API STD 641 : 2023

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.