Process Safety What are the Odds? - Enhancing a safety system's ability to perform on demand requires improved diagnostic coverage, maintenance, and regular testing

摘要

Within process plants, layers of protection (LOP) include relief valves, rupture disks, dikes, and a safety-instrumented system (SIS). SISs are specially engineered solutions that are continuously online and expected to instantaneously take action to mitigate any detected unsafe process events. But with weeks, months, or even years between unsafe events, what can be done to minimize the probability of failure on demand (PFD) for some part of the SIS? The answer: select devices suitable for safety applications, engineer and install those devices using good engineering practices, apply sound maintenance practices, and test, test, test.