- by Hal Thomas, CFSE
- Thursday, August 25, 2011
- Functional Safety
PHA to LOPA: Part I
Parts I and II of this article provide a framework for when it is appropriate to make the transition from qualitative analysis to more quantitative during the hazard review work process. It further illustrates that LOPA can be used as part of what is considered more qualitative analysis…
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- by Hal Thomas, CFSE
- Tuesday, May 24, 2011
- Functional Safety
When is a Variable Frequency Drive a SIS?
It used to be that a pump would operate at a single speed dictated by a motor, thus fixing the pump curve. As the discharge flow decreased due to a restriction downstream, the pump outlet pressure would increase reaching its deadhead pressure. If the downstream piping and vessels were…
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