Verifying Safety Instrumented Functions Meet SIL Requirements

Recently the DeltaV News RSS feed announced a video case study for Australia’s Arrow Energy at their Tipton Gas plant.

I discovered that Bob Gale, an AIChE fellow and Sr. Technical/Safety Consultant in Emerson’s Refining and Chemical industry center was involved in this project. You may recall Bob from an earlier post about achieving IEC 61511 compliance.

Like more and more projects, a global team from Emerson was assembled to execute this project. Bob’s role was to do the safety integrity level (SIL) verifications for the project. Bob noted that a part of the IEC 61511 Safety Life Cycle for DeltaV SIS projects is to have an Emerson Certified SIS Consultant verify that the safety instrumented functions (SIF), as they were designed, meet the safety integrity level that is specified in the project.

Bob’s task was to ensure them that each SIF provided the risk reduction that was required to make things safe. One example he described was determining that this plant needed to divide one large SIF that encompassed the fire detection equipment on all the compressors into a single SIF for each compressor. This change allowed each of the smaller SIFs to provide the necessary risk reduction required. Each SIF is designed to shutdown the compressor in the event of a fire.

By working methodically through all of process equipment that required risk reduction, Bob played a key role for the project team in the plant’s IEC 61511 safety lifecycle efforts.

Posted Thursday, August 9th, 2007 under Project Services, Safety.

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