© SBM Offshore 2012. All rights reserved.
www.sbmoffshore.com25
SIF too slow
• Instrumentation solutions to speed up the SIS response time
• Allow the SIS Response time to be >50% of Process Safety Time
(ref [6] states
“Given the degree of uncertainty in the process safety time, the SIS should be capable of completing
its action within one-half of its allocated process safety time”)
• Go back to SIL assessment… is the hazard really credible?
Process Safety Time
SIS Response Time
Ref [6] ISA-TR84.00.004 part 1