Unavailability During Proof Tests: What Do You Do?

“…there’s a cat in a box somewhere who’s alive and dead at the same time (although if they don’t ever open the box to feed it, it’ll eventually just be two different kinds of dead)…”  — Neil Gaiman, in American Gods Erwin Schrödinger never intended his thought experiment about a cat in box to launch [...]

By |2022-06-30T15:48:00+00:00June 30th, 2022|Process Safety, Process Safety Management|Comments Off on Unavailability During Proof Tests: What Do You Do?

Yes, But…Hardware Fault Tolerance

“Therefore, by virtue of the authority vested in me by the Universita Committeeatum E Pluribus Unum, I hereby confer upon you the honorary degree of Th.D.,… er, ‘Doctor of Thinkology’.”  —The Wizard of Oz Most of our readers understand that for a Safety Instrumented Function—a SIF—to have a particular Safety Integrity Level—a SIL—its Average Probability [...]

By |2019-07-11T15:29:13+00:00July 11th, 2019|Procedures, Process Safety, Process Safety Management|Comments Off on Yes, But…Hardware Fault Tolerance

SIL Certification: Necessary or Sufficient?

“Contrary to what many parents tell their children, talent and hard work are neither necessary nor sufficient for economic success.”  —Robert H. Frank We are all guilty of telling tales we know to be untrue in order to encourage virtuous behavior. Parents tell their children to be good so Santa Clause will come. OSHA tells [...]

By |2019-05-23T16:10:03+00:00May 23rd, 2019|Process Safety|1 Comment

Wait For It! Are Trip Delays Okay?

“But the important thing about learning to wait, I feel sure, is to know what you are waiting for.”  —Anna Neagle Many safety instrumented functions (SIFs) are deliberately designed to wait before tripping.  Like a sergeant commanding his troops to “Wait for it!” the SIF designer is anxious that the SIF not trip prematurely. Some [...]

By |2018-03-08T15:01:42+00:00March 8th, 2018|Process Safety, Process Safety Management, Risk Assessment, Safety Lifecycle|Comments Off on Wait For It! Are Trip Delays Okay?
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