NC Plumbing Contractor key terms

A credential issued by the state or local authority that allows a person to design, install, and supervise plumbing work and to serve as the qualifying individual for a plumbing contracting business.

Approved coursework hours a licensed plumber must complete during each renewal cycle to keep the license active and stay current with code changes and trade practices.

Written authorization from the code authority allowing a specific installation, alteration, or repair of plumbing work at a given address, issued before work starts so the job can be inspected.

A change adopted by a city, county, or state that modifies or adds to the model plumbing code within that jurisdiction; where requirements differ, the stricter provision generally controls.

A formal request to use a material, design, or installation technique that departs from the prescriptive code, approved only when the code official determines it is equivalent in safety and performance.

A unit of measure expressing the probable hydraulic load a fixture places on the drainage or water supply system, based on its discharge rate and how long it typically runs.

The vertical distance between the trap weir and the top of the trap dip, measured as inches of water that must be maintained to keep sewer gas from entering the building.

The building drain is the lowest piping inside the building that receives soil and waste, ending where it exits the foundation; beyond that point the same run is called the building sewer.

The main vertical drainage pipe that carries the discharge from water closets and other fixtures down to the building drain, rising at least one story in height.

A vertical vent pipe connected to a drainage stack that supplies air so traps keep their seals and wastewater moves freely, usually terminating in open air above the roof.

A pipe that acts as the drain for one fixture and at the same time as the vent for another, allowed only within code limits on size, length, and fixture arrangement.

A one-way mechanical valve that opens under negative pressure to admit air into the drainage system and closes to stop sewer gas from escaping; it must be accessible and installed as listed.

An accessible fitting with a removable cap or plug that gives maintenance access to a drainage line for clearing stoppages, required at specified points and intervals along the piping.

A device installed in a drainage line that closes automatically when flow reverses, stopping sewage from a surcharged public sewer or building drain from backing up into the building.

The downward pitch of a horizontal drainage pipe, expressed as inches of fall per foot of run, that produces gravity flow fast enough to carry solids without clogging.

The pipe that carries potable water from the public main or private well to the building, ending at the meter or at the first shutoff valve inside the structure.

A device that lowers incoming street water pressure to a safe, usable level downstream, protecting fixtures, appliances, and piping from excessive pressure and water hammer.

A capped chamber containing a trapped air cushion or a piston that absorbs the shock wave created when a valve closes quickly in a pressurized water line.

The increase in water volume as it is heated inside a closed system, which raises pressure and must be relieved by an expansion tank, relief valve, or other approved method.

The pressure still remaining in a water supply pipe at the point of use while water is flowing, which must stay at or above the code minimum for the fixture to function properly.

A safety device on a water heater that opens to release pressure or excessive temperature before unsafe levels are reached, and must be piped to a safe discharge location.

A fixture with a removable strainer set flush into the floor to receive surface water or indirect waste, fitted with a trap to keep sewer gas out of the space.

A valve that uses line pressure to deliver a measured flush to a water closet or urinal, requiring adequate supply pressure and a correctly sized fixture connection to work.

Any actual or potential link between the potable water system and a source of contamination or pollution, which can let unsafe water flow backward into drinking water.

The unobstructed vertical distance between the lowest point of a water supply outlet and the flood level rim of the fixture it serves; the most dependable form of backflow protection.

An assembly with two independent check valves and a relief valve that discharges if differential pressure is lost, used on potable lines serving high-hazard cross-connections.

A device that admits air into piping to break a siphon and stop backflow; atmospheric and pressure types are applied to hose connections, appliances, and similar outlets as the code allows.

A material classification meaning the wetted surface of pipe, fittings, or fixtures contains no more than the maximum lead content allowed by federal law for drinking water contact.

A single-view drawing that shows piping runs in three dimensions using angled lines, used to lay out drain, waste, vent, and water piping and to count fittings accurately.

The total length of a pipe measured along its centerline, including the extra length taken up by fittings and bends, used in sizing instead of horizontal distance alone.

The process of counting and measuring pipe, fittings, fixtures, and equipment from drawings and specifications to build a material list for pricing and ordering.

A written document signed by the owner and contractor that revises the scope, price, or schedule of an existing contract and becomes part of the contract documents.

A percentage withheld from each progress payment by the owner until the project reaches substantial completion or final acceptance, protecting the owner against incomplete or defective work.

A legal claim recorded against a property by a contractor or supplier who has not been paid for labor or materials, which can cloud the title until the debt is settled.

A written list of incomplete or defective items noted during the final walkthrough that the contractor must correct before final payment and project closeout.

A guarantee submitted with a bid assuring the owner that the bidder will sign the contract and furnish performance and payment bonds if the work is awarded.