So you’re faced with the question of whether that trusty old transmitter you’ve been using as part of your safety shutdown system can meet the “prior use” requirements described in Section 11.5.3 of ANSI/ISA-84.00.01-2004 (IEC 61511-1 Mod).  Prior use, or Proven-in-use, is defined as a documented assessment showing ...

In attending last week’s 63rd Annual Texas A&M Instrumentation symposium, I was shocked to hear from a well respected safety expert that SFF (Safe failure fraction) was a failed metric.  No explanation, just that SFF was pretty much useless, followed by a cackle.  I really hate when people make profound statements like this, ...