API Std 641 Second Edition

API Std 641 PDF

This standard specifies the requirements and acceptance criteria for fugitive emission type testing of quarter-turn valves. Valves larger than NPS 60 and valves greater than ASME B16.34 class 1500 are outside the scope of this standard. Valves with a pressure rating at ambient temperature less than 6.89 barg (100 psig) are outside the scope of this standard. For all valves rated greater than or equal to 400 °C (750 °F), an additional high temperature test may be performed in accordance with Annex C or when specified by the purchaser.

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

API Standard 622, Type Testing of Process Valve Packing for Fugitive Emissions

ASME B16.34,1 Valves—Flanged, Threaded, and Welding End