Safety Instrumented Systems (SIS)

OSHA has defined in its Letters of Interpretation that ISA 84 or IEC 61511 will define the necessary activities to mitigate adverse events in a processes unit.  Either standard defines the Layers of Protection Analysis (LOPA) that will determine consequences which need a safeguard or Independent Layers of Protection (IPL).  And when there are not enough IPLs to mitigate the risk, the standard requires a Safety Instrumented System (SIS) to mitigate or avoid adverse Safety and Health events.  The SIS consists of a calculated arrangement of software and hardware to manage safety critical processes to a “safe state.”

We are able to provide LOPA facilitators to assist with the analysis of your risk analysis to avoid unnecessary generation of mitigations. We are able to generate the Safety Requirement Sheet (SRS) with all the requirements of the safety instrumented functions necessary for SIS. Our experienced staff is able to determine if current systems meet SIS requirements or design the SIS to fill any gaps and verify IPLs from previous PHAs for compliance with industry standards.

  • Safety Integrity Level (SIL) Reviews
  • Develop Safety Requirement Sheet (SRS)
  • Verification of Independent Protection Layers (IPL)
  • Life Cycle Management