For overpressure protection systems involving only rupture disks (that is, not a rupture disk in combination with a pressure relief valve), the frictional losses throughout the piping system is typically used as a means for…

All control valves, regardless of their fail-safe position, have the potential to go wide open.  Failure open of an inlet control valve is typically considered an applicable overpressure scenario for a pressure vessel when the…

Pressure changes from protected equipment to a pressure relief valve (PRV) and from a PRV to the final relief effluent location are determined to allow an evaluation of the effect of the pressures on the…

In a reciprocating compressor, a failure of the packing material around the rod can allow high pressure gases from the cylinder to enter into the distance piece that separates the cylinder housing from the compressor…

API Standard 520 Part 1 9th Edition1 Annex B §B.3.1.2 provides an expression in equation B.13 for the isentropic expansion coefficient in terms of thermodynamic state variables, to be evaluated anywhere along the isentropic path,…

A subcooled yet flashing liquid, in which the vapor pressure is less than the relief pressure yet greater than the superimposed backpressure, represents an occasional non-ideal sizing condition, as the flow is neither fully liquid…

In a previous Fireside Chat, Orifice Flow Calculation Basis, we provided information on the flow of compressible fluids through sharp-edged orifices.  While that topic was primarily geared toward the flow of gases through an orifice…

The 2nd edition of the CCPS Guidelines for Pressure Relief and Effluent Handling1 recommends the work of Darby2 for use in evaluating relief piping systems.  We have already touched on the recommendations regarding roughness factors. …

There are a number of methods available for estimating the capacity of a pressure relief valve for a two-phase relief fluid.1,2  One primary distinction among these methods is the means for representing fluid property behavior,…

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…