A systematic evaluation and identification of safe operating limits is useful in maintaining efficient and effective operations, meeting environmental restrictions, and ensuring process safety, yet efforts to implement compliance with this PSM element1 suffer from…
Read More »The periodic verification of the relief system design and design basis is good practice, but does not mean an operator must re-perform the Pressure Relief Analysis (PRA) at each cycle. Similar to the verification of…
Read More »There are multiple sources of vibration in piping that can lead to failures, usually occurring at welds, penetrations, or other ‘discontinuities’. The EI Guidelines for the Avoidance of Vibration Induced Fatigue Failure in Process Pipework1…
Read More »Many of the relieving requirements for credible overpressure scenarios we calculate implicitly assume that the only mass/energy allowed to leave the system is through the relief device; however, there are some instances of reasonable attempts…
Read More »API Standard 521, 6th Edition, §4.4.12.4.1 provides an equation (shown below) for the calculation of the pressure rise due to hydraulic expansion of a non-boiling liquid1. The calculation is comprised of four basic components: the…
Read More »We recently encountered cases where the corrected hydrotest pressure needed to be determined, and thought it would be useful to share the calculation process. The cases in question were various tube ruptures potentially affecting a…
Read More »The Center for Chemical Process Safety (CCPS) defines process safety time as “the time period between a failure occurring in the process or its control system and the occurrence of the hazardous event.”1 Process safety…
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