Relief valve sizing calculator

Relief valve sizing calculator mainly carries out calculations based on equations specified by American petroleum institute. The equations allow engineers to size relieve devices that can be used for different industrial applications.

Relief valve sizing calculator main features

The software will carry out calculations based on equations used in API 520 “7th Edition” and API 521 “4th Edition”. A list of main features is below;

  1. Support SI and US Units of measurements, with the ability to make input in different measurement units for Volumetric flow rate, Mass Flow rate, Temperature, Viscosity and Pressure.
  2. Sizing conventional and pilot operated relief valves for gas or vapour relief.
  3. Sizing conventional and pilot operated relief valves for liquid relief.
  4. Sizing conventional and pilot operated relief valves for saturated and superheated steam relief.
  5. Sizing conventional and pilot operated relief valves for vaporizing liquids (wetted vessels)
  6. Evaluate multiple cases in one go.
  7. Save and load your input.
  8. Copy results and paste it anywhere in any document
  9. Generate a summary report which can be printed or saved in different formats “Excel, Word and PDF”
  10. Calculated variables are based on input and service, mainly the following variables are calculated for all services; Relieving Pressure, Required effective discharge area, Actual discharge area, Equivalent Orifice diameter of device, Installed Relief rate and Designation. More calculated variables are displayed depending on selected service and input parameters.
  11. For vessel fire case (Vaporizing liquids – wetted vessels) the software will also calculate the rate of vaporization, the total heat absorption and the total wetted area. Calculations support both vertical, horizontal and spherical vessel orientation.


pressure relief valve calculator

Click here to download the demo version of the product. Please also note that the demo version of this software will only operate with set examples which are restricted in our demo version, the examples can be modified if needed however the set pressure is enabled.  The full version of this product does not have any restrictions.

We don’t offer a fully working demo version.

Screen Shot

Relief valve calculator
Fire case

For more software screen shots please follow the screen shots page available

Demonstration video clip on YouTube (Older version of Relief valve calculator)

To see an example for sizing a valve for vapor service and sizing a valve for vaporizing liquids (wetted vessels) – fire case please click here

video clips are also available to view on this website

System Requirements

This software needs the following computer configuration to run:

Microsoft Windows operating system (Windows 7, Windows 8.1, Windows 10, Windows 11)

64MB RAM Minimum, 30MB free disk space, Microsoft .Net 4.8 installed