API Standard 621

API Standard 621

API Standard 621 is a Recommended Practice (RP) that describes guidelines for reconditioning metallic gate, globe, and check valves.

Scope

API 621 RP provides guidelines for reconditioning heavy wall carbon steel, ferritic alloy, stainless steel, and nickel alloy gate, globe, and check valves for ASME pressure classes up to 2500. The guidelines apply to flanged and butt weld cast or forged valves.

Valve specifications

The standard describes specifications pertaining to the repair of the following valve parts:

Handwheel nut
Handwheel
Yoke
Stem nut and stem nut housing
Stem nut retainer
Packing gland flange
Packing gland
Back seat bushing
	Bonnet stuffing box
	Castings
	Body-to-bonnet flanges and gasket surfaces
	Body end flanges, gasket surfaces, and face-to-face dimensions
Body and bonnet
Body guides
Body seat rings
Wedge guides
Wedge, globe, disc, and clapper
Stem
Body-to-bonnet joint bolting
Packing gland eye bolts
Packing
Body-to-bonnet joint gasket

The standard also provides guidelines for post-repair assembly, pressure testing, and shipping.

A full copy of API 621, with complete recommendations for reconditioning metallic gate, globe, and check valves, can be purchased from the American Petroleum Institute.