Process Hazard Review Questions

Use these questions to help identify potential hazards. Answer each question fully, not with a simple “Yes” or “No.” Some questions may not be applicable to the review of a particular process; other questions should be interpreted broadly to include similar materials or equipment in your facility. Consider the questions in terms of all operating modes (e.g., steady state, startup, shutdown, maintenance, and upsets).

  1. Process

    1. Materials and Flowsheet

    2. Unit Siting and Layout

  2. Equipment

    1. Pressure and Vacuum Relief

    2. Piping and Valves

    3. Pumps

    4. Compressors

    5. Reactors

    6. Vessels (Tanks, Drums, Towers, etc.)

    7. Heat Exchangers

    8. Furnaces and Boilers

    9. Instrumentation

    10. Electrical Power

    11. Miscellaneous

  3. Operations

  4. Maintenance

  5. Personnel Safety

    1. Building and Structures

    2. Operating Areas

    3. Yard

  6. Fire Protection

  7. Environmental Protection

  8. Management and Policy Issues

I. Process

A. Materials and Flowsheet

  1. What materials are hazardous (e.g., raw materials, intermediates, products, by-products, wastes, accidental reaction products, combustion products)? Are any prone to form vapor clouds?
    — Which ones are acutely toxic?
    — Which ones are chronically toxic, carcinogenic, mutagenic, or teratogenic?
    — Which ones are flammable?
    — Which ones are combustible?
    — Which ones are unstable, shock-sensitive, or pyrophoric?
    — Which ones have release limits specified by law or regulation?
  2. What are the properties of the process materials? Consider:
    — physical properties (e.g., boiling point, melting point, vapor pressure).
    — acute toxic properties and exposure limits (e.g., IDLH, LD50).
    — chronic toxic properties and exposure limits (e.g., TLV, PEL).
    — reactive properties (e.g., incompatible or corrosive materials, polymerization).
    — combustion properties (e.g., flash point, autoignition temperature).
    — environmental properties (e.g., biodegradability, aquatic toxicity, odor threshold).
  3. What unwanted hazardous reactions or decompositions can develop:
    — because of improper storage?
    — because of impact or shock?
    — because of foreign materials?
    — because of abnormal process conditions (e.g., temperature, pH)?
    — because of abnormal flow rates?
    — because of missing ingredients or misproportioned reactants or catalysts?
    — because of mechanical failure (e.g., pump trip, agitator trip) or improper operation (e.g., started early, late, or out of sequence)?
    — because of sudden or gradual blockage or buildup in equipment?
    — because of overheating residual material (i.e., heels) in equipment?
    — because of a utility failure (e.g., inert gas)?
  4. What data are available or should be obtained on the amount and rate of heat and gas evolution during reaction or decomposition of any materials?
  5. What provisions are made for preventing runaway reactions and for quenching, shortstopping, dumping, or venting an existing runaway?

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  1. What is the potential for external fire (which may create hazardous internal process conditions)?
  2. How much experience do the facility and company have with the process? If limited, is there substantial industry experience? Is the company a member of industry groups that share experience with particular chemicals or processes?
  3. Is the unit critical to overall facility operations on a throughput or value-added basis?
  4. Does shutdown of this unit require other units to be shut down as well?

B. Unit Siting and Layout

  1. Can the unit be located to minimize the need for off-site or intra-site transportation of hazardous materials?
  2. What hazards does this unit pose to the public or to workers in the control room, adjacent units, or nearby office or shop areas from:
    — toxic, corrosive, or flammable sprays, fumes, mists, or vapors?
    — thermal radiation from fires (including flares)?
    — overpressure from explosions?
    — contamination from spills or runoff?
    — noise?
    — contamination of utilities (e.g., potable water, breathing air, sewers)?
    — transport of hazardous materials from other sites?
  3. What hazards do adjacent facilities (e.g., units, highways, railroads, undergroundaterials pipelines) pose to personnel or equipment in the unit from:
    — toxic, corrosive, or flammable sprays, fumes, mists, or vapors?
    — overpressure from explosions?
    — thermal radiation from fires (including flares)?
    — contamination?
    — noise?
    — contamination of utilities (e.g., potable water, breathing air, sewers)?
    — impacts (e.g., airplane crashes, derailments, turbine blade fragments)?
    — flooding (e.g., ruptured storage tank, plugged sewer)?
  4. What external forces could affect the site? Consider:
    — high winds (e.g., hurricanes, typhoons, tornadoes).
    — earth movement (e.g., earthquakes, landslides, sink holes, settling, freeze/thaw heaving, coastal/levee erosion).
    — snow/ice (e.g., heavy accumulation, falling icicles, avalanches, hail, ice glaze).
    — utility failures from outside sources.
    — releases from adjacent plants.
    — sabotage/terrorism/war.
    — airborne particulates (e.g., pollen, seeds, volcanic dust, dust storm).
    — natural fires (e.g., forest fires, grass fires, volcanism).
    — extreme temperatures (causing, for example, brittle fracture of steel).
    — flooding (e.g., hurricane surge, seiche, broken dam or levee, high waves, intense precipitation, spring thaw).
    — lightning.
    — drought (causing, for example, low water levels or poor grounding).
    — meteorite.
    — fog.

