Safety Integrity Level (SIL) 

Industries rely heavily on functional safety to reduce risks to equipment that give rise to hazards.

Safety Integrity Level (SIL) studies are a key part of facility design which provide a measure of the risk reduction provided by a Safety Instrumented Function (SIF). This measurement has a direct effect on the safety design, operability, and investment costs of a facility. Therefore, when a facility implements a SIF to reduce an existing intolerable risk to a tolerable range, SIL is used.

For over 25 years SDS has performed and documented hundreds of SIL studies pursuant to the IEC 61508 standard. This standard defines four SILs, with SIL 4 being the most dependable assignment of safety and SIL 1 being the least. A Layers of Protection Analysis (LOPA) is typically used by SDS in the assignment of SIL and is by far the most common approach for any large facility.

 Assignment of SIL is an exercise in risk analysis where the level risk to be protected against by a SIF is calculated. SDS experts have effectively guided sessions which mitigate these risks to a tolerable level. Frequently SDS carries out a combined HAZOP and SIL session for its clients. Both are key elements in facility design.