ASSE 5140 key terms

Any unwanted reversal of normal water flow direction in a piping system, caused by backpressure or backsiphonage, that can carry contaminants into the potable supply.

Backflow produced when negative or sub-atmospheric pressure develops in a supply line, drawing nonpotable fluid into the potable system through an unprotected connection.

A condition where downstream pressure exceeds supply pressure, pushing water backward through a connection; commonly caused by pumps, boilers, or elevated tanks.

Any actual or potential physical link between a potable water system and a source of contamination or pollution, allowing unwanted material to enter drinking water.

The unobstructed vertical distance between a water supply outlet and the flood level rim of the receiving fixture, providing the highest level of backflow protection.

A testable backflow preventer with two independently acting check valves and a hydraulically operating differential relief valve, used for high-hazard protection against both backpressure and backsiphonage.

A testable backflow preventer with two independent check valves used to protect against low-hazard cross-connections where backpressure may occur.

A device that admits air into a piping system when internal pressure drops below atmospheric, breaking a siphon and preventing backsiphonage.

The top edge of a fixture or receptor from which water would overflow onto the floor, used as the reference point for air gap and air break measurements.

A drain pipe discharging into a receptor with a fixed vertical separation, preventing sewage backup from entering the fixture while not providing potable-water protection.

A dimensionless measure expressing the probable peak drainage load or water demand of a plumbing fixture relative to a standard fixture, used to size pipes.

A value assigned to a fixture representing its rate of discharge into the drainage system, used to determine pipe sizes for building drains and sewers.

A value reflecting the probable demand a fixture places on the water distribution system, used to size supply piping and determine pressure requirements.

The lowest horizontal piping of a drainage system that receives soil and waste from inside the building and conveys it to the building sewer.

The piping that carries sewage from the building drain to the public sewer, private disposal system, or other point of disposal.

A fitting or device that retains a water seal to prevent sewer gases from entering a building while allowing waste to pass through.

The vertical depth of water held in a trap that blocks sewer gas; it must be maintained within specified limits to resist evaporation and siphonage.

The portion of a fixture drain between the trap weir and the vent fitting, limited in length and fall to prevent self-siphonage of the trap.

Piping installed to provide air circulation to a drainage system, protecting trap seals from siphonage and allowing gases to escape outdoors.

A vertical vent pipe extending through the roof that serves one or more soil or waste stacks, equalizing pressure and relieving trap seals.

A one-way valve that opens to admit air into drainage piping when pressure drops and closes to prevent sewer gas escape; permitted only under stated conditions.

A loud banging or pressure surge in piping caused by the sudden stopping of water flow, often at quick-closing valves, requiring arrestors or cushioning devices.

A device that lowers incoming water pressure to a safe, usable level for the distribution system, protecting fixtures and piping from excessive stress.

The increase in water volume as it is heated, which raises pressure in a closed system and requires a relief valve or expansion tank for safety.

A safety device on a water heater that opens to release water when temperature or pressure exceeds safe limits, preventing tank rupture.

An appliance that heats potable water for domestic use, requiring proper relief protection, venting, and connection to the distribution system.

Liquid waste that discharges into a drainage system through an air break or air gap rather than a direct connection, protecting against contamination.

A general term for any vertical pipe in a drainage or vent system, including soil, waste, and vent stacks that serve multiple floors.

The introduction of any substance into potable water that renders it unfit or unsafe for human consumption, including toxic or health-hazardous materials.

A small valued opening on a backflow preventer used during field testing to check pressure and verify proper operation of the assembly.

The pre-construction examination of submitted drawings and specifications by the authority to confirm compliance with applicable plumbing and mechanical codes before permitting.

Official written authorization issued by the authority having jurisdiction to perform plumbing or mechanical work under stated conditions and inspections.

An on-site examination by a code official at required stages of construction to verify that work meets code and approved plans before it is covered or placed in service.

The stage of installation where piping, fittings, and connections are in place but not covered or finished, allowing inspection before concealment.

The organization or individual responsible for enforcing code requirements, approving materials and methods, and issuing permits and inspections.

Water that is safe for human consumption and domestic use, meeting health-based quality standards and protected from contamination throughout the system.

The network of pipes, valves, and fittings that conveys potable water from the source or meter to fixtures at adequate pressure and volume.

A device or appurtenance attached to a plumbing fixture or water outlet, such as a faucet, shower valve, or flushometer, that controls water flow.