ICC P2 key terms

The complete assembly of potable water supply and distribution piping, fixtures and fittings, water heaters, drainage and vent piping, and storm drainage serving a building, together with their joints, connections, and appurtenances.

The officer, authority, or authorized representative designated by the jurisdiction to administer and enforce the plumbing code, including reviewing plans, issuing permits, and inspecting installed work.

Acceptable to the code official. Materials, methods, or equipment become approved through investigation, testing, or compliance with a recognized standard showing the item meets the code's intent.

Described in a current list published by an approved testing agency that periodically inspects production and confirms the equipment or material complies with a designated recognized standard.

A receptacle or device permanently or temporarily connected to the water supply that demands water and receives liquid or liquid-borne waste discharged into the drainage system.

A flushable plumbing fixture that receives human body waste and discharges it through a trap into the drainage system, typically a toilet.

An appliance that heats potable water for domestic use and delivers it to the distribution system; types include storage tank, instantaneous, and heat exchanger models.

A valve on a water heater that opens automatically and discharges water when internal temperature or pressure exceeds its setting, preventing the tank from rupturing.

The top edge of a fixture, receptor, or receptacle where water would overflow onto the floor; used to establish air gap and backflow protection heights.

A drainage fitting set flush with the floor that collects surface water and wash-down and connects through a trap to the drainage system.

Water that is free of impurities in amounts sufficient to cause disease or harmful physiological effects and that meets the drinking water quality standards of the authority having jurisdiction.

The pipe that carries potable water from the public water main or other source of supply to the building's water distribution system.

The unobstructed vertical distance through free atmosphere between the lowest opening of a water supply outlet and the flood-level rim of the fixture or receptor it serves.

The reversal of normal flow in a potable water piping system, so that nonpotable water, waste, or gas can be drawn or pushed into the drinking water supply.

Any actual or potential link between the potable water system and a source of contamination or pollution, including piping, fixtures, or equipment through which backflow could occur.

A backflow preventer with an air inlet that opens to the atmosphere when supply pressure drops, breaking a siphon; it must be installed where not subject to continuous pressure.

A testable backflow prevention assembly containing two independent check valves with a hydraulically operated differential relief valve between them, used for high-hazard cross connections.

A unit of measure expressing the probable demand a plumbing fixture places on the water supply system, used with sizing tables to select pipe sizes.

A closed tank, often fitted with a bladder, installed on a closed water system to absorb the extra volume created as water is heated and expands.

A fitting or device that holds a liquid seal to stop sewer gases from entering a building while still allowing waste water to flow through.

The depth of liquid held in a trap, measured between the crown weir and the dip, which blocks sewer gas from passing into the building.

The section of fixture drain running from the trap weir to the point where the fixture is vented; its length and slope are limited to prevent self-siphonage of the trap.

A device or piping arrangement that automatically delivers small amounts of water to a trap to replace evaporation and keep the seal intact.

A scale used to express how much waste a fixture discharges into the drainage system, with one unit commonly taken as about one cubic foot per minute of flow.

The lowest piping of a building's drainage system, receiving soil, waste, and other drainage pipes inside the building and carrying the discharge to the building sewer.

The pipe that carries sewage from the end of the building drain to the public sewer or another approved point of disposal.

A vertical drainage pipe that receives the discharge from water closets and carries it down to the building drain.

A vertical vent pipe that supplies air to a soil or waste stack, relieving back pressure so that trap seals in the stack are not siphoned.

The extension of a soil or waste stack above the highest horizontal drain connected to it, terminating in open air above the roof.

A vent that also serves as a drain for fixtures other than the ones it vents, so it must be sized and installed to carry both air and waste water.

A one-way valve that admits air into the drainage system to equalize pressure when water flows and closes tightly to keep sewer gas in the pipe; allowed only where the code permits.

An accessible fitting with a removable plug or cover, installed in drainage piping so that the line can be rodded and inspected.

A device in a drainage line that closes automatically when flow tries to reverse, keeping sewage from a surcharged public sewer out of the building.

A receptacle that separates fats, oils, and grease from kitchen waste water so the grease can be removed before the effluent enters the building sewer or public sewer.

A receptacle set into or on a roof surface that collects rainwater through a strainer and leads it into the storm drainage piping.

A vertical pipe that carries storm water from roof drains, gutters, or scuppers down to the storm drainage system or building storm drain.

A sewer that conveys only storm water, surface water, and groundwater, with no sanitary sewage or industrial waste.

A pump installed in a pit or sump that removes accumulated water, such as groundwater or building drainage, and discharges it to an approved point of disposal.

Water that is not safe or approved for drinking or human consumption, such as harvested rainwater, graywater, or reclaimed water used for flushing, irrigation, or cooling.