LA Plumber key terms

A model plumbing code adopted by many jurisdictions as the basis for local plumbing regulation. It sets minimum standards for design, materials, installation, and inspection of plumbing systems.

The official, agency, or individual responsible for enforcing a code and approving materials, installations, and interpretations. The AHJ conducts inspections and may grant variances where the code allows.

A written authorization from the AHJ allowing specified plumbing work to proceed. Work covered by a permit requires inspection and approval before the system may be placed in service.

The stage of construction when piping, fittings, and supports are installed but fixtures and final connections are not yet set. Rough-in inspection must pass before walls or slabs are closed.

An official review of plumbing work by the AHJ at defined stages, such as rough-in, water supply testing, and final. Approval confirms the work meets code before it is covered or placed in service.

A dimensionless measure of the probable load a fixture places on the drainage or water supply system. One fixture unit approximates the discharge of a lavatory; larger fixtures carry higher values.

The fixture-unit value assigned to a fixture for sizing the drainage system, based on its discharge rate and usage. DFU values are summed to determine pipe sizes and drain capacity.

The fixture-unit value used to size water supply piping, reflecting a fixture's flow demand and diversity of use. Total WSFU is converted to probable demand in gallons per minute.

The estimated peak water flow, usually in gallons per minute, that a building's fixtures will require simultaneously. It is derived from total water supply fixture units and used to size the water service and mains.

The total equivalent pipe length of a water supply run, including straight pipe plus allowances for fittings and valves. It is used with probable demand to select pipe size from sizing tables.

The downward pitch of horizontal drainage pipe, expressed as fall per unit of run, such as one-quarter inch per foot. Adequate slope carries solids while maintaining self-cleansing velocity.

The pipe and fittings that convey potable water from the water main or source to the building, ending at the first shutoff valve or meter. It must be sized for probable demand and protected from contamination.

A pressure test in which a water supply system is filled with water and pressurized above working pressure for a set period to reveal leaks. It must be witnessed or documented for inspection approval.

A pressure test using compressed air instead of water, permitted in some circumstances for DWV or water piping. The test pressure and duration are specified by code and must be monitored with a gauge.

A pressure surge caused by sudden stoppage of water flow, producing banging and potential pipe damage. It is controlled with air chambers, arrestors, or properly sized and supported piping.

A device containing a trapped air cushion or mechanical element that absorbs pressure surges in water piping. It is installed near quick-closing valves such as flushometers or solenoid valves.

The combined drain, waste, and vent piping that removes sewage and wastewater while admitting air to protect trap seals. Drainage piping slopes to a building drain; vents equalize pressure.

A vertical vent pipe that extends from the drainage system to outdoor air, providing pressure relief for fixtures on multiple floors. It may serve as a soil or waste stack vent where code permits.

The water held in a fixture trap that blocks sewer gas from entering the building. Its depth is code-specified, and it must be protected from siphonage by proper venting.

The section of drain pipe between a fixture trap and the branch or stack it connects to. Its length and slope are limited by code to preserve the trap seal and allow proper drainage.

The lowest horizontal drainage pipe inside the building that receives soil and waste from stacks and branches. It connects to the building sewer at or outside the foundation wall.

The pipe carrying sewage from the building drain to the public sewer or private disposal system. It is sized by drainage fixture units and must maintain required slope.

An accessible fitting with a removable cap that allows the drainage system to be rodded or inspected. Cleanouts are required at specified intervals, at changes in direction, and at the building sewer.

The system that collects and conveys rainwater, groundwater, and surface runoff from roofs, yards, and foundations. It must be kept separate from sanitary drainage unless combined systems are approved.

A one-way valve installed on a drainage line to prevent sewage from reversing into a building during main surcharge. It must be accessible for inspection and maintenance.

A pump installed in a sump pit to remove accumulated groundwater or stormwater from a building. Discharge must be routed to an approved location and may not create a cross-connection.

The unintended reverse flow of water or other fluids into the potable supply. It occurs by backpressure or backsiphonage and is prevented by approved assemblies, devices, or air gaps.

An approved assembly or device that stops reverse flow into the potable water system. Selection depends on the degree of hazard and whether backpressure or backsiphonage is possible.

A physical separation between a potable water outlet and the flood-level rim of a receiving fixture or vessel. It is the most reliable form of backflow protection and requires no moving parts.

Any actual or potential link between the potable water system and a source of contamination or pollution. Cross-connections must be eliminated or protected by an approved backflow assembly.

An appliance that heats and stores potable water for domestic use. It requires a temperature and pressure relief valve, a discharge pipe, and proper venting or combustion air where fuel-fired.

A safety device on a water heater that opens if temperature or pressure exceeds set limits. Its discharge must terminate safely and may not be capped, trapped, or reduced in size.

A vessel that absorbs the volume increase of water as it is heated in a closed system. It protects piping and the water heater from excess pressure and prevents relief valve discharge.

The piping system that delivers natural gas or propane from the meter or tank to appliances. It is sized for pressure drop and must be tested, bonded, and installed with approved materials.

A dirt-leg fitting installed on a gas line near an appliance to catch debris before it reaches the controls. It is required by code and must be installed in the flow direction specified.

Safety gear such as eye protection, gloves, hearing protection, and respirators worn to reduce injury risk. It is required for tasks like soldering, cutting, and working with chemicals.

A space with limited entry and exit that is not designed for continuous occupancy, such as a pit or vault. Entry may require atmospheric testing, a permit, and an attendant.

Keeping work areas clean, organized, and free of hazards such as spills, scrap, and blocked exits. Good housekeeping prevents slips, trips, and fires and is required on every site.