# SCMH

Standard volumetric flow rates of a fluid are often used to describe the capacity of a vent or pressure relief device. To determine how this capacity compares for another fluid under different pressure and temperature conditions a conversion must be made on the basis of equivalent pressure loss. This article describes the method for calculating the volumetric flow rate of a gas which will give the equivalent pressure drop to another gas through a fixed restriction such as a vent.

Standard volumetric flow rates of a fluid are the equivalent of actual volumetric flow rates in the sense that they have an equal mass flow rate. This identity makes standard volumetric flow appropriate providing a common baseline for comparison of volumetric gas flow rate measurements at different conditions. This article outlines how to convert between standard and actual volumetric flow rates.