scope:

This recommended practice is intended to apply to relieving devices and their discharge systems on refinery pressure vessels and equipment designed for maximum allowable working pressure of more than 15 pounds per square inch. Steady state of flow and Newtonian fluids are assumed in flow formulas.

Storage vessels covered by API Standards 2000: Guide for Venting Atmospheric and Low-Pressure Storage Tanks and pressure vessels used for transportation of petroleum products in bulk or in shipping containers are not within the scope of this recommended practice.

Inasmuch as pressure-relieving devices protect a vessel only against overpressure and not against a bursting failure when exposed to fire, means are suggested for reducing the pressure to near atmospheric pressure and for restricting the heat input. Additional information supplementing the text discussion is presented in Appendixes A through C.