Nipple (plumbing) 3223727 199756717 2008-03-21T03:54:40Z ImageRemovalBot 4851336 Removing deleted [[:Image:Nipple quarter inch.jpg|image]] {{Refimprove|date=August 2007}}<!-- Deleted image removed: [[Image:Nipple quarter inch.jpg|thumb|right|150 px| Flow Calibrated 1/4" Nipple]] --> In [[plumbing]] and [[piping]], a '''nipple''' is a fitting, consisting of a short piece of [[pipe (material)|pipe]], usually provided with a [[gender of connectors and fasteners|male]] [[national pipe thread|pipe thread]] at each end, for connecting two other fittings. The length of the nipple is usually specified by the overall length with threads. It may have a hex section in the center for wrench to grasp. A "close nipple" has no unthreaded area; when screwed tightly between two female fittings, very little of the nipple remains exposed. A close nipple can only be unscrewed by gripping one threaded end with a [[pipe wrench]] which will damage the threads{{Fact|date=August 2007}} and necessitate replacing the nipple, or by using a specialty tool known as a [[Nipple wrench (plumbing)|nipple wrench]] (or known as an internal pipe wrench) which grips the inside of the pipe, leaving the threads undamaged. When the ends are of two different sizes it is called a reducer or unequal nipple. A barrel nipple or a pipe nipple is one which is usually made from pipe and is threaded only at both ends. Threads used on Nipples are BSP, BSPT, NPT, NPSM and rarely{{Fact|date=August 2007}} Metric. ==See also== * [[Coupling (piping)]] * [[Street elbow]] ==Further reading== *ASTM A733-03 Standard Specification for Welded and Seamless Carbon Steel and Austenitic Stainless Steel Pipe Nipples. *ASTM B687-99(2005)e1 Standard Specification for Brass, Copper, and Chromium-Plated Pipe Nipples. *ASME B1.20.7 Hose Coupling Screw Threads, Inch. (Quote: ''The normal sequence of connections, in relation to the direction of flow, is from an externally threaded nipple into an internally threaded coupling'') [[Category:Plumbing]] [[Category:Piping]] [[tr:Nipel]]