Plumbing Terminology - F

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | Y

Face Seal

A face seal is typically incorporate an O-ring that mate against the face of the opposite connector to form the seal. Depending on the standard, the O-ring may be on the nose of the male threaded connector, or behind the male thread on the face of the backing nut.


A ferrule is a sleeve-type fitting that slip over two ends to join them together. These fittings can be compressible and used as the sealing component of a compression fitting. They are also used as weldable connection fittings.

First Draw

With first draw is meant the water that has been sitting in pipes or plumbing fixtures overnight and is first drawn when taps are opened in the morning. For instance, where lead is present in plumbing, this water would have the highest levels of lead contamination.

Fixture Branch

A fixture branch is a pipe that carries wastes from non-toilet plumbing fixtures directly to the building drainage system. It is also called a waste pipe, wet vent, or a fixture drain.

Fixture vent

In the plumbing trade fixture vents are used to ventilate plumbing fixtures, to prevent siphonage, to relieve pressure on trap seals, and to draw off back pressure from gases generated by decomposing sewage. It is usually run as a continuous vent, that is, only one fitting is used to connect vent pipe, waste pipe, and fixture trap or branch.


In the plumgbing and piping industry a flange is a plate or ring to form a rim at the end of a pipe when fastened to the pipe (for example, a closet flange). A blind flange is a plate for covering or closing the end of a pipe. A flange joint is a connection of pipes, where the connecting pieces have flanges by which the parts are bolted together.

Flapper Flush Ball

A Flapper Flush Ball is the moving part of the flush valve that seals the water into the tank or allows water to exit the tank for the flush cycle. The most common replacement part used on conventional toilets.

Flex Coupling

A Flex Coupling is the rubber coupling used to join DWV Pipe. Can be used to connect PVC to Clay or Cast Iron above or below ground. Also used for repairs, and attach by used of steel band clamps.

Flow Control Valve

A flow control valve is a device designed to reduce water flow to a plumbing fixture. Often used to improve efficiency and reduce operating costs. Also a check valve that prevents flow reversal when heater is turned off.