Paul Gruhn and Dave Reynolds

Articles

Machine Safety March 1, 2006

Safety Integrity Level 3

Three safety integrity levels (SIL) were described in the ANSI/ISA-84.00.01-1996 standard. Revised standard ANSI/ISA 84.00.01-2004 (IEC 61511-1 mod) now includes the higher SIL 4. SILs are a measure of system performance: the higher the number, the better the safety performance, such as lower probability of failure on demand.

By Paul Gruhn and Dave Reynolds