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  1. Is there adequate access for emergency vehicles? Could access roads be blocked by trains, highway congestion, etc.?
  2. Are access roads well engineered to avoid sharp curves? Are traffic signs provided?
  3. Is vehicular traffic appropriately restricted from areas where pedestrians could be injured or equipment damaged?
  4. Are vehicle barriers installed to prevent impact to critical equipment adjacent to high traffic areas?

II. Equipment

A. Pressure and Vacuum Relief

  1. Can equipment be designed to withstand the maximum credible overpressure generated by a process upset?
  2. Where are emergency relief devices needed (e.g., breather vents, relief valves, rupture disks, and liquid seals)? What is the basis for sizing these (e.g., utility failure, external fire, mispositioned valve, runaway reaction, thermal expansion, tube rupture)?
  3. Is the relief system designed for two-phase flow? Should it be?
  4. Is any equipment that is not protected by relief devices operating under pressure or capable of being overpressurized by a process malfunction?
  5. Where are rupture disks installed in series with relief valves?
    — Is there a pressure indicator (e.g., gauge, transmitter, switch) and vent between the rupture disk and relief valve?
    — How often is the pressure indicator read? Should an automatic bleeder be installed with an excess flow check valve and pressure alarm?
    — Were the relief devices sized considering the pressure drop through the entire assembly?

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  1. Are the flare, blowdown, and off-gas systems adequately purged, sealed or otherwise protected against air intrusion? Are there suitable flame arrestors installed in the piping?
  2. Will the relief devices withstand the damaging properties (e.g., corrosion, autorefrigeration, embrittlement) of the relieved material, as well as other materials that may be present in the relief header? Is the material likely to plug the internals of the relief device (e.g., balanced bellows)?
  3. What provisions are there for removing, inspecting, testing, and replacing vents, vacuum breakers, relief valves, and rupture disks? Who is responsible for scheduling this work and verifying its completion?
  4. What is the plant policy regarding operation with one or more disabled relief devices (e.g., inoperative or removed for testing or repair)? Is the policy followed?
  5. Are the flare, blowdown, and off-gas systems capable of handling overpressure events (including loss of utilities) for the plant as it currently exists (e.g., after plant expansions and debottlenecking)? What are the worst case scenarios for the process discharging into these systems?
  6. Are there separate cold and wet relief systems? Are relief valve discharges directed to the proper system?

B. Piping and Valves

  1. Is the piping specification suitable for the process conditions, considering:
    — compatibility with process materials and contaminants (e.g., corrosion and erosion resistance)?
    — compatibility with cleaning materials and methods (e.g., etching, steaming, pigging)?
    — normal pressure and temperature?
    — excess pressure (e.g., thermal expansion or vaporization of trapped liquids, blocked pump discharge, pressure regulator failure)?
    — high temperature (e.g., upstream cooler bypassed)?
    — low temperature (e.g., winter weather, cryogenic service)?
    — cyclical conditions (e.g., vibration, temperature, pressure)?
    — Is the piping particularly vulnerable to external corrosion because of its design (e.g., material of construction, insulation on cold piping), location (e.g., submerged in a sump), or environment (e.g., saltwater spray)?
  2. Is there any special consideration, for either normal or abnormal conditions, that could promote piping failure? For example:
    — Would flashing liquids autorefrigerate the piping below its design temperature?
    — Could accumulated water freeze in low points or in dead-end or intermittent service lines?
    — Could cryogenic liquid carry-over chill the piping below its design temperature?
    — Could heat tracing promote an exothermic reaction in the piping, cause solids to build up in the piping, or promote localized corrosion in the piping?
    — Could the pipe lining be collapsed by vacuum conditions?
    — Could a process upset cause corrosive material carry-over in the piping, or could dense corrosive materials (e.g., sulfuric acid) accumulate in valve seats, drain nipples, etc.?
    — In high temperature reducing service (e.g., hydrogen, methane, or carbon monoxide), could metal dusting cause catastrophic failure? Is the piping protected by suitable chemical addition (e.g., sulfides)?
    — Is the piping vulnerable to stress corrosion cracking (e.g., caustic in carbon steel piping, chlorides in stainless steel piping)? Should the piping be stress relieved?
    — Is the piping vulnerable to erosion? Are piping elbows and tees designed to minimize metal loss, and are they periodically inspected?
    — Could rapid valve closure or two-phase flow cause hydraulic hammer in the piping?
    — Should valve opening/closing rates be dampened to avoid piping damage?
    — Are there flexible connections that could distort or crack?
  3. Can piping sizes or lengths be reduced to minimize hazardous material inventories?
  4. Have relief devices been installed in piping runs where thermal expansion of trapped fluids (e.g., chlorine) would separate flanges or damage gaskets?
  5. Are piping systems provided with freeze protection, particularly cold water lines, instrument connections, and lines in dead-end service such as piping at standby pumps? Can the piping system be completely drained?

