API - SPEC 6D
Specification for Pipeline Valves (Gate, Ball, and Check Valves)
|Publication Date:||31 March 1994|
Coverage. This specification covers flanged and butt-welding gate, plug, ball, and check valves.
Codes, Specifications, and Standards. Each code, specification, or standard referenced herein shall be the latest edition or supplement in effect at the time of manufacture of the product.
Bidirectional Valve: A valve designed for sealing in either direction.
Block Valve: A gate, plug or ball valve that prevents flow or leakage into the downstream conduit when in the closed position. Valves shall be single or double seated, bidirectional or unidirectional. Unidirectional valves shall be marked with a flow direction arrow.
Closure Member: That part of a valve which is positioned in the flow stream to permit, obstruct or regulate flow.
Double Block and Bleed Valve: A valve with two seating surfaces which, in the closed position, provides blockage of flow from both valve ends when the cavity between the seating surface is vented or drained. A means shall be provided for draining or venting the cavity between the seating surfaces.
Extended Operating Gear: An operating means located above its normal position on a valve, to allow above-ground access when the valve is installed below ground.
Handle Extension: A length of bar or pipe used to manually operate a plug or ball valve. The handle extension is sized to fit the head. The handle extension is separable from the head that is attached to the valve stem.
Handwheel: A wheel consisting of a rim connected to a hub by spokes, which is used to manually operate a valve requiring multiple turns.
Locking Device: A part or an arrangement of parts providing a means to secure a valve in the open or closed position.
NPS: Abbreviation for Nominal Pipe Size in inches.
Position Indicator: A device to show whether a valve is in the open or closed position.
Pressure-Containing Parts: Those parts whose failure to function as intended would result in a release of retained fluid to the atmosphere such as bodies, bonnets, and stems.
Raised Face: A flange face having a flat surface protruding 1/16 or ¼ inch beyond the outer flange face.
Ring Joint Face: A flange face having a specially shaped groove located between the bolt holes and the flange bore.
Seating Surfaces: The contact surfaces of the closure member and seat which effect valve closure.
Support Ribs or Legs: A metal structure attached to a valve body to provide a stable footing when the valve is to be set on a fixed base.
Unidirectional Valve: A valve designed for sealing in one direction only.
Venturi Plug Valve: A valve with a substantially reduced opening through the plug, in which the transition from each full opening end to the reduced opening is well streamlined.
Wrench A device for manually operating a plug or ball valve consisting of a length of pipe or bar with one end prepared to fit the valve stem.