SIL Determination Methodology – Choosing the Best Method to Evaluate Your Process

The key to achieving Functional Safety for a process is development of a robust process for identifying required levels (Safety Integrity Levels, SIL) of risk reductions per IEC 61508 / 61511. 

After specific hazardous scenarios are identified and requirements for risk reduction are established, a SIL Determination method can be used to determine required SILs.  Multiple evaluation methods are available, the suitability of which is dependent upon several factors:

1. Scenario complexity,

2. Consequence severity,

3. Risk reduction required (the “gap” between estimated risk and target risk), and

4. Boundaries of the risk under consideration.