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Pressure Relief Devices

Print Date: 12/11/2017 5:04:10 AM

Pressure relief devices are used to provide a means of venting excess pressure which could rupture a boiler or pressure vessel. A pressure relief device is the last line of defense for safety. If all other safety devices or operating controls fail, the pressure relief device must be capable of venting excess pressure.

There are many types of pressure relief devices available for use in the boiler and pressure vessel industry. This inspector guide will address the most common devices found on boilers and pressure vessels. Virtually all jurisdictions require a pressure relief device to be manufactured and certified in accordance with the ASME BPV Code in addition to being capacity-certified by the National Board.

The most common types of pressure relief devices are:

Pressure relief devices must operate as designed in order to perform their required task. Different types of problems can prevent normal operation:


While inspecting a boiler or pressure vessel, the inspector will also be evaluating the pressure relief device(s) installed on, or associated with, the equipment. The inspector should:


Additional information to aid inspections of pressure relief devices, including installation requirements, can be found in the following publications and sources: