Relief Valve Sizing

API 520 / API 521 pressure relief valve orifice sizing for gas service

Required Flow W (kg/h)

Relieving Temp T (K)

Compressibility Z

Mol Weight M (g/mol)

Set Pressure P₁ (kPa)

Kd (discharge coeff)

Kb (backpressure)

Kc (comb. cap)

Required Orifice Area

36.4554 mm²