Red Seal Plumber key terms

A dimensionless value assigned to each plumbing fixture that reflects its probable peak drainage load and water supply demand, allowing dissimilar fixtures to be compared when sizing pipe.

The total measured distance a pipe run follows, including all offsets, risers, and fittings, used to calculate friction loss and determine vent and drain sizing limits.

The slope of the pressure line along a pipe or drainage system, showing how much pressure is lost per unit of length as water flows through it.

Pressure lost as water moves through pipe, fittings, and valves because of resistance at the pipe wall; it increases with flow rate, pipe roughness, and the number of fittings.

A method of expressing the resistance of fittings and valves as an added length of straight pipe, so total pressure loss can be calculated in one step.

The total fixture-unit value of all fixtures connected to a drainage branch or stack, used to select pipe size from sizing tables.

A vertical pipe that carries soil or waste downward, or carries vent air upward, through one or more storeys of a building.

A horizontal or sloping pipe that connects one or more fixtures to a stack, building drain, or other main line.

The portion of a fixture drain between the trap weir and the point where it connects to a vented branch or stack, limited in length to protect the trap seal.

The depth of water held in a trap that blocks sewer gas from entering a building; it is measured from the trap weir to the top of the dip.

A device or arrangement that automatically adds water to a floor drain or similar trap that would otherwise dry out from infrequent use, keeping the seal intact.

A vertical vent pipe that provides air to a drainage stack or branch so trap seals are not siphoned, extending through the roof or connecting to another vent.

A one-way valve that admits air into a drainage system when pressure drops, protecting trap seals without requiring a vent pipe through the roof.

An accessible fitting with a removable plug or cover that allows a drain line to be rodded or inspected where blockages are likely to occur.

The lowest horizontal piping of a drainage system, which receives soil and waste from stacks and branches and carries it to the building sewer.

The pipe that runs from the end of the building drain to the public sewer, private disposal system, or other point of disposal.

A valve installed in a drainage line that closes automatically when flow reverses, preventing sewage from backing up into a building during sewer surcharge.

The pipe that brings potable water from the municipal main or private source to the building, ending at the first valve or fitting inside.

A device installed on the service line that measures the volume of water passing into a building for billing and leak detection.

A regulator that lowers incoming water pressure to a safe, stable level for the building's piping and fixtures, protecting them from excess stress.

Any actual or potential link between a potable water supply and a source of contamination, which must be controlled to protect drinking water.

An assembly that stops water from reversing direction in a supply line, protecting potable water from contamination caused by backpressure or backsiphonage.

The unobstructed vertical distance between the lowest point of a water outlet and the flood level rim of the receiving vessel; the most reliable backflow protection.

A device that opens to atmosphere when supply pressure drops, breaking a vacuum that could siphon contaminated water back into the potable supply.

A loud banging or shock in piping caused by a sudden stop in water flow, producing a pressure surge that can damage joints and fixtures.

A capped chamber containing a cushion of air or a piston that absorbs the pressure surge created when a valve closes quickly.

The increase in water volume as it is heated in a closed system, which raises pressure and requires a means of relief such as an expansion tank.

A vessel with a compressed air charge that accepts the extra volume of water created by heating, limiting pressure rise in a closed plumbing system.

A safety device on a water heater that opens to discharge water if temperature or pressure exceeds set limits, preventing a tank rupture.

An appliance that heats and stores potable water for domestic use, including tank and tankless types, each with specific venting and relief requirements.

The pipe that runs from a fixture's trap to the branch or stack, carrying wastewater away from the fixture.

A pressure test in which a system is filled with water and held under pressure to reveal leaks before the piping is covered or put into service.

A test that pressurizes a piping system with air or inert gas to check for leaks, often used where water would be impractical or damaging.

A test in which smoke is forced into a drainage system to locate leaks, broken pipes, or improper connections that allow sewer gas to escape.

A procedure that applies a specified pressure to a completed system or section and holds it for a set time to confirm joints and components are leak-free.

A joining method for copper tube in which molten solder is drawn into the gap between tube and fitting by capillary action after fluxing and heating.

A cold joining method that uses a tool to compress a fitting with an O-ring seal onto pipe, avoiding open flame and heat.

A method of joining plastic pipe and fittings by applying solvent cement that softens the surfaces so they fuse together as the joint sets.