Typical Sizing / Selection Data

The following is a suggested list of service conditions which must be provided in order to properly size and select a pressure relief valve. We have provided a typical Pressure Relief Valve “Specification Sheet” for your use.

1. Fluid Properties:

a. Fluid and State

b. Molecular Weight

c. Viscosity

d. Specific Gravity
Liquid (referred to water)
Gas (referred to air)

e. Ratio of Specific Heats (k)

f. Compressibility Factor (Z)

2. Operating Conditions:

a. Operating Pressure (psig maximum)

b. Operating Temperature (°F maximum)

c. Max. Allowable Working Pressure (psig)

3. Relieving Conditions:

a. Required Relieving Capacity
Gas or Vapor (lb/hr)
Gas or Vapor (scfm)
Liquid (gpm)

b. Set Pressure (psig)

c. Allowable Overpressure %

d. Superimposed Back Pressure (psig)

(specify constant or variable)

e. Built-Up Back Pressure (psig)

f. Relieving Temperature (°F)