This article is the second in a two-part series describing the certification process for pressure relief devices (PRDs). In this article, the testing process for PRDs is explained. Part One (published in the fall 2017 issue) examines the overall process of certification from start to finish. When inspecting pressure relief devices, one of the most important features on the device nameplate is the ASME code stamp with a designator symbol below it. This ASME code stamp is paired with a National Board NB mark, which shows that the device is an ASME-accepted and National Board-registered design, and was constructed by an organization accredited by ASME for the manufacture or assembly of pressure relief devices. In the case of a repaired valve, the valve may also be required to bear a repair nameplate with a VR stamp, which indicates the repair was performed by a National Board-accredited valve repair organization. Devices tested for proper operation, but not repaired, may bear the Test Only T/O mark if the testing was performed by a National Board-accredited testing organization.
展开▼
