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…

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…

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,…

ASME Section VIII §UG-127(a)(2)1 indicates that the relieving capacity of a rupture disk used independently (that is, not on the inlet or outlet of a pressure relief valve) can be determined based on one of…

The analysis for the flow of liquids through pressure relief devices in API and ASME standards is currently predicated on the fluid viscosity behavior being Newtonian; API Std 520 Part I, 8th edition (2014), explicitly…

Sudden tube ruptures in shell and tube heat exchangers operating at a high differential pressure in which the low pressure side contains an incompressible fluid and the high pressure side contains gas have been recognized…

Inglenook received an e-mail the other day from a long-time client asking what references we used when specifying restriction orifices for several emergency blowdown systems we had designed a few years earlier.  The primary concern…

One of the more complex situations for control valve failure is associated with the level control on the liquid bottoms of an upstream vessel operating at a pressure significantly higher than the downstream system.  Opening…

Manufacturers of pressure relief valves are required to publish capacity data for their valves, and quite often this is translated into an effective coefficient of discharge (Kd).  These discharge coefficients are typically published for water…