I posted this question in a PSM group in LinkedIn:
"I am interested to know whether a comprehensive study has been done anywhere, after the introduction of LOPA in the late 90's, with the study objective - "Has LOPA actually led to a reduction in incidents?"
Thanks, in advance.."
William Bridges, one of the co inventors of the LOPA technique posted his comments as follows:
"I doubt seriously if such a study is possible as you have to hold ALL
OTHER influences constant and then start doing LOPA after that. I think
this would be useless graduate project as well (for the same reason).
As one of the co-inventors of LOPA, the greatest improvements I have
seen from the introduction of a LOPA, are from using the definition of
an IPL within PHA/HAZOPs and from maintaining all IPLs per their
respective industry best practices.
At a macro scale, it does not appear that introduction of LOPA or even
introduction of process safety best practices have reduced the number of
catastrophic accidents. This is no fault of the methods or disciplines;
this is because Most companies still choose to do the bare minimum.
Some companies have made great strides due to implementing best
practices in risk assessment and process safety management; the majority
have NOT improved because (1) their PHAs/HAZOPs still fail to find
scenarios during all modes of operation so they are missing IPLs they
need for those modes of operation, or (2) they fail to maintain IPLs
appropriately, or (3) they fail to implement effective steps against the
effectives of corrosion, erosion, or external impacts (for which there
are no IPLs)."
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