API St 622-2011 pdf free download

API St 622-2011 pdf free download.Type Testing of Process Valve Packing for Fugitive Emissions.
3.11 die-formed packing A valve stem packing typically constructed from ribbons of graphite tape or braided packing that has been subjected to pre-compression with tooling of a specific geometry. This process changes the shape and density of the material from its original free shape and natural density to a defined shape and higher density. 3.12 EPA Method 21 A leak check method established by the Federal Government Environmental Protection Agency (EPA) for performing emissions measurements on equipment such as valves, pumps, and flanges. 3.13 eccentricity The distance that the central axis of a valve stem is offset from the central axis of the stuffing box through which it passes. 3.14 emissions Gaseous leak given off by a piece of equipment. Used in reference to volatile organic hydrocarbons (VOCs) and expressed in parts per million volumetric (ppmv or ppm). 3.15 galvanic corrosion An electro-chemical reaction that may occur between a metal and a material of a different chemical nobility, such as another metal, carbon, or graphite when both materials are exposed to an electrically conductive media. See also, active inhibitor, corrosion inhibitor, passive inhibitor, pitting. 3.16 gland A movable part which protrudes into a stuffing box to compress a packing set or packing ring. 3.17 gland load The amount of load applied to a packing set. 3.18 gland stud A threaded rod or eye-bolt, extending from a valve body against which the gland flange is tightened to compress a packing set. 3.19 leak Measurable amount of test fluid escaping from the test gland. 3.20 leak rate The quantity of test fluid passing through (or around) a seal in a given period of time. 3.21 mechanical cycle A motion of the stem simulating the movement of a valve obturator (such as disc or ball) from the fully closed position to the fully open position, and returning to the fully closed position. See also, stroke.
3.22 packing set A grouping of individual packing rings designed to fill the cavity of the valve stuffing box. 3.23 passive inhibitor A type of galvanic corrosion inhibitor blended into the raw graphite used in packing, providing a protective coating to prevent a galvanic reaction from occurring. See also, active inhibitor, corrosion inhibitor, passive inhibitor, pitting. 3.24 pitting Surface cavities that occur on a metal as a result of galvanic corrosion or mechanical erosion. See also, galvanic corrosion. 3.25 rising stem valve A valve in which the movement of the stem is in an axial direction, with no rotation. 3.26 rotating stem valve A valve that will fully open or close with a nominal 90° rotation of the stem. 3.27 spacer bushing See bushing. 3.28 stem A metal rod that connects the obturator (such as a disc or ball) of a valve to a handwheel, handle, or actuator. 3.29 stroke One half of a mechanical cycle starting from either a fully open or fully closed position. See also, mechanical cycle. 3.30 stuffing box A space into which a compression packing is inserted. Also known as a packing chamber. 3.31 surface finish A measure of the roughness of a surface typically expressed in micro-inches or micro-meters.
4 Fugitive Emissions Test 4.1 Test Fixture 4.1.1 The test stand packing gland is constructed as a fixture designed to simulate a typical valve. A test gland arrangement with a combined leak detection and gland flange is shown in Figure 1. The test fixture shall orient the stem in a horizontal position and shall be constructed so as not to affect test results. The use of bushings is allowed as necessary. Test stands may be equipped with multiple test fixtures. See Annex B for construction details.