Monday, 3 August 2020, 3:42 PM
Site: Plumbers School
Course: Plumbers School (Home)
Glossary: Plumbing Dictionary
R

RELIEF OPENING

The opening provided in a draft hood to permit the ready escape to the atmosphere of the flue products from the draft hood in the event of no draft, back draft, or stoppage beyond the draft hood, and to permit air into the draft hood in the event of a strong chimney updraft.

RELIEF VALVE

Pressure relief valve. A pressure-actuated valve held closed by a spring or other means and designed to relieve pressure automatically at the pressure at which such valve is set.

RELIEF VALVE (DEVICE)

A safety valve designed to forestall the development of a dangerous condition by relieving either pressure, temperature, or vacuum in the hot water supply system.

RELIEF VALVE Temperature and pressure.

A combination relief valve designed to function as both a temperature relief and pressure relief valve.

RELIEF VALVE, PRESSURE

An automatic valve which opens and closes a relief vent, depending on whether the pressure is above or below a predetermined value.

RELIEF VALVE, TEMPERATURE

Reseating or self-closing type. An automatic valve which opens and closes a relief vent, depending on whether the temperature is above or below a predetermined value. Temperature relief valve. A temperature-actuated valve designed to discharge automatically at the temperature at which such valve is set.

RELIEF VALVE, VACUUM

An automatic valve which opens and closes a vent for relieving a vacuum within the hot water supply system depending on whether the vacuum is above or below a predetermined value.

RELIEF VENT

A vent whose primary function is to provide circulation of air between drainage and vent systems.

RETURN AIR SYSTEM

An assembly of connected ducts, plenums, fittings, registers, and grilles, through which air from the spaces to be heated or cooled is conducted back to the supply unit. (See also SUPPLY AIR SYSTEM.)

RIM

An unobstructed open edge of a fixture. RISER.  See "Water pipe, riser."

ROOF DRAIN

A drain installed to receive water collecting on the surface of a roof and to discharge such water into a leader or a conductor.

ROOM HEATER

A self-contained gas-burning appliance installed in and for heating rooms. This definition shall not include unit heaters, central heating gas appliances, garage heaters, or vented wall furnaces.

ROUGH-IN

Parts of the plumbing system that are installed prior to the installation of fixtures. This includes drainage, water supply, vent piping and the necessary fixture supports and any fixtures that are built into the structure.
S

SAFETY SHUTOFF DEVICE

A device that will shut off the gas supply to the controlled burners in the event the source of ignition fails to ignite the gas at the burners. This device may interrupt the flow of gas to the main burners only, or to the pilot and the burners under its supervision.

SECONDARY AIR

The air externally supplied to the flame at the point of combustion.

SELF-CLOSING FAUCET

A faucet containing a valve that automatically closes upon deactivation of the opening means.

SEPARATOR

See "Interceptor."

SERVICE PIPE

The pipe which brings the gas from the gas main to the point of delivery.

SET OUT

See "Final"

SEWAGE

Any liquid waste containing animal or vegetable matter in suspension or solution, including liquids containing chemicals in solution.