Company: EnQuest

Project: Offshore SIL Verification Methodology


EnQuest required the development of a SIL verification procedure and Excel analytical tool, which enabled SIL classification of instrumented systems to be verified and demonstrated to the UK Health and Safety Executive.


PEAK reviewed all of EnQuest’s existing SIL and LOPA procedures, amending and aligning them accordingly. The team also ensured it reviewed the requirements of IEC EN 61508 and IEC EN 61511 in order to determine the basis of the verification tool.

The team then worked closely with various discipline engineers to develop several Excel spreadsheets. These culminated in the creation of a master spreadsheet that was used to verify each SIL loop achieved its designated integrity level.


This work has provided a smooth evaluation and verification for instrumented protective systems. This simplifies the whole process from HAZOP to SIL Assessment, LOPA and SIL Verification.