Polybutylene plumbing inside a structure ("PB
In-House Plumbing") is a potable water supply system containing
polybutylene ("PB") pipe and either acetal
(plastic) or metal insert fittings (such as tees, and elbows). PB
pipe is a non-rigid, sometimes curved, usually gray (or possibly silver or
black) plastic pipe. When used in the underground service from the water
company to a structure (a "Yard Service Line"), PB pipe is blue,
gray or black. PB pipe is not used for drains, waste or vent piping. Also,
PB pipe is not PVC or CPVC, which is a rigid white or off-white plastic
pipe. "PB Plumbing" refers to both PB In-House Plumbing and Yard
Service Line.
Insert fittings are used to join pieces of polybutylene pipe. The insert
fitting is inserted into the pipe and clamped with a metal (aluminum or
copper) crimp ring over the outside of the pipe. Metal insert fittings are
either copper or brass. Acetal insert fittings
are hard gray or white plastic. They are not black. Insert fittings are
not grabber, flare or compression fittings, which are often threaded and
use a plastic or metal nut to secure the seal.
