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Use PFFM Instead of Hazop

  • Type:
    Conference Presentation
  • Conference Type:
    AIChE Spring Meeting and Global Congress on Process Safety
  • Presentation Date:
    April 3, 2012
  • Duration:
    30 minutes
  • Skill Level:
  • PDHs:

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While accepted world-wide as being the standard for process hazard analysis for many years, the HazOp review technique is cumbersome. This drives the team with limited time and/or resources to look for alternatives:
  • Short-cut the HazOp method in order to get the review done in a reasonable time. Not considering the operation of manual block valves as a cause is one example; assuming similar units have identical hazards and therefore don't need individual reviews is another.
  • Postpone the review until later, when more money may be available in the budget.
  • Postpone the review to a time when participants will have more time
  • Do not complete the review scope: either skip areas that appear to present lower risk, or stop when the scheduled time is used up and hope to reschedule a later meeting to complete the review.
  • Rush the review. One or more leaders urges the team to "work faster", and the team responds in order to get finished on time (typically, by being less thorough).
  • Use a What-if list instead of HazOp.
  • Use an in-house facilitator because it's cheaper and easier to schedule.

Rushing or shortcutting a HazOp review will likely result in missed hazards. These missed hazards can result in injury, loss of life, and/or asset damage to the facility. Postponing reviews or leaving portions of scope incomplete can delay identification of hazards. The facility is then sitting on a time bomb that may or may not go off before the review work is resumed/completed. In-house facilitators can be excellent if they are properly trained, have adequate background/experience, and are unbiassed; however, such people are more the exception than the rule. What-if reviews can lack structure and thoroughness, again resulting in missed hazards. Pareto analysis of hundreds of incidents in the U.S. over the past 20 years shows that failure to identify hazards has been a major contributing factor in a large proportion of those incidents.

If a company with limited resources is serious about preventing significant losses with its PSM program and any or all of the problems listed above sound familiar, it should switch immediately from HazOp to using Process Flow Failure Modes (PFFM), based on the LIST. The LIST is the backbone of the PFFM process hazards analysis technique and has been in use in Canada for over 15 years, with great success. Using the LIST makes process hazard analysis simpler, faster, more logical, and, in practice, identifies as many or more hazards than HazOp.

In this presentation, PFFM and the LIST will be introduced and one or more nodes for an example process facility will be pre-populated with causes to demonstrate the technique. One or two case studies comparing PFFM results with HazOp results will be covered. A method of incorporating PFFM into a more traditional HazOp structure will also be introduced. Open and lively discussion will be encouraged as the presentation progresses.

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