API 527 Seat Tightness of Pressure. Relief Valves

1992. American Petroleum Institute. Third Edition, July 1991. Reaffirmed, May 1996. This standard describes tests to determine the seat tightness of metal- and soft-seated pressure relief valves. Valves of conventional, bellows. and pilot-operated designs are covered.
Acceptable leakage rates are defined. Tests with air, steam, and water are described. This standard requires the purchaser to specify certain details and fearures. Although it is recognized that the purchaser may desire to modify, delete, or amplify sections of this standard. it is strongly recommended that such modifications. deletions, and amplifications be made by supplementing this standard, rather than by rewriting or incorporating sections thereof into another complete standard.