Nipple (plumbing)


In plumbing and piping, a nipple is a fitting, consisting of a short piece of pipe, usually provided with a male pipe thread at each end, for connecting two other fittings.
The length of the nipple is usually specified by the overall length with thread. It may have a hexagonal section in the center for a wrench to grasp, or it may simply be made from a short piece of pipe. 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 and necessitate replacing the nipple, or by using a specialty tool known as a nipple 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.
Threads used on nipples are BSP, BSPT, NPT, NPSM and Metric.

Chase nipple

A chase nipple is a short pipe fitting, which creates a path for wires between two electrical boxes. A chase nipple has male threads on one end only. The other end is a hexagon. The chase nipple passes through the knockouts of two boxes, and is secured by an internally threaded ring called a lock nut.
Chase-Shawmut Company, of Boston, is the company which first produced chase nipples.