Half a Century of Olefin Plant Accidents: The Role of Mechanical Integrity

Sebastian Diaz, Aon energy Risk Engineering, League City, TX.

Email: sebastian.diaz@aon.com

Russ Davis, CSP Aon Energy Risk Engineering, League City, TX.

Email: russ.davis@aon.com

Keywords: mechanical integrity, loss of containment, major accidents

Abstract

Since OSHA's Process Safety Management standard went into effect in 1992, the Mechanical Integrity element of the standard has been expected to be a key factor in reducing the occurrence of major chemical incidents.

Past statistics show that, in the refining industry, olefin units accidents/incidents account for close to one sixth of the total accidents, and close to one fifth of the total cumulative economic losses. We would expect, then, to see a significant reduction of these occurrences through the implementation of mechanical integrity programs, industry wide.

This work presents a brief examination of past records of several major incidents involving olefin plants from the last 50 years. The aim was to identify common causes and the impact of mechanical integrity on these causes. We found that approximately half of the incidents were caused by or involved mechanical integrity deficiencies, and even though the PSM standard has helped reduce the incidence, major losses due to MI deficiencies keep occurring.