areas (populations, environments, etc). distance from sensitive areas (populations, environments, etc). distance from sensitive areas (populations, environments, etc). whether the tank is underground, above ground or mounded, etc. whether the tank is underground, above ground or mounded, etc. whether the tank is underground, above ground or mounded, etc. whether the tank is underground, above ground or mounded, etc. siting of tanks - distance(from people, property and other tanks) concentrating on distance from people, property and other tanks containing dangerous substances. separation distances: - useful to limit spread of fire. - away from site boundary, occupied buildings, sources of ignition and process areas. hsg176: for large tanks - minimum distance from boundaries 15m and between 10m and 15m tanks. does not protect from radiation effects siting of tanks - distance(from people, property and other tanks) explosion walls and passive fire protection built into structures. calculation may be necessary to ensure that buildings are robust to withstand worst case scenarios. offsite buildings should be protected by sufficiently large separation distances, but as the buncefield incident showed, this may not be realistic in practice. other considerations: - location of other storage vessels. - dangerous substances. - vulnerability of process lines. - the larger the tank, the greater the separation distances required. siting of tanks - distance(from people, property and other tanks) siting of tanks - ventilation to allow variation in internal and external pressure during filling and emptying. venting to atmosphere - dispersion of volatiles. avoid: flammable/explosive mixtures. release of toxic vapours. most tanks will need to be ventilated for various reasons. tanks above ground should be sited in a well-ventilated unobstructed position separated from the site boundary, occupied buildings, sources of ignition and process areas. this will ensure that any fugitive emissions, spillages, etc. from tanks, transfer facilities, vent pipes, etc. will be readily dispersed in the open air. consider normal venting - including return of material to process, etc. to avoid loss (inbreathing) and emergency venting, e.g. pressure relief exposure to fire. storing liquids in bulk general considerations for storage of these liquids in bulk: size and type of tank. contents (flammable, toxic, polluting). topography (level ground, sloping ground, high level, low level). purpose of tank in relation to process (feed stock or product, proximity to point of use). land use planning requirements (legal requirements for siting structures). total inventory (how much material is being stored). whether the tank is underground, above ground or mounded, etc. distance from sensitive areas (populations, environments, etc.) read more about storing flammable liquids filling of tanks system for filling a tank should be foolproof (required sil- safety integrity level). speed - tank should be able to equalise pressures by means of the designed venting arrangements. procedures and equipment. competent operators. filling of tanks overfilling continuous monitoring to prevent overfilling. volume of vessel and content should be known before filling. alarms two alarm trip systems: high level alarm (lah) - normal operational level exceeded (not a reference point for filling operation); high high level (lahh) - maximum design capacity of the tank. if lahh is exceeded the tank will overpressurise and overflow. read the buncefield explosion and fire report from this link. think what causes of the overfilling of tank? filling of tanks suggested answers: this incident involved explosions and fire at a major bulk fuel storage facility, starting when a fuel tank overflowed. the tank that overflowed had both a level gauge and an independent high-level shutdown, neither of which worked. filling of tanks road tankers the mobile nature means there has to be a temporary (flexible hose) connection made between the road tanker and the storage vessel. liquids are pumped between the two (either using the site pump or a local one on the vehicle). this brings additional risks. road tankers risks drivers drive off leaving the hose still coupled to the tanker: overcome by using breakaway couplings. static - earth bonding: dipping rods should be earthed. siphoning - end of the tank filling line below the lowest normal operating level of the liquid. splash filling - generation of static electricity. floating roof tanks roof floats on the top of the liquid inside the tank. two types: internal and external. advantage: no head space above the liquid: formation of vapour is virtually eliminated. emissions to air controlled. used for the more flammable liquids which have a high vapour pressure, low flash point. external floating roof tank (efrt) key: a: flexible connectors and valves from foam supply devices b: limit chain c: float check valve d: horizontal supply piping to continuous linear spreader nozzles describe the elements of it using the diagram. open to the elements. open-topped cylindrical steel shell roof rising and falling with the liquid level. roof comprises a deck fittings. rim seal system - designed to keep out rain water and prevent vapour emissions. typically on a pontoon although there are other variants. legs enable the roof to stand about 2m clear of the base (enables internal maintenance and inspection work). “landing” the roof. external floating roof tank (efrt) landing the roof typically every 5-10 years (for maintenance). roof of a frt will be landed – rests on its legs (so 1.5-2m high). hazard as tank is emptied/filled, space fills with vapour/air mixture (venting is via in-breather/out-breather vents). sinking the roof heavy rainfall can result in water loading on the roof. sinking may result in loss of buoyancy in the roof due to an imbalance in the supporting structure. incorrect design - if weight of the roof is not supported by the liquid on which it is floating due to insufficient buoyancy. rim seal fires/failures susceptible part of frt is the seal between the roof and the sides of the tank - rim seal. double seal - designed to keep water out and vapour in. fails due to: wear and tear; tank movements; wind pressure, ground movement and internal pressure changes (filling /emptying). rim seal fires/failures rim fails rain water will enter and mix with the contents of tank. surface exposed to air possibility of flammable or explosive mixtures. risk of fire. fire protection system installed in the roof, eg foam discharge. ignition comes from either: lightning strike; localised induced static charge. fixed roof tanks and pressure and vacuum hazards explanation of the image - used for low vapour pressure high flash point liquids which are stable at atmospheric pressure. minimum vapour release as the vapour and air are balanced. fixed roof tanks and pressure and vacuum hazards explanation of the image (continued) variations in temperature caused by weather or by product charging at an elevated temperature will be vented though a pressure-vacuum valve. cylindrical steel shell with a cone- or dome-shaped roof. roof permanently fixed (welded) to the tank shell. modern fixed roof designed to be both liquid and vapour tight. older tanks may be of a riveted or bolted construction and are not vapour tight. pressure and vacuum hazards were introduced earlier. fixed roof tanks especially are susceptible to external pressure. whilst they may be overloaded by overpressurised filling they are more likely to collapse if a vacuum forms internally when they are emptied. bunding – design/construction at least 110% of the total volume of the tank(s). effective to contain any boil over or top loss, and bottom loss and catastrophic failure. allow for access (for inspection, maintenance). allow for rainwater (e.g. drain-off point). maintained (age, deterioration, vegetation, etc.). sealing where pipe work and valves break through wall. effective to contain any boil over or top loss, which may well discharge like a fountain or spigot, as well as bottom loss and likewise catastrophic failure where the contents will disperse like a tidal wave. bunds can be insulated to further protect from effects of temperature, especially fire. mention earth bunding and mounds. shut off valves both inside and outside the bund, inner shut off close to the tank. non-return valves on filling lines. isolating valves and rosovs should be fully functional and fail to safe. lines for draining tanks and the valves blanked off. bunding – design/construction protection from extremes of weather hot and cold climates: temperature variation will affect tanks. hence use of: insulation; trace heating. high wind loadings: distortion can be limited by girding the tank with metal bands. lightning strikes can ignite volatiles and cause catastrophic failure. can create a current which will induce sparking some distance from the strike point. puncture of the tank skin or formation of local hot spots will ignite flammable vapours. floating roof tanks susceptible to lightning strike. lightning strikes control measures: lightening conductors at the appropriate attachment points: tank rim; roof when it is in a high position (efrt). inerting to keep the level of flammable vapours down. ventilation to reduce the hydrocarbons in the air. activity storage of hazardous substances in warehouses presents a number of risks, e.g. allied colloids fire. what factors need to be considered when assessing the potential chemical hazards present and their storage requirements? think about this and complete the activity on the next slide before progressing. learner activity complete close close close close close close click the icon below to download your reflection as a document file and save this for your own records. download download download download download download sample answer continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> example factors when considering storage requirements: separation and segregation of dangerous goods. control of ignition sources. reduce the inventories of chemicals. adequate ventilation. what are their storage requirements? type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> sample answer continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> consider these factors when assessing chemical hazards: the hazardous nature of the stored substances, including its forms, physical property and reaction chemistry information. the potential consequences. how the material will be transported. inventories of chemicals, volume/weight store at any one time. likely sources of ignition, including electrostatic or creation of flammable/explosive atmospheres. topography and how any spillage or release might impact on local areas. this include the presence of drainage, water courses, etc. and the vulnerability of buildings. temperature effects, e.g. some substances may degrade at higher temperature or become unstable. what factors need to be considered when assessing the potential chemical hazards present? type your text here… continue >>> continue >>> continue >>> continue >>> continue >>> continue >>> warehousing assessment understanding the hazardous nature of the substance(s) to be stored: form (liquid, solid, powder, dust, etc); physical properties (flammability, ph, etc); relevant reaction chemistry information (eg reacts with water); safety data sheets (sds) (formerly msds); for substances created and stored on site similar set of information required. warehousing assessment transportation: in what and by what. inventories. sources of ignition - including electrostatic - or creation of flammable /explosive atmospheres. topography. presence of drainage, water courses, etc. vulnerability of buildings. temperature effects. warehousing siting, location and security local topography. proximity of community buildings, housing, schools, hospitals, etc. legal requirements for separation distances of specified materials, e.g. lpg cylinders. routes for receiving and dispensing. vehicle movements. access for emergency vehicles. fire-fighting facilities, eg open water. trespassers. arson. stock control. authorised people only. windows and other openings. security should not compromise fire safety. physical controls, eg lockable doors. inadvertent incorrect storage of incompatible materials. warehousing siting, location and security warehousing inventory consequences of an untoward event: release; spillage; fire, etc. inventory management: reduce the total volume of material that is exposed at any one time. separating storage so that the possibility of mass release is avoided. just-in-time resupply. direct delivery to point of use. warehousing inventoryseparation and segregation of dangerous goods incompatible materials stored separately. store hazardous chemicals separately from each other segregated from all other materials (e.g acids and alkalines) requires detailed understanding of chemical and physical properties agan refer to allied colloids warehousing - control of ignition sources where flammables, identify and control: smoking; use of mobile phones; fork lift trucks/vehicles; hot work; maintenance activities. activity for more information on chemical warehousing, go to this link. learner activity activity: refer back to the allied colloid fire example discussed earlier. in relation to assess potential chemical hazards, how could the incident have been avoided or mitigated? think about: • the hazard categories of the substances involved; • their compatibility and segregation arrangements; • the quantities likely to be stored; • sources of ignition or thermal decomposition (for thermally unstable compounds); • the impact tackling the fire may have on the environment (pollution). learner activity correct close close close close close close low current and high body resistance. low current and high body resistance. low current and high body resistance. low current and high body resistance. low current and high body resistance. low current and high body resistance. learning check - quiz q 1 the severity of injury received as a result of contact with electricity is minimised by: incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct q1. the severity of injury received as a result of contact with electricity is minimised by: high current and low body resistance. high current and low body resistance. high current and low body resistance. high current and low body resistance. high current and low body resistance. high current and low body resistance. low current and high voltage. low current and high voltage. low current and high voltage. low current and high voltage. low current and high voltage. low current and high voltage. low current and high body resistance. low current and high body resistance. low current and high body resistance. low current and high body resistance. low current and high body resistance. low current and high body resistance. high current and high voltage. high current and high voltage. high current and high voltage. high current and high voltage. high current and high voltage. high current and high voltage. quiz submit submit submit submit submit submit correct close close close close close close where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. learning check - quiz q 2 what is saturated steam? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct q2. what is saturated steam? where all the water has been converted to steam. where all the water has been converted to steam. where all the water has been converted to steam. where all the water has been converted to steam. where all the water has been converted to steam. where all the water has been converted to steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. where some liquid water is still retained in the steam. steam under very high pressure. steam under very high pressure. steam under very high pressure. steam under very high pressure. steam under very high pressure. steam under very high pressure. steam with a temperature in excess of 200˚c. steam with a temperature in excess of 200˚c. steam with a temperature in excess of 200˚c. steam with a temperature in excess of 200˚c. steam with a temperature in excess of 200˚c. steam with a temperature in excess of 200˚c. quiz submit submit submit submit submit submit correct close close close close close close 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. learning check - quiz q 3 legionellae bacteria grow at temperatures between: incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct q3. legionellae bacteria grow at temperatures between: -10°c and -5°c. -10°c and -5°c. -10°c and -5°c. -10°c and -5°c. -10°c and -5°c. -10°c and -5°c. 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. 20°c and 55°c. 60°c and 70°c. 60°c and 70°c. 60°c and 70°c. 60°c and 70°c. 60°c and 70°c. 60°c and 70°c. 70°c and 100°c. 70°c and 100°c. 70°c and 100°c. 70°c and 100°c. 70°c and 100°c. 70°c and 100°c. quiz submit submit submit submit submit submit correct close close close close close close closing of drain valves. closing of drain valves. closing of drain valves. closing of drain valves. closing of drain valves. closing of drain valves. learning check - quiz q 4 one control adopted for safe start-up of plant is: incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct q4. one control adopted for safe start-up of plant is: closing of all valves. closing of all valves. closing of all valves. closing of all valves. closing of all valves. closing of all valves. closing of drain valves. closing of drain valves. closing of drain valves. closing of drain valves. closing of drain valves. closing of drain valves. opening of all valves. opening of all valves. opening of all valves. opening of all valves. opening of all valves. opening of all valves. opening of drain valves. opening of drain valves. opening of drain valves. opening of drain valves. opening of drain valves. opening of drain valves. quiz submit submit submit submit submit submit correct close close close close close close functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. learning check - quiz q 5 in terms of safety critical performance standards, what does the abbreviation ‘farsi’ stand for? incorrect that is incorrect. please try again. try again try again try again try again try again try again incorrect you did not select the correct response. see answer see answer see answer see answer see answer see answer incorrect correct that's right! you selected the correct response. continue continue continue continue continue continue correct q5. in terms of safety critical performance standards, what does the abbreviation ‘farsi’ stand for? functionality, availability, resource, survivability, interdependency. functionality, availability, resource, survivability, interdependency. functionality, availability, resource, survivability, interdependency. functionality, availability, resource, survivability, interdependency. functionality, availability, resource, survivability, interdependency. functionality, availability, resource, survivability, interdependency. functionality, asset integrity, reliability, survivability, interdependency. functionality, asset integrity, reliability, survivability, interdependency. functionality, asset integrity, reliability, survivability, interdependency. functionality, asset integrity, reliability, survivability, interdependency. functionality, asset integrity, reliability, survivability, interdependency. functionality, asset integrity, reliability, survivability, interdependency. functionality, asset integrity, reliability, systemic, interdependency. functionality, asset integrity, reliability, systemic, interdependency. functionality, asset integrity, reliability, systemic, interdependency. functionality, asset integrity, reliability, systemic, interdependency. functionality, asset integrity, reliability, systemic, interdependency. functionality, asset integrity, reliability, systemic, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. functionality, availability, reliability, survivability, interdependency. quiz submit submit submit submit submit submit element 3: summary 3.1 operating procedures 3.2 safe start-up and shut-down 3.3 safety critical performance standards 3.4 utilities 3.5 electricity/static electricity 3.6 dangerous substances 3.7 reaction hazards 3.8 bulk storage operations end of element 3 <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Explain that the qualification consists of one unit. Unit PSM1 is divided into 4 elements. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Explain that the qualification consists of one unit. Unit PSM1 is divided into 4 elements. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='15pt' style="font-size:15pt;" color='#000000'>Designing and operating safe chemical reaction processes HSG 143.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>First, explain the connection with SOE - that operating procedures help keep the process within the SOE.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Some reasons: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Plant and process controls may be turned off or adjusted for the shut-down.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Never really know the full status of the process/plant.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>May not be able to plan for every contingency.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Plant and process needs to be restored to its steady state and this will require variations from normal operating status.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Different ways to define performance standard requirements for Safety Critical Elements common one is &#39;</font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><i>FARSI</i></font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>&#39;: </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>This is closely related to the previous ‘Availability’</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#404040'>Describes the properities and characteristics of the SCE when operating under specified conditions. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Ask delegates to suggest dependencies for the three.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>E.g. blowdown depends on detection and valve operation. Deluge depends on water (foam) supply and detection and valves, emergency shutdown depends on detection/control systems and valve operation which depends on power supply.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Boiling point of water is 100&#176;C at standard pressure but increases with pressure. So, possible to have steam above 100&#176;C.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Problems: increased erosion and possible corrosion. Entrained water flowing through control valves, flowmeters and rotating or reciprocating equipment significantly affects performance and can eventually lead to an inefficient system and plant downtime.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Suitable for being transferred long distances through pipework or driving equipment such as turbines. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Thermal expansion – flexibility built into pipelines/vessels by using expansion joints or expanding sections that compensate for the thermal movement. Other design features (including bellows) can also be used to allow the material to expand without causing a rupture. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Water hammer may occur during start up or during variable conditions</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Special care during start up and shut down - steam traps may not work and water carryover into the system is likely. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Special care during start up and shut down - steam traps may not work and water carryover into the system is likely. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>SOP – standard operating procedure</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>Vessel pressurised with water (typically 150% of designed operational pressure). </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Two forms:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>planktonic – “floating in water” </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Sessile – “stationary “ in biofilm. Once formed, a biofilm can be very difficult to remove.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Risk of legionellosis- inhalation of 5&#181; size water droplets. (aerosol) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Cooling Tower.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Basically works by subjecting hot water (from condensers, etc.) to high air flow.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Water cools and at same time aerosol forms.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>If water quality and tower structure not maintained Legionella will flourish </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Risk also exists wherever sparge pipes are used in plant and process systems to create sprays or mists, </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>includes firefighting and deluge systems; </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>the risk is lower if the water temperatures is outside the Legionella growth region. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>This may not be the case in hot weather. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Drift eliminators - these are fitted in the top (or side) of the tower and force the water which has been forced out to fall back into the tower.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Nitrogen and Argon are already available in natural air - relatively inexpensive to purify and manufacture. Carbon dioxide - readily available. These three gases tend to be the ones used in process plants. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Nitrogen is also used as a liquid for cooling purposes and is stored in large quantities in liquid form.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Main danger is asphyxiation – removing of reducing the oxygen available in air </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Nitrogen and Argon are already available in natural air - relatively inexpensive to purify and manufacture. Carbon dioxide - readily available. These three gases tend to be the ones used in process plants. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Nitrogen is also used as a liquid for cooling purposes and is stored in large quantities in liquid form.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Main danger is asphyxiation – removing of reducing the oxygen available in air </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Low oxygen concentrations create disorientation, dizziness and ultimately death as the level of oxygen reduces. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Testing to both identify the presence of the gas and also the level of oxygen in the air are imperative,</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>(carbon dioxide is required to stimulate the lungs to breath). </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Nitrogen is the more common gas used.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>A pad-depad valve is used to adjust the amount of inert gas in the head space. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Pad depad As the head space gets bigger the valve opens introducing the inerting gas. When the head space gets smaller (as the tank is filled) the other part of the valve opens allowing the inerting gas to return to its storage vessel </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Show short video: https://www.youtube.com/watch?v=o9C-G6x2ALc</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Highlight hazards of asphyxiation and burns again .video on pipe freezing </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>For example, routing of a nitrogen fed control pipe work to a control room may expose the operators to an oxygen reduced atmosphere if there is a fugitive leak (actual case).