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  1. Will control valve malfunction result in exceeding the design limits of equipment or piping?
    — Are upstream vessels between a pressure source and the control valve designed for the maximum pressure when the control valve closes?
    — Some piping’s class decreases after the control valve. Is this piping suitable if the control valve is open and the downstream block closed? Is other equipment in the same circuit?
    — Is there any equipment whose material selection makes it subject to rapid deterioration or failure if any specific misoperation or failure of the control valve occurs (overheating, overcooling, rapid corrosion, etc.)?
    — Will the reactor temperature run away?
    — Is the three-way valve used in a pressure-relieving path the equivalent of a fully openport in all valve positions?
  2. Is there provision in the design for a single control valve to fail:
    — in the worst possible position (usually opposite the fail-safe position)?
    — with the bypass valve open?
  3. Upon a plant-wide or unit-wide loss of control medium or signal, which valves should fail to a position that is different from their normal failure positions? How were the conflicts resolved?
  4. Can the safety function of each automatically controlled valve be tested while the unit is operating? Will an alarm sound if the sensing-signal-control loop fails or is deactivated? Should any bypass valves be car-sealed or locked closed?
  5. Are battery limit block valves easily accessible in an emergency?
  6. Are controllers and control valves readily accessible for maintenance?

C. Pumps

  1. Can the pump discharge pressure exceed the design pressure of the casing?
    — Does the pump casing design pressure exceed the maximum suction pressure plus the pump shutoff pressure?
    — Is there a discharge-to-suction relief valve or minimum flow valve protecting the pump (set below the casing design pressure minus the maximum suction pressure)?
    — How would a higher density fluid affect the discharge pressure (e.g., during an upset, start-up, or shutdown)?
    — How would pump overspeed affect the discharge pressure?
    — Do any safety signals that close a pump’s minimum flow bypass also shut down the pump?
  2. Can the pump discharge pressure exceed the design pressure of downstream piping or equipment?
    — If a downstream blockage could raise the pump suction pressure, is the downstream piping and equipment rated for the maximum suction pressure plus the pump shutoff pressure?
    — If a downstream blockage would not raise pump suction pressure, is the downstream piping and equipment rated for the greater of (1) normal suction pressure plus the pump shutoff pressure or (2) maximum suction pressure plus normal pump differential pressure?

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  1. Can the pump suction be isolated from the feed source in an emergency?
    — Considering the materials, process conditions, and location, can operators safely close the isolation valve(s) during a fire or toxic release?
    — Are remotely operable valves, valve actuators, power cables, and instrument cables fireproofed?
  2. Would leakage of the process fluid into the motor of a canned pump be hazardous?

D. Compressors

  1. Can the compressor discharge pressure exceed the design pressure of the casing?
    — Does the compressor casing design pressure exceed the maximum suction pressure plus the compressor shutoff pressure? Is this true for each stage?
    — Is there a discharge-to-suction relief valve or recycle valve protecting the compressor (set below the casing design pressure minus the maximum suction pressure)?
    — How would a higher density fluid (e.g., during an upset, start-up, or shutdown) affect the discharge pressure?
    — How would compressor overspeed affect the discharge pressure?
    — Is there a relief valve for each low pressure stage capable of discharging the maximum recycle flow?
    — Do any safety signals that close a compressor’s recycle valve also shut down the compressor?
  2. Can the compressor discharge pressure exceed the design pressure of downstream piping or equipment?
    — If a downstream blockage could raise the compressor suction pressure, is the downstream piping and equipment rated for the maximum suction pressure plus the compressor shutoff pressure?
    — If a downstream blockage would not raise compressor suction pressure, is the downstream piping and equipment rated for the greater of (1) normal suction pressure plus the compressor shutoff pressure or (2) maximum suction pressure plus normal compressor differential pressure?
    — Are pulsation dampeners provided to protect against metal fatigue?

