(43a) Best Practices in IPL Integrity Management - Case Study in Kuwait Oil Company

16^th Process Plant Safety Symposium (PPSS) – Validation and Maintenance of IPLs

This paper presents Management of Independent Protection Layers at Kuwait Oil Company (KOC), Kuwait.  Several methods and practices were initially followed by various project teams involved in SIL Assessment / Verification / Validation over several years since the SIL compliance was introduced.  However, little interaction existed across projects and Operation & Maintenance personnel.  As a result, valuable experience and observations from the actual plant operation were never fed back and were not integrated into the LOPA methodology.  The conditional modifiers remained un-changed for almost a decade.

In order to revalidate the IPLs, a task was carried out to systematically compile, analyze and prepare in easily understandable form, failure modes and effects over the past seven (7) years from five major process plants.  Mechanical, Electrical and Instrument failures were separately listed with their cause-consequence relations.  The consequences are rationalized against the Company’s LOPA criteria, in order to be able to sort them in the order of maximum to minimum consequence.  For the high consequence events, the initiating events that have caused them were compared with the cause-consequence pairs listed in the Company standard.  It was observed that for many of the high consequence events, the initiating events that were assumed were not the real ones as per the 7-year history.  A detailed report that followed presented this analysis to the stake-holders for further consideration, to be reflected in a revised Company standard and also to make this method of revalidation of IPLs a Company practice.   

An independent “Alarm Management” exercise issued a Company Alarm Management Philosophy document (APD).  After implementing the Alarm Management per the new APD, several of the existing Process alarms were either removed, or modified to give them lower priority.  The credits allowed by the LOPA standard now need revision to be in line with the APD.  This issue was highlighted and soon, the LOPA standard will be revised to reflect the same.

The Flare  & Blow-down systems in several of the company’s process plants were provided with SIL approved SDVs under one major project.  However, the credit for this SIF was not being reflected in most LOPA workshops.  This issue was highlighted and was subsequently corrected.

The access security for a few SIFs was agreed to be given to the senior process operators, thus increasing the risk profile, as against the original assumption that only the Operations Manager will be approving changes.  Hence these SIFs no longer deserve credits in LOPA and needed suitable modification in the LOPA standard.

The ‘type’ of equipment and thus their technology and reliability has changed significantly.  For example, the Tank Vapour compression was changed to electric motor driven centrifugal / screw type from previous gas-engine driven reciprocating type, thus decreasing vibrations in the tanks and piping systems.  Similar changes in other process units either decreased or increased the initiating events but these changes were not reflected in the frequencies and cause-consequence relationships of the initiating events.

All the above issues significantly impact the accuracy of the LOPA exercises and thus directly impact the Risk reduction in the process plants under consideration.  Sustained efforts over several years resulted in noticeable change in perceptions of Operation and Maintenance personnel and the 7-year failure data has significantly contributed to rationalizing the Company’s LOPA criteria to make it more meaningful for both existing and future process facilities.