Introduction to Hazardous Evaluation Techniques

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Introduction to Hazardous Evaluation Techniques

• Guidelines for Hazardous Evaluation Procedures
  (1992 by AIChE).
• Second Edition with Worked Examples.
• Center for Chemical Process Safety (CCPS).
• American Institute of Chemical Engineers (AIChE).

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Hazard Evaluation Techniques
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HAZOP

• HAZOP was developed by Lawley (1974) of ICI.
  Based on early account by Elliott Owen (1968).
• Hazop studies are carried out by an experienced,
  multidisciplanary team.
• Review all physical aspects of a process (lines,
  equipment, instrumentation) to discover potential
  hazards.

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Basis for HAZOP

• The basis for a HAZOP is a critical examination
  of information found in a word model.
• It includes a flowsheet, a plant layout,
  equipment specification or a PID, (Piping and
  Instrument Drawing).

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Hazop Includes
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Hazop Guide Words
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Common HAZOP Analysis Process Parameters
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Prepare for the Review
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HazopFlowSheet
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Hazop Pitfalls
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Other Pitfalls

• Inexperienced HAZOP team.
• Inadequately trained or in-experienced leader.

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Common Hazop Mistakes

• Failing to establish a "safe" environment for
  team members.
• Consequences of events not carried to conclusion.
• Taking unwarranted credit for safeguards.
• Too little credit given for safeguards.

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Hazop Mistakes Contd

• Failure to make recommendations as specific as
  possible.
• Poor record keeping of HAZOPS.
• Failure to HAZOP start-up and shut-down
  procedures.
• PIDs not up-dated or poorly constructed.

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Hazop Mistakes Contd

• A HAZOP is performed in lieu of properly executed
  design reviews.
• Wrong technique for system being reviewed (See
  spreadsheet titled Fig 5.3).

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HAZOP Example
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Standard Set of Deviations
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Typical Hazop Worksheet
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Check List Example
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Check List Contd
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Check List Contd
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End of HAZOP Presentation.

• Presented to ES-317y
• 27 Feb, 2001
• By R.A. Hawrelak