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  1. Are air compressor intakes protected against contaminants (rain, birds, flammable gases, etc.)?
  2. If the compressor is in an enclosed building, are proper gas detection and ventilation safeguards installed?

E. Reactors

  1. What would cause an exothermic reaction in the reactor?
    — Would quench failure or loss of external cooling cause a runaway reaction?
    — Would an excess (e.g., a double charge) or deficiency of one reactant cause a runaway reaction?
    — Would contaminants (e.g., rust, air, water, oil, cleaning agents, metals, other process materials) cause a runaway reaction?
    — Would inadequate cleaning cause a runaway reaction?
    — Would reactants added in the wrong order cause a runaway reaction?
    — Can loss of agitation in a cooled, stirred reactor lead to excessive temperature/pressure and a subsequent runaway reaction?
    — Could loss of agitation in a heated, jacketed reactor lead to localized overheating at liquid surface and a subsequent runaway reaction?
    — Could local hot spots result from partial bed obstruction?
    — Will excessive point or surface temperature lead to thermal decomposition or a runaway reaction?
    — Would delayed initiation of batch reaction during reactant addition cause a runaway reaction?
    — Could an exothermic reaction be caused by leakage of heat transfer fluid from the
    jacket or internal coil into the reactor?
    — Could backflow of material through a drain, vent, or relief system lead to or exacerbate a runaway reaction?
    — Will excessive preheating drive the reaction further?
    — Would a loss of purge or inerting gas cause a runaway reaction?
  2. What would be the effect of an agitator
    — failing?
    — failing and later restarting?
    — being started late?
    — running too fast or too slow?
    — running in the reverse direction?

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  1. What hazards are associated with the reactor catalyst?
    — Is the catalyst pyrophoric either before or after use?
    — Could the catalyst attack the reactor (or downstream equipment) during normal use, during an abnormal reaction, or during regeneration?
    — Is the fresh or spent catalyst toxic? Will it emit toxic gases when dumped from the reactor?
  2. What hazards are associated with regenerating the catalyst or bed?
    — Is a runaway reaction possible?
    — Are regeneration feeds (e.g., air) adequately isolated during normal operation?
    — Are there interlocks to prevent simultaneous operation and regeneration?
    — How are accidental flows prevented in multiple reactor systems where one reactor is regenerated while others remain in operation?

F. Vessels (Tanks, Drums, Towers, etc.)

  1. Are all vessels regularly inspected (e.g., x-ray, ultrasound) and pressure tested? Would the inspection method reliably detect localized damage (e.g., hydrogen blistering, fretting)? Do all pressure vessels conform to state and local requirements? Are they registered? Has the history of all vessels been completely reviewed? When were they last inspected?
  2. Is the pressure relief for the vessel adequate?
    — What is the design basis for the relief system (e.g., cooling water failure, external fire, blocked flow, blowdown from upstream vessel)?
    — Is a thermal expansion relief valve needed for small, liquid-filled vessels that would not otherwise require a relief valve?
    — Is a vacuum relief system needed to protect the vessel during cooldown or liquid withdrawal?
    — What would happen if a slug of water were fed to the vessel?

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  1. What vessel levels are vital for the operation of process units (e.g., levels required for pump suction pressure or surge capacity between or after process equipment)? How are these levels monitored?
  2. Are the contents of all storage vessels identified?

G. Heat Exchangers

  1. What are the consequences of a tube failure in a heat exchanger (or a heating/cooling coil failure in a vessel)?
    — Will the fluids react, leading to high pressure, high temperature, or formation of solids?
    — Will the fluid flash and autorefrigerate the system, possibly freezing the other fluid or embrittling the exchanger material?
    — Will the leaking fluid cause toxic or flammable emissions in an unprotected area
    (e.g., at the cooling tower)?
    — Will the leaking fluid cause corrosion, embrittlement, or other damage to equipment
    (including gaskets and seals) in the low pressure circuit?
  2. Is the pressure relief for both sides of the heat exchanger adequate?
    — Can the exchanger withstand exposure to the maximum pressure source upstream or downstream?
    — What if a tube ruptures (particularly if the high-pressure side’s design rating is more than 150% of the low-pressure side’s rating, or if the differential pressure in a double pipe exchanger is 1000 psi or more)?
    — What if the exchanger were exposed to an external fire?
    — What if the cold fluid expands/vaporizes because it is blocked in?
    — What is the pressure drop between the exchanger and the relief device protecting it?
    — Can hot fluid (e.g., steam) condense and create a vacuum if the exchanger is blocked in?
    — What if the fluid freezes in the exchanger?

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  1. How reliable is the cooling water supply?
    — Are motor-driven and turbine-driven pumps used?
    — Are there multiple sources of makeup water?
    — Is there any spare capacity in the cooling towers?
    — Are autostart systems regularly tested?
  2. Are there adequate equipment clearances so that maintenance can be performed safely (e.g., cleaning or removal of a tube bundle)?

H. Furnaces and Boilers

  1. Is the firebox protected against explosions?
    — Does the burner control system meet all applicable codes and standards (e.g., NFPA)?
    — How is the firebox purged before start-up? If steam is used, are the valves located away from the firebox? Is there a purge timer?
    — Are dedicated, positive shutoff trip valves installed in every fuel line? Must these valves be manually reset? Are bypass valves locked closed?
    — What signals will trip the furnace: low fuel pressure? high fuel pressure? loss of pilot or main flame? high stack temperature? low combustion air flow? low atomizing air/steam flow? loss of instrument air or power? low flow of water or process material?
    — How often are the furnace trips tested?
    — Are the fuel pressure sensors downstream of the fuel control valves?
    — Will air or stack dampers fail in a safe condition?
    — Can the forced draft fan overpressurize the firebox?
    — If several fireboxes share a common stack, will fuel leaking into one firebox be ignited by exhaust from the other fireboxes?
    — Could a tube failure cause an explosion?
    — Are there explosion hatches in the firebox?
    — Can flammable or combustible gases enter the firebox via the combustion air supply system?

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  1. Is the furnace adequately protected against tube failures?
    — Are individual pass flow controls, indications, and alarms provided?
    — Will a loss of process flow or drum level trip the furnace (but not the pilots)?
    — Are there check valves or remotely operable isolation valves in the outlet of each coil to prevent backflow in the event of a tube rupture?
    — Are there remotely operable valves (with appropriate fireproofing) in the furnace inlet lines, or are manual isolation valves located where they could be closed in the event of a fire?
    — Are relief valves provided for each coil with suitable protection against plugging (e.g., coking) the valves’ inlets?
    — How would flame impingement on a tube be detected before it led to tube failure?
    — Is snuffing steam supplied to the firebox? Are the valves located where they could be opened in the event of a fire? Are there adequate traps and drains in the snuffing steam lines?

I. Instrumentation

  1. Have instruments critical to process safety been identified and listed with an explanation of their safety function and alarm setpoints?
  2. Has the process safety function of instrumentation been considered integrally with the process control function throughout plant design?
  3. What has been done to minimize response time lag in instruments directly or indirectly significant to process safety? Is every significant instrument or control device backed up by an independent instrument or control that operates in an entirely different manner? In critical processes, are these first two methods of control backed up by a third, ultimate safety shutdown?
  4. What would be the effect of a faulty sensor transmitter, indicator, alarm, or recorder? How would the failure be detected?

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  1. Are instrument sensing lines adequately purged or heat traced to avoid plugging?
  2. What are the effects of atmospheric humidity and temperature extremes on instrumentation? What are the effects of process emissions? Are there any sources of water (e.g., water lines, sewer lines, sprinklers, roof drains) that could drip into or spray onto sensitive control room equipment?
  3. Is the system completely free of instruments containing fluids that would react with process materials?
  4. What is being done to verify that instrument packages are properly installed, grounded, and designed for the environment and area electrical classification? Is instrument grounding coordinated with cathodic protection for pipes, tanks, and structures?
  5. Are the instruments and controls provided on vendor-supplied equipment packages compatible and consistent with existing systems and operator experience? How are these instruments and controls integrated into the overall system?

J. Electrical Power

  1. What is the area electrical classification?
    — What process characteristics affect the classification, group, and division?
    — Are the hardware (e.g., motors, forklifts, vent fans, radios) and protective techniques consistent with the area electrical classification?
    — Was all equipment tested and approved by an independent laboratory (e.g., Underwriters Laboratories or Factory Mutual), or is additional testing required?
    — Are any new protective techniques being employed?
  2. Is all auxiliary electrical gear (e.g., transformers, breakers) located in safe areas (e.g., from hazardous materials and flooding)?
  3. Are electrical interlocks and shutdown devices made fail-safe?
    — What is the purpose of each interlock and shutdown?
    — Can the interlock and shutdown logic be simplified?
    — How is continued use of protective devices ensured?
    — How often are the interlocks and shutdowns tested under load?

