OK Plumber key terms

Official approval issued by the local building department that allows plumbing work to begin. It triggers required inspections and confirms the job will be reviewed against the adopted code.

The inspection performed after piping is installed but before walls, floors, or fixtures conceal it, letting the inspector verify pipe size, slope, support, and venting while everything is still visible.

The official or agency that enforces the plumbing code in a given area. This office issues permits, performs inspections, and settles questions about how code requirements apply to a specific job.

The highest level of plumbing credential in most states. It lets the holder contract for plumbing work, pull permits, and supervise journeymen and apprentices on the job.

Written permission from the code authority to use an alternative method or material that does not strictly meet the code but gives equivalent safety and performance. It is granted case by case.

The unwanted reverse flow of used or contaminated water into a potable water system, usually caused by backsiphonage or backpressure. Preventing it protects drinking water from pollution and contamination.

The unobstructed vertical space between the lowest point of a water outlet and the flood level rim of the fixture it serves. It is the most reliable form of backflow protection.

Any actual or potential link between a potable water supply and a source of contamination or pollution. Each one must be protected by an air gap or an approved backflow prevention assembly.

A device that lowers incoming water pressure to a safe, steady level for the building's piping and fixtures. It is typically set between 50 and 75 psi and often includes a strainer.

A small air chamber or piston device installed near a quick-closing valve to absorb the shock wave created when water flow stops suddenly, preventing banging pipes and pressure spikes.

A number that rates the probable demand a fixture places on the water distribution system. Code tables use these values to size supply pipes, meters, and main lines.

A tank with a pressurized air bladder installed on a closed water system to absorb the volume increase as water heats, protecting pipes and the water heater from excess pressure.

A U-shaped fitting that holds a water seal blocking sewer gas from entering a building while letting wastewater pass through. Nearly every fixture must have one.

The section of pipe between a trap's outlet weir and the point where it connects to a vented drain. Code limits its length to keep the trap seal from being siphoned away.

The depth of water held in the dip of a trap that blocks sewer gas. It is commonly 2 to 4 inches deep and can be lost through evaporation, siphonage, or backpressure.

A vertical pipe that supplies air to the drainage system and carries sewer gases to the outdoors. It protects trap seals from being pulled out by siphonage.

The extension of a soil or waste stack above the highest branch connection. It runs through the roof to admit air and release sewer gases.

A one-way valve that lets air into a drain line to protect trap seals but does not allow sewer gas to escape. Code permits it in place of some vents.

An accessible fitting with a removable plug that gives direct access to a drain or sewer for clearing stoppages. Code requires them at the building drain end and at set intervals.

The lowest pipe inside a building that receives soil and waste from stacks and carries it to the building sewer. It typically ends about 30 inches outside the foundation wall.

A number expressing the rate at which a fixture discharges waste into the drainage system. Code tables use these values to size drains, branches, and stacks.

The downward pitch of a horizontal drain, stated in inches per foot, that lets wastewater flow by gravity while carrying solids along. Small pipe commonly uses one-quarter inch per foot.

A flap device installed on a drain to stop sewage from a surging or flooded public sewer from flowing backward into a building. It must be accessible for service.

A receptacle that receives water or waste and discharges it into the drainage system, such as a sink, water closet, tub, or floor drain.

The top edge of a fixture basin where water would spill onto the floor. It sets the reference height for air gaps, vacuum breakers, and vent connections.

A device attached to a fixture that delivers or controls water, such as a faucet, flushometer valve, supply stop, or mixing valve.

A toilet fixture that receives human waste and flushes it into the drainage system using either a gravity tank or a flushometer valve.

A valve that uses line pressure to deliver a measured flush to a water closet or urinal. It needs adequate pressure and flow at the fixture to work correctly.

The ring that anchors a water closet to the floor and connects its outlet to the drain pipe, usually sealed with a wax ring or gasket to prevent leaks.

A mixing valve that blends hot and cold water to deliver a limited, safe temperature to fixtures. It helps prevent scalding at sinks, tubs, and hand-washing stations.

A safety device on a water heater that opens to release excess temperature or pressure, preventing a tank rupture. Its discharge pipe must terminate in a safe, approved location.

A vertical pipe that receives discharge from an appliance such as a clothes washer, with a trap below it. It is sized so the hose fits loosely and its rim sits at a required height.

A short vertical drop with a capped nipple installed at the bottom of a gas line near an appliance. It catches dirt and condensation before they reach the burner controls.

A device that reduces incoming gas pressure to a steady delivery pressure the appliance needs. Regulators may be located at the meter, on the service, or at the appliance.

Flexible stainless steel tubing with a protective jacket used for gas piping. It must be bonded to the electrical grounding system, protected from damage, and installed per the manufacturer's instructions.

A pressure test of gas piping using air or inert gas and a gauge, held for a set period to prove the joints are tight before gas is turned on.

Air supplied to gas appliances for burning fuel and for diluting and venting flue gases. An inadequate supply causes incomplete combustion and carbon monoxide hazards.

A space large enough to enter that has limited entry or exit and is not meant for continuous occupancy, such as a pit or vault. Entry requires testing, a permit, and an attendant.

Shoring, shielding, or sloping used to prevent cave-ins in excavations. It is required for trenches five feet deep or more, with a competent person inspecting the site daily.

A procedure that isolates energy sources and locks or tags them so equipment cannot be started while a worker is servicing it. Only the person who applied the lock removes it.

Gear such as safety glasses, gloves, hard hats, and respirators worn to reduce the risk of injury on the job. Employers must provide it and train workers on proper use.