</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use the above diagram to explain the basics of electrical circuits</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Electricity in a very basic sense involves the flow of electrons, the negatively charged part of atoms, from one place to another through a conductor. When the two poles (or terminals) of a battery are connected to a metal wire (or other electrically conductive material) to make a &#39;circuit&#39;, it causes a current to flow. The current flows due to the movement of electrons through the wire, &#39;pushed&#39; along by the voltage (also called the &#39;potential difference&#39;) between the two poles. You will have noticed that the poles of a battery are labelled as positive (+) and negative (-). By convention, current flows from positive to negative (but in fact the electrons flow in the opposite direction). The potential difference is measured in volts and the current is measured in amps. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>When connected to a battery to make a circuit, some materials are better conductors of electricity than others (i.e. flow is easier through some materials than others). We describe this using the property &#39;resistance&#39;. A good conductor has a low resistance, e.g. copper; a poor conductor has a high resistance and is known as an ‘insulator’, e.g. glass, plastics, dry wood, rubber.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use the above diagram to explain the basics of electrical circuits</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Electricity in a very basic sense involves the flow of electrons, the negatively charged part of atoms, from one place to another through a conductor. When the two poles (or terminals) of a battery are connected to a metal wire (or other electrically conductive material) to make a &#39;circuit&#39;, it causes a current to flow. The current flows due to the movement of electrons through the wire, &#39;pushed&#39; along by the voltage (also called the &#39;potential difference&#39;) between the two poles. You will have noticed that the poles of a battery are labelled as positive (+) and negative (-). By convention, current flows from positive to negative (but in fact the electrons flow in the opposite direction). The potential difference is measured in volts and the current is measured in amps. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>When connected to a battery to make a circuit, some materials are better conductors of electricity than others (i.e. flow is easier through some materials than others). We describe this using the property &#39;resistance&#39;. A good conductor has a low resistance, e.g. copper; a poor conductor has a high resistance and is known as an ‘insulator’, e.g. glass, plastics, dry wood, rubber.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use the above diagram to explain the basics of electrical circuits</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Electricity in a very basic sense involves the flow of electrons, the negatively charged part of atoms, from one place to another through a conductor. When the two poles (or terminals) of a battery are connected to a metal wire (or other electrically conductive material) to make a &#39;circuit&#39;, it causes a current to flow. The current flows due to the movement of electrons through the wire, &#39;pushed&#39; along by the voltage (also called the &#39;potential difference&#39;) between the two poles. You will have noticed that the poles of a battery are labelled as positive (+) and negative (-). By convention, current flows from positive to negative (but in fact the electrons flow in the opposite direction). The potential difference is measured in volts and the current is measured in amps. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>When connected to a battery to make a circuit, some materials are better conductors of electricity than others (i.e. flow is easier through some materials than others). We describe this using the property &#39;resistance&#39;. A good conductor has a low resistance, e.g. copper; a poor conductor has a high resistance and is known as an ‘insulator’, e.g. glass, plastics, dry wood, rubber.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Using this relationship it is thus possible to work out a value of one of the elements if we know the other two. By adjusting any of these the electrical supply can be modified to fit certain applications. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Electricity in process plants generally involves the application of low resistant circuits at high voltage for power and high resistant circuits for heating applications.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>From V=IR equation it can be seen that a high voltage with a low resistance requires a high current. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>High current is dangerous. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Safety: the human body is generally a good conductor when earthed; </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>But comparatively low voltages can cause injury. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>For example, voltages greater than 50 V applied across dry, unbroken human skin can cause heart fibrillation if they produce electric currents that pass through the chest. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>The amount of current will reflect both the source of electricity as well as the part of the body which comes into contact with the power source. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Dry skin offers more resistance to a current than wet skin. If the current is sufficient it will do damage. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Electricity in process plants generally involves the application of low resistant circuits at high voltage for power and high resistant circuits for heating applications.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>From V=IR equation it can be seen that a high voltage with a low resistance requires a high current. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>High current is dangerous. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Safety: the human body is generally a good conductor when earthed; </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>But comparatively low voltages can cause injury. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>For example, voltages greater than 50 V applied across dry, unbroken human skin can cause heart fibrillation if they produce electric currents that pass through the chest. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>The amount of current will reflect both the source of electricity as well as the part of the body which comes into contact with the power source. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Dry skin offers more resistance to a current than wet skin. If the current is sufficient it will do damage. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Electricity in process plants generally involves the application of low resistant circuits at high voltage for power and high resistant circuits for heating applications.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>From V=IR equation it can be seen that a high voltage with a low resistance requires a high current. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>High current is dangerous. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Safety: the human body is generally a good conductor when earthed; </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>But comparatively low voltages can cause injury. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>For example, voltages greater than 50 V applied across dry, unbroken human skin can cause heart fibrillation if they produce electric currents that pass through the chest. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>The amount of current will reflect both the source of electricity as well as the part of the body which comes into contact with the power source. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Dry skin offers more resistance to a current than wet skin. If the current is sufficient it will do damage. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Localised surface burns, (point of entry and exit from the body).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Deep tissue burns cardiac arrhythmia (the heart does not beat properly and blood is lost to the brain and vital organs). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>The nature of the damage depends on the path that the current takes through the body. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>As resistance builds up energy is released in the form of heat. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>This may result in internal burns to deep tissue, e.g. burns to the lungs. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Some cases not be survivable.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Longer exposures at even relatively low voltages can be just as dangerous as short exposures at higher voltages. Low voltage does </font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><i>not</i></font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> imply low hazard. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Temperatures are generally very high - perhaps 20,000 to 30,000 &#176;C. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>The electricity continues to follow its path and in doing so causes the intervening non-conducting material - usually air - to change properties, with the result that a massive current is produced. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>E.g. electric powered trains cross tracks and a brief flash of high intensity light is emitted when the close connection between train and live rail is temporarily broken. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sparks caused are, in a many respects, similar to an arc but involve much less power and limited ionisation of the surrounding air; an arc is a very large spark, but definitions are unclear and vary. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Temperatures are generally very high - perhaps 20,000 to 30,000 &#176;C. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>The electricity continues to follow its path and in doing so causes the intervening non-conducting material - usually air - to change properties, with the result that a massive current is produced. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>E.g. electric powered trains cross tracks and a brief flash of high intensity light is emitted when the close connection between train and live rail is temporarily broken. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sparks caused are, in a many respects, similar to an arc but involve much less power and limited ionisation of the surrounding air; an arc is a very large spark, but definitions are unclear and vary. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>A useful form of arcing is that used in welding where the high intensity heat created is able to melt metal.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Low-energy arcs can cause violent explosions in atmospheres that contain flammable gases, vapours, or combustible dusts.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use of any electrical equipment in potential flammable or explosive atmospheres can give rise to sparks. The designation of at risk areas (e.g. where volatiles may be present) and the mandatory use of appropriate intrinsically safe equipment is mandatory. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sparking also occurs with electrostatic discharge – considered later</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>When shut down or start-up creates a gap across the switching which may induce an arc if not correctly controlled. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Dust/debris, especially in medium and high voltage systems in contact areas may result in arcing. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Condensation/corrosion may affect electrical systems and give rise to a possibility of shorting and sparks or arcing. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>MOC – management of change</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'> </textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The name is from the idea that the electricity is</font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b><i> not </i></b></font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>moving. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tribocharging: Although this is termed friction it is actually the pulling of electrons from one material to another that creates the charge. It is friction at interfaces on a microscopic scale. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tribocharging: Although this is termed friction it is actually the pulling of electrons from one material to another that creates the charge. It is friction at interfaces on a microscopic scale. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Many of these effects occur in process settings. They may occur between:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>• Liquid-liquid</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>• Solid-liquid</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>• Solid-solid</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>• Gas-liquid</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>• Gas-solid</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Give examples – flowing fluids in pipe lines. Volatiles discharge from tanks/vessels . Dust on conveyors, etc. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Spark discharges: these result where a non–conductive (insulated) material (e.g. plastic) comes into proximity with a charged material, which discharges across an air gap, heating the air to high enough temperatures to cause it to glow, e.g. metal flange on a glass pipe (where the metal is insulated by the glass and is therefore non-conductive) or a person insulated from earth by shoes or carpet and touches their finger to charged object, such as a door knob). Occurs between conductors which are not electrically connected. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Corona discharge: often found in high voltage systems where a point electrode is created and sparking occurs as a result of the ions in the surrounding air being energised, e.g. in generators, transformers and capacitors. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Brush discharge: like a corona discharge but results from a blunt electrode and the discharge is therefore wider. Brush discharges may occur between an insulating material and a conductor</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>or between two insulating materials.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Propagating brush discharge: results from thin insulating films in close contact with a conductor. The discharge happens at several points of the surface.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Conical pile discharge (Maurer): this happens when solid material (e.g. dusts) is poured into a container forming conical shape in a the presence of charged air. The sliding of the material in the air causes charge to develop which is then discharged via the top of the “cone”, e.g. : filling of highly insulating bulk solids into silos and containers.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> Spark discharges can only occur between materials which are not electrically connected – so the idea is to connect them so that they are at the same potential</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Brush discharges, as they arise from the use of insulating materials, can only be avoided by either not using such materials, which is often difficult, or by reducing the size of the surface. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Uninterruptible Power Supply (UPS) needs to be required properly sized and maintained. This may also be used to assist in allowing for power fluctuations. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Off line: offline system takes power from the mains and then stores it in a battery. It remains disconnected from the internal distribution system until there is a demand. Switching on can take 25 milliseconds, which may be significant for critical control functions. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Online: online approach is used where electrical isolation is necessary or for equipment that is sensitive to fluctuations in power supply. It is generally used for high-power applications. When the external power source fails, the inverter (which is permanently connected) drops out and power is continuously supplied. When external power is restored the rectifier resumes charging the batteries.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Line interactive: the line interactive approach is an online approach which selectively taps off from the transformer under varying power conditions. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>This may result in small loses of power as the switchover is made. There is typically a 2 to 4 milliseconds delay during the transfer from AC power to battery backup power.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>The choice of approach depends on cost, requirements and functionality. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Off line: offline system takes power from the mains and then stores it in a battery. It remains disconnected from the internal distribution system until there is a demand. Switching on can take 25 milliseconds, which may be significant for critical control functions. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Online: online approach is used where electrical isolation is necessary or for equipment that is sensitive to fluctuations in power supply. It is generally used for high-power applications. When the external power source fails, the inverter (which is permanently connected) drops out and power is continuously supplied. When external power is restored the rectifier resumes charging the batteries.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Line interactive: the line interactive approach is an online approach which selectively taps off from the transformer under varying power conditions. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>This may result in small loses of power as the switchover is made. There is typically a 2 to 4 milliseconds delay during the transfer from AC power to battery backup power.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>The choice of approach depends on cost, requirements and functionality. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Loss to main power can be very serious, both for safety and production. The loss of power fro even a few seconds can cause microprocessors to fail. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>UPS is battery powered with limited life.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Need to have back up generators </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Power surges also need to be compensated for and brownout, or power sag. A power surge may occur when the external supply is restored.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sag may occur due to grid over load and supplier moderates supply. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Maintenance and testing and are fit for purpose when required in an emergency. A fuel supply system that relies on an external supply may be vulnerable particularly of it includes a reliance on electrical power (e.g. Fuel pumps on a diesel system).</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Do this starter exercise in small groups/pairs and share findings with the whole group.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Gases </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><i>state of matter which at atmospheric pressure (at standard temperature and pressure (STP) ) exists in a form which has no defined shape or volume and will uniformly fill the shape of any container it is placed in</i></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Gases particles may be single atoms, single molecules or a mixture, e.g. Ar, N2, CO2. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>reactive or non-reactive. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>heavier of lighter than air. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Gases when pressurised form liquids.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Are vapours gases? </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>(Often called gases, but not strictly so, is the vapour which exists above a liquid. A vapour is not a state of matter but rather the result of the liquid and gaseous states coexisting at equilibrium at STP. In process safety terms, although there is a difference, it is often usual to refer to gas and vapours as being the same. They exhibit the same properties. Vapour usually results from boiling or evaporation. )</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Liquids </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><i>substances which at STP have a fixed volume but take the shape of the container they are in</i></font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> create a vapour at certain temperatures and when this occurs at STP they are often termed as </font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>volatiles</b></font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>. This indicates that above the liquid (open container or head space) the liquid is in its gaseous form</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Solids</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>both a fixed shape and size and retain their shape and volume. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>They do not flow. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Solids may form large objects or exist as discrete small objects such as dusts and powders. Each particle of a powder retains its shape, even though reference is made to “free flowing” when it is poured- e.g. sugar</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'> </textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>STP = standard temperature and pressure</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cross reference to inert gases covered earlier. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Flammable liquids (see later).</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The reason carbonaceous dusts are so vulnerable to fire and explosion is because if they become mixed with air they present a very large surface area creating a flammable atmosphere. In many operations involving powders, it is essential to mix them with some other reactant. In doing so the powder becomes dispersed in air and may therefore become flammable or explosive. This risk can often be overcome by inerting the atmosphere in the mixing vessel. Likewise, operations such as sieving and similar activities create a dust cloud (and note - also possibly an electrostatic charge) making them a potential risk for fire/explosion. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The reason carbonaceous dusts are so vulnerable to fire and explosion is because if they become mixed with air they present a very large surface area creating a flammable atmosphere. In many operations involving powders, it is essential to mix them with some other reactant. In doing so the powder becomes dispersed in air and may therefore become flammable or explosive. This risk can often be overcome by inerting the atmosphere in the mixing vessel. Likewise, operations such as sieving and similar activities create a dust cloud (and note - also possibly an electrostatic charge) making them a potential risk for fire/explosion. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Substances are categorised by: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- the minimum energy required to ignite it (MIE); and </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- the concentration of oxygen (air) which will support the ignition and subsequent fire/explosion.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Flash Point – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>the lowest temperature at which sufficient vapour is given off to ‘flash’, i.e. ignite momentarily (not continue to burn), when a source of ignition is applied to that vapour.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Vapour Density – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>vapour density expresses the mass per unit volume of vapour, i.e. its weight. It is measured relative to hydrogen (air in USA).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Vapour Pressure – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>the pressure exerted by a vapour in equilibrium with its liquid (or solid) state.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Flash Point – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>the lowest temperature at which sufficient vapour is given off to ‘flash’, i.e. ignite momentarily (not continue to burn), when a source of ignition is applied to that vapour.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Vapour Density – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>vapour density expresses the mass per unit volume of vapour, i.e. its weight. It is measured relative to hydrogen (air in USA).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Vapour Pressure – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>the pressure exerted by a vapour in equilibrium with its liquid (or solid) state.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Flash Point – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>the lowest temperature at which sufficient vapour is given off to ‘flash’, i.e. ignite momentarily (not continue to burn), when a source of ignition is applied to that vapour.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Vapour Density – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>vapour density expresses the mass per unit volume of vapour, i.e. its weight. It is measured relative to hydrogen (air in USA).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 57px'><textformat leading='5' tabstops='[0, 57, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'><b>Vapour Pressure – </b></font><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>the pressure exerted by a vapour in equilibrium with its liquid (or solid) state.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'> <font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>General discussion on what students think a chemical reaction is </b></font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>– cover general characteristics such as conversion of one ‘substance’ into something else by combining with other chemicals. Explore everyday examples, such as combustion/burning, ‘rusting’ of iron, neutralisation (acid + alkali). Cover issues such as physical changes that may occur (sometimes gases are produced from solids/liquids during the reaction), including the production of heat (exothermic). These aspects will be covered in more detail later – so this is a springboard for provoking thought.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Lead into a discussion of wide use of chemical reactions in the process industry:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Process industries rely upon chemical reactions to produce new materials </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Various activities involved : mixing, stirring, heating, cooling.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Basic process involves taking raw material from storage, undertaking the reaction(s), isolating the product and preparing it for use. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>3 types of basic process:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>- batch, </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>- semi-batch, or </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;display: inline-block; text-align:left; min-width: 0px; margin-left: 0px;" color='#000000'>•</font><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'> continuous operations.