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  1. Are trucks and railcars properly grounded during loading/unloading operations?
  2. What electrical equipment can be taken out of service for preventive maintenance without interrupting production? Can the equipment be safely locked out? How?
  3. Are conduits sealed against flammable vapors?

K. Miscellaneous

  1. Are special seals, packing, or other closures necessary for severe service conditions (e.g., toxic, corrosive, high/low temperature, high pressure, vacuum)?
  2. Do major pieces of rotating equipment have adequate equipment integrity shutdowns to minimize major damage and long-term outages (e.g., lube oil shutdowns)?
  3. Is the equipment’s vibration signature routinely monitored to detect incipient failures? How is excessive vibration detected? Will excessive vibration trip large rotating equipment such as
    — turbines?
    — pumps?
    — motors?
    — cooling tower fans?
    — compressors?
    — blowers?
  4. What is the separation of critical and operating speeds? Will the equipment trip on overspeed? Could overspeed or imbalance cause the equipment to disintegrate?

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  1. What could cause a catastrophic failure of the piping or equipment (e.g., hydrogen cracking, thermal shock, external impact)?
  2. Are there suitable barricades between process equipment and adjacent roadways? Are overhead pipe racks protected from crane impacts?
  3. Does all equipment comply with applicable laws and regulations, codes and standards, and company guidelines?
  4. What tests will be performed to detect specification errors, manufacturing defects, transportation damage, construction damage, or improper installation before the equipment is put into service? What ongoing tests, inspections, and maintenance are performed to ensure long-term reliability and integrity of the equipment?

III. Operations

  1. What human errors may have catastrophic consequences? Have critical jobs and tasks been identified? Have the mental and physical aspects of such jobs been analyzed for both routine and emergency activities? What has been done to reduce the likelihood and/or consequences of potential human errors in the performance of these jobs?
  2. Is a complete, current set of procedures for normal operations, start-ups, shutdowns, upsets, and emergencies available for operators to use? How are specific, up-to-date procedures maintained? Do the operators themselves help review and revise the procedures? How often? Are known errors allowed to remain uncorrected?
  3. What process equipment or parameters have been changed? Have the operating procedures been appropriately revised and have operators been trained in the new procedures?
  4. Are procedures written so workers can understand them, considering their education, background, experience, native language, etc.? Is a step-by-step format used? Are diagrams, photographs, drawings, etc., used to clarify the written text? Are cautions and warnings clearly stated in prominent locations? Does procedure nomenclature match equipment labels? Are there too many abbreviations and references to other procedures?

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  1. Should television cameras be installed
    — to watch loading/unloading racks?
    — to watch flare tips?
    — to watch for process material releases?
    — to watch for intruders?
  2. What loading and unloading operations are performed?
    — What procedures control these operations?
    — Who performs these operations?
    — How is training/familiarization conducted for company and noncompany personnel involved in these operations?
    — How is surveillance or supervision maintained?
    — How are hookups performed? Are there any physical means to prevent reversed
    connections or connections to the wrong tank?
    — How is the transport container grounded/bonded? Is the electrical continuity verified?
    — How is the raw material or product composition verified?
    — Is the composition verified before any material transfer takes place?
  3. Are adequate communications provided to operate the facility safely (telephones, radios, signals, alarms)?
  4. Are shift rotation schedules set to minimize the disruption of workers’ circadian rhythms? How are problems with worker fatigue resolved? What is the maximum allowable overtime for a worker, and is the limit enforced? Is there a plan for rotating workers during extended emergencies?
  5. Are there enough operators on each shift to perform the required routine and emergency tasks?

IV. Maintenance

  1. Are written procedures available and followed for:
    — hot work?
    — hot taps and stopples (including metal inspection before welding)?
    — opening process lines?
    — confined space or vessel entry?
    — work in an inert atmosphere?
    — lockout/tagout?
    — work on energized electrical equipment?
    — blinding before maintenance or vessel entry?
    — pressure testing with compressible gases?
    — use of supplied-air respiratory equipment?
    — removal of relief devices from operating equipment?
    — digging and power excavation?
    — cranes and heavy lifts?
    — contractor work?
    — entry into operating units?
  2. What procedures govern crane/heavy equipment usage in an operating unit?
    — Is operator certification required?
    — Are equipment/cable inspections and certifications current?
    — How are underground voids or piping positioned before a heavy lift is performed?
  3. Is it necessary to shut down the process completely to safely repair a piece of equipment? Are there provisions for blanking off all lines into equipment that people may enter? Are other precautions necessary to protect operators, mechanics, and service personnel?

