Relief Valve Sizing

The relief valve program is not based on any specific standard or code. However all the various standards are all based on two fundamental assumptions:

• The flow from the pressure vessel to the throat of the relief valve is isentropic.

• The gas isentropic expansion law can be expressed using the following formula: , where k is the isentropic exponent (often estimated as )

So, while this program is not aligned to any specific code, it nevertheless yields near identical answers when sizing relief valves. What it doesn't provide are the specific limitations based on specific rules.