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>The control of the reaction, both to ensure the correct product is made and to ensure safety, requires an understanding of the chemical reaction itself. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Safety of chemical reactions is a key subject for the chemical industry.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'><b>Influences on chemical reaction rate </b></font><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>– include concentration, physical form (how intimately the reactants mix), temperature, pressure, presence of “impurities” (especially what we call ‘catalysts’). </font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Central to understanding reactions is to understand energy.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Energy is mostly controlled by temperature and pressure. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Reactions can be further facilitated by the use of catalysts. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>Cover some of these issues next.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Explain the graph. This is a generalised trend, and assumes all other things being equal (e.g. constant reactant concentrations, constant pressure, etc.) In reality, reactants will be consumed, the rate will then slow and halt at some point.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Chemical reactions involve energy to bring about the required changes.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In the majority of cases this energy is provided by raising the temperature. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In simple terms a chemical reaction results from the colliding together of the particles of two or more different chemicals. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Low temperature insufficient energy to react with each other.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>As the temperature increases more energy is imparted to the particles and eventually (at what is known as the activation energy) there are sufficient highly energised particles to cause the reaction to take place.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In very general terms, each raise of 10&#176; causes a doubling in the rate of reaction. But for the most part this applies to manufacturing processes. Thus by adjusting temperature it is possible to control the speed or rate of reaction.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>This does not apply to all reactions, e.g. mixing an acid and an alkali is an instantaneous reaction which does not require energy in the form of heat to make it happen. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Explain the graph. This is a generalised trend, and assumes all other things being equal (e.g. constant reactant concentrations, constant pressure, etc.) In reality, reactants will be consumed, the rate will then slow and halt at some point.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Chemical reactions involve energy to bring about the required changes.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In the majority of cases this energy is provided by raising the temperature. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In simple terms a chemical reaction results from the colliding together of the particles of two or more different chemicals. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Low temperature insufficient energy to react with each other.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>As the temperature increases more energy is imparted to the particles and eventually (at what is known as the activation energy) there are sufficient highly energised particles to cause the reaction to take place.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In very general terms, each raise of 10&#176; causes a doubling in the rate of reaction. But for the most part this applies to manufacturing processes. Thus by adjusting temperature it is possible to control the speed or rate of reaction.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>This does not apply to all reactions, e.g. mixing an acid and an alkali is an instantaneous reaction which does not require energy in the form of heat to make it happen. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Explain the graph. This is a generalised trend, and assumes all other things being equal (e.g. constant reactant concentrations, constant pressure, etc.) In reality, reactants will be consumed, the rate will then slow and halt at some point.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Chemical reactions involve energy to bring about the required changes.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In the majority of cases this energy is provided by raising the temperature. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In simple terms a chemical reaction results from the colliding together of the particles of two or more different chemicals. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Low temperature insufficient energy to react with each other.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>As the temperature increases more energy is imparted to the particles and eventually (at what is known as the activation energy) there are sufficient highly energised particles to cause the reaction to take place.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In very general terms, each raise of 10&#176; causes a doubling in the rate of reaction. But for the most part this applies to manufacturing processes. Thus by adjusting temperature it is possible to control the speed or rate of reaction.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>This does not apply to all reactions, e.g. mixing an acid and an alkali is an instantaneous reaction which does not require energy in the form of heat to make it happen. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>For gases, increasing pressure is the way you increase concentration (the gas equation P = nRT/V, where n/V is number of moles of a gas per unit volume (i.e. the concentration)).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>Pressure increase has a similar effect to temperature. Application of pressure reduces the space (volume) between the particles and thereby increases the likelihood that collisions will occur. Speed of reaction controlled by pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>In many cases a combination of temperature and pressure adjustment is used. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>For gases, increasing pressure is the way you increase concentration (the gas equation P = nRT/V, where n/V is number of moles of a gas per unit volume (i.e. the concentration)).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>Pressure increase has a similar effect to temperature. Application of pressure reduces the space (volume) between the particles and thereby increases the likelihood that collisions will occur. Speed of reaction controlled by pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='26pt' style="font-size:26pt;" color='#000000'>In many cases a combination of temperature and pressure adjustment is used. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>This shows an energy diagram for a typical exothermic reaction – where heat is given out (the products have lower energy than the reactants).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>A catalyst is a medium put into a reaction vessel which changes the pathway (mechanism) of a reaction so that particles are forced into closer proximity. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>Increases the speed of a reaction by lowering the activation energy. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>Catalysts are not destroyed or changed during a reaction:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>- Generally reusable.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>- May suffer from poisoning by contamination with undesired trace substances in the reaction mixture.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>This shows an energy diagram for a typical exothermic reaction – where heat is given out (the products have lower energy than the reactants).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>A catalyst is a medium put into a reaction vessel which changes the pathway (mechanism) of a reaction so that particles are forced into closer proximity. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>Increases the speed of a reaction by lowering the activation energy. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>Catalysts are not destroyed or changed during a reaction:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>- Generally reusable.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='20.5pt' style="font-size:20.5pt;" color='#000000'>- May suffer from poisoning by contamination with undesired trace substances in the reaction mixture.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>An out of control exothermic reaction.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>If the heat produced by the reaction is not removed fast enough the reaction speeds up.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The reaction may then “runaway”.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Mainly applies to batch processes.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Introduce Seveso here – video ? </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Containment</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Correct design and construction of the vessel to withstand the pressure and temperature.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Problem for vapour producing reactions - pressure rise can be too great to be effectively resisted. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cost of building vessels with sufficiently thick walls may be prohibitive. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Encase in concrete or a steel/concrete bunker.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Containment is advantageous as there is no venting and the control is passive requiring no intervention.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Crash cooling</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Emergency or crash cooling involves the activation of additional cooling to the reactor.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use some other cooling process, e.g. reflux condenser or an external heat exchanger. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Pump a refrigerant though the reactor coils or into the jacket. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Issue - temperature too low, material will solidify making the situation worse.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sometimes the term crash cooling is also used to describe the addition of water (other cooling agent) to the reactor, which is more properly a form of quenching. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Drowning and quenching</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Supplying a significant volume of cold non-reactive agent into the reactor - usually water direct into reactor vessel from gravity feed tank discharging into reactor via temperature activated valve. Or dump into a tank of coolant, achieving the same effect. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Add non-reactive diluent.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Active quenching: use an agent which can alter the reaction taking place by inhibiting the reaction. (It needs to be carefully chosen so that all possible circumstances are accounted for, but provides a substitute for a direct acting inhibitor.) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Emergency Venting</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Reactor vessels are fitted with a vent to release excess pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Vents may not be sized to take the full over pressure caused by the reaction. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The use of the emergency pressure relief may need to be supplemented and in any event the discharge should go via an emergency effluent handling or discharge system such as vapour-liquid separator, (knock out drum). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bursting disk - pressure release is set at a predetermined level so that venting takes place before the runaway has become critical. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Dumping involves emptying the reactor and sending the contents for treatment, e.g. scrubber to separate out and recover materials or flared off through a flare stack.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>It is not always possible to design a protective system to cope with the full consequences of a runaway reaction. The events of Seveso show this to be true. Hence the importance of inherent safety being at the top of the hierarchy of process safety risk control (see element 2).&#160;</font> <font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>&#160;</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Containment</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Correct design and construction of the vessel to withstand the pressure and temperature.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Problem for vapour producing reactions - pressure rise can be too great to be effectively resisted. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cost of building vessels with sufficiently thick walls may be prohibitive. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Encase in concrete or a steel/concrete bunker.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Containment is advantageous as there is no venting and the control is passive requiring no intervention.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Crash cooling</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Emergency or crash cooling involves the activation of additional cooling to the reactor.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use some other cooling process, e.g. reflux condenser or an external heat exchanger. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Pump a refrigerant though the reactor coils or into the jacket. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Issue - temperature too low, material will solidify making the situation worse.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sometimes the term crash cooling is also used to describe the addition of water (other cooling agent) to the reactor, which is more properly a form of quenching. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Drowning and quenching</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Supplying a significant volume of cold non-reactive agent into the reactor - usually water direct into reactor vessel from gravity feed tank discharging into reactor via temperature activated valve. Or dump into a tank of coolant, achieving the same effect. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Add non-reactive diluent.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Active quenching: use an agent which can alter the reaction taking place by inhibiting the reaction. (It needs to be carefully chosen so that all possible circumstances are accounted for, but provides a substitute for a direct acting inhibitor.) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Emergency Venting</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Reactor vessels are fitted with a vent to release excess pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Vents may not be sized to take the full over pressure caused by the reaction. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The use of the emergency pressure relief may need to be supplemented and in any event the discharge should go via an emergency effluent handling or discharge system such as vapour-liquid separator, (knock out drum). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bursting disk - pressure release is set at a predetermined level so that venting takes place before the runaway has become critical. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Dumping involves emptying the reactor and sending the contents for treatment, e.g. scrubber to separate out and recover materials or flared off through a flare stack.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>It is not always possible to design a protective system to cope with the full consequences of a runaway reaction. The events of Seveso show this to be true. Hence the importance of inherent safety being at the top of the hierarchy of process safety risk control (see element 2).&#160;</font> <font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>&#160;</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Containment</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Correct design and construction of the vessel to withstand the pressure and temperature.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Problem for vapour producing reactions - pressure rise can be too great to be effectively resisted. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cost of building vessels with sufficiently thick walls may be prohibitive. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Encase in concrete or a steel/concrete bunker.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Containment is advantageous as there is no venting and the control is passive requiring no intervention.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Crash cooling</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Emergency or crash cooling involves the activation of additional cooling to the reactor.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use some other cooling process, e.g. reflux condenser or an external heat exchanger. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Pump a refrigerant though the reactor coils or into the jacket. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Issue - temperature too low, material will solidify making the situation worse.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sometimes the term crash cooling is also used to describe the addition of water (other cooling agent) to the reactor, which is more properly a form of quenching. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Drowning and quenching</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Supplying a significant volume of cold non-reactive agent into the reactor - usually water direct into reactor vessel from gravity feed tank discharging into reactor via temperature activated valve. Or dump into a tank of coolant, achieving the same effect. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Add non-reactive diluent.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Active quenching: use an agent which can alter the reaction taking place by inhibiting the reaction. (It needs to be carefully chosen so that all possible circumstances are accounted for, but provides a substitute for a direct acting inhibitor.) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Emergency Venting</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Reactor vessels are fitted with a vent to release excess pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Vents may not be sized to take the full over pressure caused by the reaction. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The use of the emergency pressure relief may need to be supplemented and in any event the discharge should go via an emergency effluent handling or discharge system such as vapour-liquid separator, (knock out drum). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bursting disk - pressure release is set at a predetermined level so that venting takes place before the runaway has become critical. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Dumping involves emptying the reactor and sending the contents for treatment, e.g. scrubber to separate out and recover materials or flared off through a flare stack.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>It is not always possible to design a protective system to cope with the full consequences of a runaway reaction. The events of Seveso show this to be true. Hence the importance of inherent safety being at the top of the hierarchy of process safety risk control (see element 2).&#160;</font> <font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>&#160;</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Containment</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Correct design and construction of the vessel to withstand the pressure and temperature.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Problem for vapour producing reactions - pressure rise can be too great to be effectively resisted. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cost of building vessels with sufficiently thick walls may be prohibitive. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Encase in concrete or a steel/concrete bunker.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Containment is advantageous as there is no venting and the control is passive requiring no intervention.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Crash cooling</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Emergency or crash cooling involves the activation of additional cooling to the reactor.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use some other cooling process, e.g. reflux condenser or an external heat exchanger. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Pump a refrigerant though the reactor coils or into the jacket. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Issue - temperature too low, material will solidify making the situation worse.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sometimes the term crash cooling is also used to describe the addition of water (other cooling agent) to the reactor, which is more properly a form of quenching. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Drowning and quenching</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Supplying a significant volume of cold non-reactive agent into the reactor - usually water direct into reactor vessel from gravity feed tank discharging into reactor via temperature activated valve. Or dump into a tank of coolant, achieving the same effect. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Add non-reactive diluent.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Active quenching: use an agent which can alter the reaction taking place by inhibiting the reaction. (It needs to be carefully chosen so that all possible circumstances are accounted for, but provides a substitute for a direct acting inhibitor.) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Emergency Venting</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Reactor vessels are fitted with a vent to release excess pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Vents may not be sized to take the full over pressure caused by the reaction. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The use of the emergency pressure relief may need to be supplemented and in any event the discharge should go via an emergency effluent handling or discharge system such as vapour-liquid separator, (knock out drum). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bursting disk - pressure release is set at a predetermined level so that venting takes place before the runaway has become critical. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Dumping involves emptying the reactor and sending the contents for treatment, e.g. scrubber to separate out and recover materials or flared off through a flare stack.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>It is not always possible to design a protective system to cope with the full consequences of a runaway reaction. The events of Seveso show this to be true. Hence the importance of inherent safety being at the top of the hierarchy of process safety risk control (see element 2).&#160;</font> <font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>&#160;</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Containment</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Correct design and construction of the vessel to withstand the pressure and temperature.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Problem for vapour producing reactions - pressure rise can be too great to be effectively resisted. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cost of building vessels with sufficiently thick walls may be prohibitive. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Encase in concrete or a steel/concrete bunker.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Containment is advantageous as there is no venting and the control is passive requiring no intervention.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Crash cooling</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Emergency or crash cooling involves the activation of additional cooling to the reactor.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use some other cooling process, e.g. reflux condenser or an external heat exchanger. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Pump a refrigerant though the reactor coils or into the jacket. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Issue - temperature too low, material will solidify making the situation worse.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sometimes the term crash cooling is also used to describe the addition of water (other cooling agent) to the reactor, which is more properly a form of quenching. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Drowning and quenching</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Supplying a significant volume of cold non-reactive agent into the reactor - usually water direct into reactor vessel from gravity feed tank discharging into reactor via temperature activated valve. Or dump into a tank of coolant, achieving the same effect. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Add non-reactive diluent.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Active quenching: use an agent which can alter the reaction taking place by inhibiting the reaction. (It needs to be carefully chosen so that all possible circumstances are accounted for, but provides a substitute for a direct acting inhibitor.) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Emergency Venting</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Reactor vessels are fitted with a vent to release excess pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Vents may not be sized to take the full over pressure caused by the reaction. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The use of the emergency pressure relief may need to be supplemented and in any event the discharge should go via an emergency effluent handling or discharge system such as vapour-liquid separator, (knock out drum). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bursting disk - pressure release is set at a predetermined level so that venting takes place before the runaway has become critical. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Dumping involves emptying the reactor and sending the contents for treatment, e.g. scrubber to separate out and recover materials or flared off through a flare stack.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>It is not always possible to design a protective system to cope with the full consequences of a runaway reaction. The events of Seveso show this to be true. Hence the importance of inherent safety being at the top of the hierarchy of process safety risk control (see element 2).&#160;</font> <font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>&#160;</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Containment</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Correct design and construction of the vessel to withstand the pressure and temperature.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Problem for vapour producing reactions - pressure rise can be too great to be effectively resisted. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cost of building vessels with sufficiently thick walls may be prohibitive. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Encase in concrete or a steel/concrete bunker.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Containment is advantageous as there is no venting and the control is passive requiring no intervention.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Crash cooling</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Emergency or crash cooling involves the activation of additional cooling to the reactor.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use some other cooling process, e.g. reflux condenser or an external heat exchanger. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Pump a refrigerant though the reactor coils or into the jacket. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Issue - temperature too low, material will solidify making the situation worse.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Sometimes the term crash cooling is also used to describe the addition of water (other cooling agent) to the reactor, which is more properly a form of quenching. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Drowning and quenching</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Supplying a significant volume of cold non-reactive agent into the reactor - usually water direct into reactor vessel from gravity feed tank discharging into reactor via temperature activated valve. Or dump into a tank of coolant, achieving the same effect. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Add non-reactive diluent.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Active quenching: use an agent which can alter the reaction taking place by inhibiting the reaction. (It needs to be carefully chosen so that all possible circumstances are accounted for, but provides a substitute for a direct acting inhibitor.) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'><b>Emergency Venting</b></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Reactor vessels are fitted with a vent to release excess pressure.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Vents may not be sized to take the full over pressure caused by the reaction. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>The use of the emergency pressure relief may need to be supplemented and in any event the discharge should go via an emergency effluent handling or discharge system such as vapour-liquid separator, (knock out drum). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bursting disk - pressure release is set at a predetermined level so that venting takes place before the runaway has become critical. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Dumping involves emptying the reactor and sending the contents for treatment, e.g. scrubber to separate out and recover materials or flared off through a flare stack.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='3' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>It is not always possible to design a protective system to cope with the full consequences of a runaway reaction. The events of Seveso show this to be true. Hence the importance of inherent safety being at the top of the hierarchy of process safety risk control (see element 2).&#160;</font> <font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>&#160;</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Similarly, overfilling of vessels intended to separate gases from liquids results in the liquid entering the outlets designed to take the gas phase.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>majority of storage tanks used in the process industries are constructed of plate steel. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>designed to withstand the internal pressure exerted from the contents when filled. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>,weak when exposed to external pressure. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>Incident at the West Fertiliser Company in Texas – 12:31’</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='5' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='27.5pt' style="font-size:27.5pt;" color='#000000'>https://www.youtube.com/watch?v=pdDuHxwD5R4</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Gradual extension of material under a steady tensile stress, more likely to occur at higher temperatures</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>tank or pipe may deform and eventually fracture. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tensile refers to the pulling apart of the metal in a single plane. Another aspect is elasticity which refers to the degree to which the material will return to its former length after stretching. Tensile strength and elasticity decrease with increasing temperature which means that creep is more likely to occur at higher temperatures.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Gradual extension of material under a steady tensile stress, more likely to occur at higher temperatures</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>tank or pipe may deform and eventually fracture. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tensile refers to the pulling apart of the metal in a single plane. Another aspect is elasticity which refers to the degree to which the material will return to its former length after stretching. Tensile strength and elasticity decrease with increasing temperature which means that creep is more likely to occur at higher temperatures.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Stress - tensile or compressive loading placed on a material – it’s the amount of force applied per unit area.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Two broad categories of material:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Ductile- which will deform significantly under stress before they break</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Brittle - which deform very little before they break.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Strain is the deformation (relative change in shape/size)</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>tank being emptied and then refilled will be subject to movement as the structure responds to the variation in the load placed upon it. In pipework at flanges, openings and connections there will be greater loading and therefore more stress.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cyclic stress and plastic strain initiate the cracks while tensile stress is responsible for its initiation and propagation. Plastic- doesn&#39;t return to shape, i.e. not elastic.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Cyclic stress: repeated actions creating stress, e.g. filling/emptying, loading/unloading. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>There is a wide range of issues to consider:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Size and type of tank.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Contents (flammable, toxic, polluting).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Topography (level ground, sloping ground, high level, low level).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Purpose of tank in relation to process (feed stock or product, proximity to point of use).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Land use planning requirements (legal requirements for siting structures). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Total inventory (how much material is being stored).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Whether the tank is underground, above ground or mounded, etc.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- Distance from sensitive areas (populations, environments, etc.)</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>Use the above diagram (this is from HSG176) to point out some of these considerations – concentrating on distance from people, property and other tanks containing dangerous substances.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>Separation distances:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>- Useful to limit spread of fire.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>- Away from site boundary, occupied buildings, sources of ignition and process areas.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>HSG176: for large tanks </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>- Minimum distance from boundaries 15m and between 10m and 15m tanks. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'><i>Does not protect from radiation effects</i></font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>Explosion walls and passive fire protection built into structures. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>Calculation may be necessary to ensure that buildings are robust to withstand worst case scenarios. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>Offsite buildings should be protected by sufficiently large separation distances, but as the Buncefield incident showed, this may not be realistic in practice.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>Other considerations:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>- Location of other storage vessels.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>- Dangerous substances.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>- Vulnerability of process lines.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='13.5pt' style="font-size:13.5pt;" color='#000000'>- The larger the tank, the greater the separation distances required.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='2' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Most tanks will need to be ventilated for various reasons.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tanks above ground should be sited in a well-ventilated unobstructed position separated from the site boundary, occupied buildings, sources of ignition and process areas. This will ensure that any fugitive emissions, spillages, etc. from tanks, transfer facilities, vent pipes, etc. will be readily dispersed in the open air. Consider normal venting - including return of material to process, etc. to avoid loss (inbreathing) and emergency venting, e.g. pressure relief exposure to fire.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Most tanks will need to be ventilated for various reasons.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tanks above ground should be sited in a well-ventilated unobstructed position separated from the site boundary, occupied buildings, sources of ignition and process areas. This will ensure that any fugitive emissions, spillages, etc. from tanks, transfer facilities, vent pipes, etc. will be readily dispersed in the open air. Consider normal venting - including return of material to process, etc. to avoid loss (inbreathing) and emergency venting, e.g. pressure relief exposure to fire.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Over filling serious issue. Filling may be remotely via pipeline or locally from a tanker.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>SIL – Safety Integrity Level</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use Buncefield to highlight the issues.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'> </textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tutor to describe the elements of it using the diagram.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Open to the elements.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Open-topped cylindrical steel shell roof rising and falling with the liquid level. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Roof comprises a deck fittings.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Rim seal system - designed to keep out rain water and prevent vapour emissions. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Typically on a pontoon </font><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>although there are other variants</font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Legs enable the roof to stand about 2m clear of the base (enables internal maintenance and inspection work). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>“Landing” the roof. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Tutor to describe the elements of it using the diagram.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Open to the elements.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Open-topped cylindrical steel shell roof rising and falling with the liquid level. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Roof comprises a deck fittings.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Rim seal system - designed to keep out rain water and prevent vapour emissions. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Typically on a pontoon </font><font face='Calibri' size='16.5pt' style="font-size:16.5pt;" color='#000000'>although there are other variants</font><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Legs enable the roof to stand about 2m clear of the base (enables internal maintenance and inspection work). </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>“Landing” the roof. </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>In one case, firefighting water activated on ESD and one of the pontoons filled with water destabilising the roof deck which sank into condensate in the tank leading to loss of containment.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Image from HSG176.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Used for low vapour pressure high flash point liquids which are stable at atmospheric pressure. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Minimum vapour release as the vapour and air are balanced. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Variations in temperature caused by weather or by product charging at an elevated temperature will be vented though a pressure-vacuum valve. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Cylindrical steel shell with a cone- or dome-shaped roof. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Roof permanently fixed (welded) to the tank shell. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Modern fixed roof designed to be both liquid and vapour tight.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Older tanks may be of a riveted or bolted construction and are not vapour tight.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'><b>Pressure and vacuum hazards</b></font><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'> were introduced earlier. Fixed roof tanks especially are susceptible to external pressure. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='4' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='19pt' style="font-size:19pt;" color='#000000'>Whilst they may be overloaded by overpressurised filling they are more likely to collapse if a vacuum forms internally when they are emptied.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bund: an impervious wall usually concrete, designed to retain the contents of the tank(s) should there be a failure and the contents of the tank released.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Effective to contain any boil over or top loss, which may well discharge like a fountain or spigot, as well as bottom loss and likewise catastrophic failure where the contents will disperse like a tidal wave. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Bunds can be insulated to further protect from effects of temperature, especially fire.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Mention earth bunding and mounds.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Illustration </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Not easy or effective to bond the roof with the shell of the tank as there is a lack of continuity between the roof and the shell.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Begin by outlining how storage of chemicals in the process industry, presents a number for risks: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- The hazardous nature of the stored substances.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- The consequences arising from: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Inadvertent mixing of incompatible chemicals. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Leaking and spillage from containers. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Possible reactions from exposure to elevated temperatures. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Significant release of dust and powders and solvents.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use Allied Colloids fire as a case study:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>https://www.youtube.com/watch?v=G56UyZEL1A4 </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Look at factors needed to assess storage requirements – in small groups. The next few slides take you through some of these issues in more detail.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>How the material will be transported, e.g. in bulk containers, metal drums, fibre drums, Intermediate Bulk Containers (IBCs) , FIBCs (flexible intermediate bulk container (FIBC)), etc. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>This will also include the means of transportation, e.g. fork lift truck, e.g. in bulk containers, metal drums, fibre drums, Intermediate bulk containers (IBCs) , FIBCs (flexible intermediate bulk container (FIBC)), etc. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>This will also include the means of transportation, e.g. fork lift truck, temperature effects, e.g. some substances may degrade at higher temperature or become unstable (relative).</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Vehicle movements (e.g. risk of collision with stored materials or increase chance of spillage).</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Security should not compromise fire safety and a balance sometimes has to be made between the two, e.g. high level venting for fire control may provide an route of entry. Inadvertent incorrect storage of incompatible materials (e.g. in absence of the authorised warehouse personnel someone directs acids to be stored in the alkaline area). </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>l </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Image is taken from HSG71 - illustrative</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>incompatible materials stored separately</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Store hazardous chemicals separately from each other </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>segregated from all other materials</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>(e.g acids and alkalines) </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Requires detailed understanding of chemical and physical properties</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Agan refer to Allied Colloids</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Image is taken from HSG71 - illustrative</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='0' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>This includes normal storage and in release/spill situations. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Initiate discussion to highlight key areas </font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Begin by outlining how storage of chemicals in the process industry, presents a number for risks: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- The hazardous nature of the stored substances.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- The consequences arising from: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Inadvertent mixing of incompatible chemicals. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Leaking and spillage from containers. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Possible reactions from exposure to elevated temperatures. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Significant release of dust and powders and solvents.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use Allied Colloids fire as a case study:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>https://www.youtube.com/watch?v=G56UyZEL1A4 </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Look at factors needed to assess storage requirements – in small groups. The next few slides take you through some of these issues in more detail.</font></textformat></p></html> <html><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Begin by outlining how storage of chemicals in the process industry, presents a number for risks: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- The hazardous nature of the stored substances.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>- The consequences arising from: </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Inadvertent mixing of incompatible chemicals. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Leaking and spillage from containers. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Possible reactions from exposure to elevated temperatures. </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'> - Significant release of dust and powders and solvents.</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Use Allied Colloids fire as a case study:</font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>https://www.youtube.com/watch?v=G56UyZEL1A4 </font></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'></textformat></p><p align='left' style='text-align:left;direction: ltr; padding-left: 0px'><textformat leading='6' tabstops='[0, 48, 96, 144]'><font face='Calibri' size='30pt' style="font-size:30pt;" color='#000000'>Look at factors needed to assess storage requirements – in small groups. The next few slides take you through some of these issues in more detail.</font></textformat></p></html> ALARP means that the risk hasn’t just been reduced, but is now at the lowest level that can be achieved without incurring disproportionate costs (costs can be financial, time, effort and inconvenience). An item of equipment or an area of production plant. The ability of an asset to perform its required function effectively and efficiently whilst protecting health, safety and the environment. Controls that can be put in place between the initiator (the triggering event) to either prevent if from happening or to mitigate the outcome. Also see Bow-Tie model and Hazard realisation. Used with ‘hazard realisation’. As the hazard realisation is worked through then ‘barriers’ can be identified that can be placed between the initiator (the triggering event) to either prevent it from happening or to mitigate the outcome (also known as layers of protection or defence. When these are drawn together this is known as a bow-tie. Hazardous places are classified in terms of zones on the basis of the frequency and duration of the occurrence of an explosive atmosphere: Zones 0-2 relate to gas/vapours/mists and Zones 20-22 to dusts. The ability to undertake responsibilities and to perform activities to a relevant standard, as necessary, to ensure process safety and prevent major accidents. Competence is a combination of knowledge skills and experience and requires a willingness and reliability that work activities will be undertaken in accordance with agreed standards, rules and procedures. A contractor is anyone you get in to work for you who is not an employee. A reaction is called endothermic if energy (heat) is absorbed during the reaction. Used to evaluate the mitigation measures that will operate after an event. The process starts with an initiating event and works forward in time to see what protective measure will operate. Each control will either be a success or a failure and, in this way, branches are built up on tree. A reaction is called exothermic if energy (heat) is released during the reaction. One or more deliberate points of weakness are included in process plant; it they are of suitable size and in the right place, they will safely vent an explosion with the plant. A substance has the risk of exploding in the right mixture with oxygen and if sufficient energy is available. A study often used to brainstorm how a component or a system might fail, the potential effects/consequences of those failures, existing safeguards against those failure modes and whether more should be in place. The property of a substance (usually gas or liquid (or the vapour above the liquid)) to ignite when sufficient energy is applied in the form of heat. The minimum temperature at which a liquid, under specific test conditions, gives off sufficient flammable vapour to ignite momentarily on the application of an ignition source. An advanced risk assessment. It is a very thorough analysis of a process to identify ways in which the process could deviate from its design intention in order that controls can be developed. It is usually chaired by an independent HAZOP leader and involves a multidisciplinary team of designers, engineers, safety professionals, operators and other specialists. A brainstorming activity to identify hazards before changes are made to existing processes and plant (sometimes called a walk-through). In hazard realisation, the assessor looks at ‘the worst-case scenario’ to understand the potential consequences of the hazard so that controls can be implemented in the form of barriers. Reactive measures that look at failures such as the number of injuries, near misses and spills which are reported, or excursions where plant is operated outside of the intended operational envelope. Proactive measurements of conditions that monitor process safety management before something goes wrong and to see if things are operating as intended. The minimum concentration of vapour in air below which propagation of a flame will not occur in the presence of an ignition source. Also referred to as the lowerflammable limit or lower explosive limit. The property of a substance to readily accept electrons from another substance. A formal recorded process used to control work which is identified as potentially hazardous. It is also a means of communication between site/installation management, plant supervisors and operators and those who carry out the hazardous work. Any activity involving a highly hazardous chemical including use, storage, manufacturing, handling, or the on-site movement of such chemicals, or combination of these activities. Any group of vessels that are interconnected, & Separate vessels which are located such that a highly hazardous chemical could be involved in a potential release. The above all considered a single process. A blend of engineering and management skills focused on preventing catastrophic accidents and near misses, particularly structural collapse, explosions, fires and toxic releases associated with loss of containment of energy or dangerous substances such as chemicals and petroleum products. These engineering and management skills exceed those required for managing workplace safety (Adapted from Centre for Chemical Process Safety of the American Institute of Chemical Engineers) The limits of the operating conditions under which a process can take place safely. Typically, process limits are established by setting upper and lower levels for a range of parameters. A document step-by-step instruction on how to conduct specific parts of the operating process. It sets out the way a certain task or activity is done so that mistakes which might lead to a situation where the safe operating envelope could be breached are avoided. The overall purpose of the SOP is to identify and maintain the operating parameters such as pressure limits, temperature range, flow rates etc at the required safe level. The terms used to describe the transfer of information between a shift who are leaving work and incoming new shift. A reaction that is out of control because the rate of heat generation by an exothermic chemical reaction exceeds the rate of cooling available. The maximum concentration of vapour in air above which the propagation of a flame will not occur. Also referred to as the upper flammable limit or the upper explosion limit. In ‘what-if analysis of risk realisation, the assessor asks, 'what-if' and then digs deeper to look at the true potential of an incident.