懒虫工控（旧）

标题: PFDavg [打印本页]

作者: 王天泽 时间: 2018-1-26 19:01
标题: PFDavg

Probability of Failure on Demand average- This is the probability that a system will fail dangerously, and not be able to perform its safety function when required. PFD can be determined as an average probability or maximum probability over a time period. IEC61508/61511 and ISA84.01 use PFDavg as the system metric upon which the SIL is defined。

Also Process Flow Diagram. A diagram of the basic process equipment usually accompanied by a heat and material balance. Typically prepared early in an engineering project, it is usually part of the input to a HAZOP or other hazard identification process。

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