The American Petroleum Institute (API) 521 Standard on “Pressure-relieving and Depressuring Systems” provides a method to estimate the sound pressure level (Lp) of a pressure safety valve venting to atmosphere.
This vent noise calculator is based on the API 521 noise estimation method, and allows the user to estimate the sound pressure level at 30 metres, as well as at any user specified distance (within the limitations of the method) by following these steps:
- Calculate pressure ratio and estimate sound intensity
- Estimate the sound pressure level at 30 metres from the vent based on the speed of sound in the fluid (c) and fluid mass flow rate (qm)
- Estimate the sound pressure level at a user specified distance from the vent (Lp30)
To use the calculator, follow the steps below, providing the necessary inputs.