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Entries tagged with: FIT

Back to Basics: Failure Rates - FIT

Back to Basics: Failure Rates - FIT

Failures ITime or Failure UnIT

FIT is the number of failures per billion hours for a piece of equipment. 

It is mentioned in both IEC 61508 and IEC 61511 standards as a preferred unit of measurement expressed by 109 hours.

Example: 5 FIT is expressed as 5 failures within 109 hours . 

When you…

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  • by Iwan van Beurden, CFSE
  • Tuesday, April 30, 2013
  • Certification

How Do You Certify to IEC 61508?

As you may already know, when it comes to the certification of equipment according to IEC 61508, there are several 3rd party agencies from which to choose. It is obvious from reviewing different assessments on for example a solenoid, that the interpretation of IEC 61508 and thereby the assessment…

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Why Does My Proof Test Coverage Change with Partial Stroke Testing?

I have run into this question a couple of times now and though the answer is somewhat straightforward, some customers have trouble wrapping their head around this without a clear example. So here we go…

First of all we need to keep in mind that the objective of a…

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