Interactive Tool

Pressure Safety Valve (PSV) Sizing

Calculate and size Relief Valve Orifices for Gas/Vapor Relief according to API RP 520 Part I. Ensures safe overpressure protection.

1. Input Parameters

Relief Load (W)

kg/h (Mass flow rate)

Relief Temp (T)

°C (Operating relieving temp)

Set Pressure

barg (PSV Set Pressure)

Overpressure (%)

Default is 10% for process fire/liquids

Molecular Weight (M)

g/mol (e.g. Propane = 44.1)

Specific Heat Ratio (k)

Cp/Cv ratio (Default 1.13)

Compressibility Factor (Z)

Default is 1.0 (Ideal gas)

Discharge Coeff (Kd)

Default 0.975 for API Gas/Vapor

Calculated Orifice Area

0.00 mm²

Required minimum area based on inputs.

Designation	Standard Area (mm²)	Status