BTEB Plumbing key terms

Water that is safe for human drinking and cooking because it meets quality standards for harmful organisms, chemicals, and turbidity. Plumbing codes require potable water in fixtures used for drinking, food preparation, and personal washing.

A device or arrangement that stops used water from reversing into the clean supply. Common methods include air gaps, check valves, and reduced-pressure zone assemblies, chosen based on the hazard level of the connected fixture or system.

Any actual or potential link between a potable water system and a source of contamination or pollution. Even a temporary link, such as a submerged hose end, can allow backflow, so codes require protection at every such point.

The unobstructed vertical distance between the lowest opening of a water outlet and the flood rim of the receiving fixture. It is the most reliable backflow protection because no mechanical part can fail.

The top edge of a fixture or receptacle from which water would overflow onto the floor. Fixture clearances, air gaps, and overflow requirements are all measured from this reference line.

A loud banging or knocking in piping caused by a sudden change in flow velocity, such as a quickly closing valve. The pressure surge can damage joints and fittings, so arrestors or cushioning devices are installed to absorb it.

A device containing a trapped air chamber or piston that absorbs the pressure spike created when flow stops abruptly. It is placed near the fixture or valve that causes the shock.

The total measured run of pipe along its centerline, including all horizontal and vertical segments but excluding the length taken up by fittings. It is used to calculate friction loss and material quantities.

A method of expressing the pressure loss of fittings and valves as an added length of straight pipe. Adding it to the developed length gives the effective total used in sizing and pressure-loss calculations.

The drop in water pressure as fluid moves through pipe, caused by roughness, velocity, and fittings. Designers limit it so that fixtures at the farthest point still receive adequate flow and pressure.

The pressure exerted by water at rest, determined by the height of the water column above the point measured. Roughly 0.43 psi is gained per foot of rise, which matters in tall buildings.

A device that lowers incoming water pressure to a safe, usable level for the building's piping and fixtures. It protects against excessive pressure that can damage appliances and cause noisy flow or leaks.

A tank with a trapped air cushion or diaphragm that absorbs the volume increase of water heated in a closed system. Without it, thermal expansion can raise pressure until relief valves discharge or joints fail.

A safety device on water heaters that opens automatically when internal temperature or pressure exceeds set limits. It must be piped to a safe discharge point and never capped or blocked.

An appliance that heats and stores or instantly delivers hot water for fixtures and appliances. Installation requires correct relief protection, venting, clearances, and connection to the distribution piping.

A return pipe that keeps hot water moving through the system so fixtures receive hot water quickly. It reduces waiting time and wasted water, and may rely on gravity, a pump, or a thermostatic control.

A numerical value that expresses the probable discharge load a fixture places on the drainage system. Values are added to determine the required pipe size for branches, stacks, and building drains.

The drain pipe that connects one fixture or a group of fixtures to a stack or building drain. Its size is based on the total fixture units it serves and the slope of the run.

The vertical drain pipe that carries sewage from water closets and other fixtures down through the building. It must extend through the roof or connect to a venting arrangement to admit air.

A vertical pipe that provides air to the drainage system and releases sewer gases above the roof. It protects trap seals by keeping pressure in the drain piping close to atmospheric.

The depth of water held in a fixture trap that blocks sewer gas from entering the building. It is measured between the trap weir and the dip of the trap, and must be maintained by proper venting.

The section of drain pipe between a fixture trap and the point where it connects to a branch or stack. Its length and slope are limited by code so the trap does not self-siphon.

A small device or connection that adds water to a floor drain trap to replace evaporation. It keeps the trap seal intact in drains that see infrequent use, preventing sewer odors from escaping.

A drain set into the floor that receives surface water and spills for disposal into the sanitary or storm system. It includes a trap and often a strainer to catch debris.

An accessible opening fitted with a removable plug that allows a drain line to be cleared of blockages. Codes specify where cleanouts are required based on pipe length, direction changes, and location.

The downward fall of a horizontal drain pipe, usually stated in inches per foot or as a percentage. Adequate slope lets solids move with the flow while preventing water from outrunning waste.

A rigid thermoplastic pipe made of polyvinyl chloride, widely used for drainage, waste, and vent lines and for cold water where approved. It is joined with solvent cement or mechanical fittings.