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  1. Are the right tools available and used when needed? Are special tools required to perform any tasks safely or efficiently? What steps are taken to identify and provide special tools?
  2. What kind of special housekeeping is required? Will accumulation of small spills cause slippery floors, or powder accumulation possibly cause a dust explosion?
  3. What hazards do adjacent units pose to maintenance workers? Consider:
    — normal exhausts and vents.
    — emergency relief and blowdown.
    — accidental releases and spills.
    — fires and explosions.

V. Personnel Safety

A. Building and Structures

  1. What standards are being followed in the design of stairways, platforms, ramps, and fixed ladders? Are they well lit?

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  1. Does the control room provide a safe haven during accidents, protecting operators from potential fires, explosions, and toxic releases? What is the design basis for the protection? What are the evacuation plans? If a shelter-in-place strategy is used, are there enough SCBAs for control room personnel and others who may come there in an emergency?

B. Operating Areas

  1. What fire and explosion hazards are workers exposed to, and how are the hazards mitigated? Are there:
    — flammable conditions in process equipment?
    — combustible materials near hot process equipment?
    — spills/releases of flammables or combustibles?
    — accumulation of flammables or combustibles (e.g., dusts, oily sumps)?
    — cleaning solvents?
    — strong oxidizers (e.g., peroxides, oxygen gas)?
    — ignition sources (e.g., open flames, welding, resistance heaters, static)?
  2. How is high pressure vented from the area?
  3. Has a safe storage and dispensing location for flammable liquid drums been provided?
  4. What chemical hazards are workers exposed to, and how are they mitigated? (Consider raw materials, intermediates, products, by-products, wastes, accidental reactions, and combustion off-gases.) Are there:
    — asphyxiants?
    — carcinogens?
    — irritants?
    — mutagens?
    — poisons?
    — teratogens?
  5. Where may workers be exposed to chemical hazards? Are special protective measures (e.g., special ventilation) required? Consider:
    — collecting samples?
    — gauging tanks, vessels, or reservoirs?
    — charging raw materials?
    — withdrawing or packaging products?
    — loading/unloading trucks, railcars, or drums?
    — cleaning filters or strainers?
    — purging/draining process chemicals from lines and vessels?
    — draining/venting wastes?

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  1. What electrical hazards are workers exposed to, and how are these hazards mitigated? Do they include:
    — shock?
    — burn?
    — arcing/electrical explosion?
    — unexpected energization?
  2. Are positive disconnects and interlocks being installed for lockout of all energy sources?
  3. What radiation hazards are workers exposed to, and how are they mitigated? Do they include:
    — ionizing radiation?
    — ultraviolet light?
    — high intensity visible light?
    — infrared radiation?
    — microwave radiation?
    — laser beams?
    — intense magnetic fields?
  4. Are there at least two exits from hazardous work areas?
  5. How good is the lighting system?
    — Adequate for safe normal operation?
    — Adequate for routine maintenance?
    — Adequate for shutdown during a power failure?
    — Adequate for escape lighting during a fire?

C. Yard

  1. Are material loading/unloading operations continuously monitored by an operator (in the yard or via closed circuit television)?
  2. Is yard lighting adequate?

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  1. Is safe access provided for employees who work atop storage tanks?
  2. re railroad car puller control stations fully protected against broken cable whiplash? What will protect the operator fArom being caught between a cable or rope and the capstan or cable drum?

VI. Fire Protection

  1. What combustible mixtures can occur within equipment:
    — because of normal process conditions?
    — because of abnormal process conditions?
    — because of a loss or contamination of gas for purging, blanketing, or inerting?
    — because of moving liquids into and out of vessels (e.g., tank breathing)?
    — because of dust?
    — because of improper start-up, shutdown, or restoration after maintenance?
    — because dissolved or chemically bound oxygen was released and accumulated?
    — because of condensation in the ducts?
  2. What is the approximate inventory of flammable liquids in the equipment? Are inventory amounts kept to a minimum?
  3. How have major storage tanks or vessels been located to minimize the hazard to process equipment if the tanks catch fire or rupture? Are liquid-filled tanks near the ground?
  4. What combustible materials are present? How are they protected from fire, sparks, and excessive heat?
  5. Are fire walls, partitions, or barricades provided to separate high-value property, highhazard operations, and units important for production continuity? Do fire doors have fusible link closures?

