Hazard%20and%20Operability%20Studies%20-%20HAZOP%20ChE%20258%20Chemical%20Process%20Safety%20University%20of%20Missouri%20-%20Rolla

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Hazard and Operability Studies - HAZOPChE
258Chemical Process SafetyUniversity of
Missouri - Rolla
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HAZOP

• Attributes
• Concepts
• Talk the Talk (Definitions)
• Example

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HAZOP

• An effective method to identify hazards
• Developed to identify hazards in a process plant
  and to identify operability problems, though not
  hazardous, that could compromise the plants
  ability to achieve design productivity

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HAZOPAttributes

• Purpose Identification of hazard and
  operability problems.
• When to use Optimal to be applied to new
  plants, but when design is nearly firm and
  documented. May be applied to existing
  plants where a major redesign is planned.
  Also on existing facilities

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HAZOPAttributes

• Type of Results Qualitative identification of
  hazards and operating problems.
  Recommended changes in design,
  procedures. Recommend for follow on studies.

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HAZOPAttributes

• Data Requirements HazOp requires detailed
  plant description, PFD (Process Flow Diagram),
  PID (Piping and Instrumentation Diagram),
  Plant Layout, Operating and Start
  up procedures.

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HAZOPAttributes

• Staff Requirements Five to seven members on
  team with support for recording and reporting.
  Mix of engineers, operators, maintenance,
  safety, etc.

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HAZOPAttributes

• Time and Cost Depends on complexity of plant
  being analyzed. In general 3 hours for each
  major hardware item. Additional time for
  planning, team coordination and documentation.

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HAZOPConcept

• Review plant by breaking it up into a series of
  nodes (major hardware or operation). The
  multidisciplinary team brainstorms the plant
  design or operating procedure.
• The idea is that several experts working together
  can achieve more, i.e., synergy.

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HAZOPTalk the Talk (Define terms)

• Study Nodes The location on PID or procedures
  at which the process parameters are investigated
  for deviation

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HAZOPTalk the Talk

• Intention How the process is expected to operate
  in the absence of deviations at the study nodes.

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HAZOPTalk the Talk

• Deviations Departures from the intention which
  are discovered by applying the guide words (e.g.
  more pressure).

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HAZOPGuide Words

• No Negation of design intent
• Less Quantitative decrease
• More Quantitative increase
• Part of Qualitative decrease
• As well as Qualitative increase
• Reverse Logical opposite of the intent
• Other than Complete substitution

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HAZOPGuide Words

• Sooner or Later Use for Other than when
  considering time
• Where else Use for Other than when considering
  position, sources, or destination
• Higher or Lower Use for More or Less when
  considering elevations, temperatures, or pressures

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HAZOPTalk the Talk

• Causes Identify the possible deviation. Search
  for credible cause for such a deviation. This is
  a meaningful deviation. Causes can be hardware,
  human error, external disruption, unanticipated
  process state, computer/power failure.

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HAZOPTalk the Talk

• Consequences These are the results of the
  deviations should they occur. Trivial
  consequences, relative to the study objective are
  dropped.

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HAZOPProcedure Summary
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HAZOPIn Class Assignment

• Work as a group with the Process flowsheet and
  PID diagram for the Williams-Otto process.
• Perform a guide work HAZOP for the appropriate
  process component and guide word as listed on the
  assignment sheet.
• Turn in your list of responses