Chlorinated polyvinyl chloride, a thermoplastic pipe with higher temperature resistance than standard PVC. It is commonly used for hot and cold domestic water distribution and is joined by solvent cementing.

Cross-linked polyethylene flexible tubing used for hot and cold water distribution. It bends around corners, needs fewer fittings, and is connected with crimp, clamp, or push-style fittings.

Metal pipe available in rigid and flexible forms and rated by wall thickness, such as types K, L, and M. It resists corrosion and heat, and is joined by soldering, brazing, or press fittings.

A fitting with an insulating component that separates two dissimilar metals to stop galvanic corrosion. It is typically installed where copper piping meets steel piping or a steel water heater tank.

Deterioration that occurs when two different metals contact each other in the presence of an electrolyte such as water. The less noble metal corrodes, which is why dissimilar connections need isolation.

A connection made by applying primer and cement to PVC or CPVC pipe and fitting, softening the surfaces so they fuse. Proper technique includes cleaning, full insertion, a quarter turn, and holding time.

A liquid applied to plastic pipe and fittings before solvent cement to clean and soften the surfaces. It helps the cement penetrate and produce a strong, leak-free fused joint.

A mechanical connection secured by compressing the fitting onto the pipe with a specialized tool. It is used on copper and some other systems and avoids open flame, which suits occupied buildings.

A brand-style push-to-connect fitting that grips and seals pipe when inserted, using an internal O-ring and retainer. It allows fast repairs and transitions but must match the pipe type and be accessible where required.

A distribution header with multiple outlets that supplies individual fixtures or zones from one location. In PEX systems it reduces hidden fittings and allows separate shutoff or control for each run.

A valve installed to stop water flow to a fixture, appliance, or section of piping for repair or emergency isolation. Codes require accessible shutoffs on supply lines to fixtures and at the main service.

A valve with a rotating ball that has a bore through it, giving quick quarter-turn operation and low resistance to flow. It is common for main shutoffs and branch isolation because it opens fully.

A toilet fixture that receives human waste and discharges it through a trap to the drainage system. Installation requires correct rough-in distance, water supply height, and secure floor mounting.

The stage of plumbing work where pipes, fittings, and supports are installed before walls, floors, and fixtures are finished. Correct dimensions at this stage determine whether fixtures align and connect properly.

A fitting that provides a flat surface for mounting a fixture or joining pipe ends, such as the closet flange that anchors a water closet. It must be secured and sealed to prevent leaks at the floor.

A passage built into a fixture that lets excess water drain before it spills over the flood level rim. It is common on bathtubs, sinks, and lavatories and must connect to the drainage path.

A washbasin fixture used for personal washing, supplied with hot and cold water and drained through a trap. Its drain assembly often includes a pop-up stopper and an overflow passage.

Gear worn to reduce injury risk on the job, such as safety glasses, gloves, hearing protection, and respirators. Employers must provide suitable equipment and train workers in its correct use.

A procedure for isolating energy sources and attaching warning tags before servicing equipment. It prevents accidental startup or release of stored energy while a worker is repairing or installing a system.

An area with limited entry and exit that is not designed for continuous occupancy, such as a pit or vault. Entry may require testing the atmosphere, ventilation, an attendant, and a permit.

Practices that protect workers in excavations, including sloping, shoring, and safe access. Trenches can collapse suddenly, so spoil placement, water control, and daily inspection are essential.

A material designation for piping, solder, and flux that limits lead content to protect drinking water. Older lead service lines and lead-based solder are a known health hazard and may need replacement.

A paste applied to metal surfaces before soldering to prevent oxidation and help solder flow. Excess flux must be wiped away because residues can corrode the joint and contaminate water.

The process of measuring and listing quantities of pipe, fittings, fixtures, and labor from drawings for estimating. An accurate takeoff includes waste allowances, supports, and specialty items.

An added percentage of material quantity included in an estimate to cover cutting losses, breakage, and minor errors. It varies with material type and job conditions and is added on top of calculated needs.

A written document that modifies the scope, price, or schedule of a construction contract after work begins. It protects both parties by recording approved changes before extra work is performed.