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  1. Are critical isolation valves fire-safe, and will their actuators withstand fire exposure?
  2. Has adequate drainage been provided to carry spilled flammable liquids and water used for fire fighting away from buildings, storage tanks, and process equipment? Are drain valves outside any dikes? Can the drains and dikes accommodate the water used during fire fighting? Will burning materials float into adjacent areas?
  3. Is the control room adequately protected against external fires or explosions? Do any glass windows face process areas where explosions might occur?
  4. Are fire protection systems periodically tested? Is there a program to ensure that fire protection systems are in service? Does the program provide priority maintenance for equipment found out of service?
  5. Are there strong administrative controls requiring permits and/or notification before fire protection equipment can be taken out of service or used for normal operation (e.g., auxiliary cooling) or maintenance (e.g., equipment flushing)?

VII. Environmental Protection

  1. Are there any chemicals handled that are particularly sensitive from an environmental standpoint? (carcinogens, volatile toxics, odorants)
  2. Have all effluent streams been defined? Are they hazardous? What is their disposition? Are scrubbers required? Have permit requirements been addressed? What has been done to minimize effluents and wastes? Will any hazardous materials such as heavy metals reach the waste treatment plant?
  3. Does surface water runoff require any special treatment? Is surface drainage adequate? Can it be protected (e.g., with sandbags) from process material spills?
  4. How are effluents monitored (e.g., sampled) for unacceptable emissions? What is the lag time between measurement and alarm or notification? Do emission points include:
    — stacks and vents?
    — ventilation exhausts?
    — surface water runoff?
    — discharges to city sewers?
    — discharges to surface water bodies?
    — discharges or seepage to groundwater?
  5. What precautions are necessary to meet environmental requirements and protect human health? Are there specific environmental restrictions that will limit operations?

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  1. Are there any suppression, absorption, or cleaning media that are prohibited (because they are not effective, they react with some other chemical present in the area, or they are harmful to equipment)? Are any media of this type available in the area? If water is prohibited, are there warning signs in the area?
  2. What are the capabilities of the spill response team?
    — How is the spill response team assembled during the day shift? off-shifts?
    — What procedures do emergency personnel follow when entering a unit?
    — What protective equipment is available to the emergency personnel? Are enough SCBAs available? Will protective gear withstand exposure to process chemicals?
    — What release suppression, collection, and cleanup equipment is available in the facility? from mutual aid groups? from the community?
  3. Can wastes be safely handled? Can the material be decontaminated, recycled, or destroyed? Have arrangements for disposal been completed?
  4. What means is provided for disposal of off-specification products or aborted batches?
  5. Are empty containers for packaged raw materials and intermediates systematically recycled or disposed of by acceptable methods?

VIII. Management and Policy Issues

  1. Is upper management’s commitment to employee health and safety clear? What policy statements communicate this commitment to employees? Do workers understand these policies, and are they convinced of upper management’s sincerity?
  2. Do supervisors and workers believe that safety has higher (or at least equal) status with other business objectives in the organization? How does the company promote a “safety first” approach?
  3. Have supervisors and workers been specifically told to err on the safe side whenever they perceive a conflict between safety and production? Will such decisions be supported throughout the management chain?
  4. Is there a policy that clearly establishes which individuals have the authority to stop work if safety requirements are not met?
  5. Is management of worker health and safety an essential part of a manager’s daily activities? How are managers held accountable for their health and safety record, and how do the rewards and penalties compare to those for production performance?

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  1. Are engineering drawings or models up to date, including those related to environmental management permits?
  2. What administrative control is necessary to ensure replacement of proper materials during construction/modification/maintenance to avoid excessive corrosion and to avoid producing hazardous compounds and reactants?
  3. What is the company policy toward compliance with process safety guidelines published by industry or trade groups such as the Chemical Manufacturers Association, the American Petroleum Institute, or the Chlorine Institute? Have they been followed in this design?
  4. Is there an audit program that regularly reviews safety compliance? Do workers participate on the audit teams? Who sees and responds to audit reports?
  5. Are there programs for identifying and helping workers with substance abuse or mental health problems? What counseling, support, and professional advice is available to workers during periods of ill health or stress? What is the company policy on reassigning or terminating workers who are unable/unfit to perform their jobs?

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