NV Journeyman Plumber key terms

A physical unobstructed vertical separation between a potable water outlet and the flood level rim of the receiving fixture or receptacle. It is the highest level of backflow protection and cannot be bypassed by valve failure.

An approved assembly or method that stops reversal of water flow in a potable system, such as a reduced pressure principle assembly, double check valve, or vacuum breaker. Selection depends on hazard level and degree of protection required.

Any actual or potential link between a potable water supply and a source of contamination or pollution. It becomes dangerous whenever a pressure differential or backsiphonage condition allows nonpotable fluid to enter the drinking water piping.

A testable backflow preventer with two independently acting check valves and a hydraulically operated differential relief valve between them. It protects against both backsiphonage and backpressure and suits high-hazard connections.

A device that admits air into piping to break a vacuum and prevent backsiphonage. Pressure-type units may be used on hose bibb outlets with proper installation height, while atmospheric units serve specific appliance connections.

The edge of the receptacle from which water overflows, measured at its lowest point. It establishes the reference elevation for air gaps, vacuum breaker installation height, and the top of a fixture drain or standpipe.

A dimensionless measure expressing the probable peak drainage load or water demand of a plumbing fixture relative to a fixed reference. Values are totaled to size drains, vents, water pipes, and building sewers.

The load value assigned to a fixture based on its drain size and typical use, used to size the drainage system. One unit is approximately the discharge of a lavatory, and total loads determine pipe sizing.

A value representing the probable water demand of a fixture, used to size supply piping. Values account for flow rate, frequency of use, and the diversity factor that reduces total simultaneous demand.

The vertical depth of water held in a trap that blocks sewer gas from entering a building. It is measured from the trap weir to the dip, and must be maintained against evaporation and siphonage.

The top edge of the outlet side of a trap through which water must flow before draining away. Its elevation sets the maximum seal depth and is the point from which vent distances are measured.

A vertical pipe that provides air to the drainage system and vents sewer gases to the outdoors. It extends full size from the building drain to a point above the roof and may serve as a soil or waste stack vent.

The extension of a soil or waste stack above the highest fixture connection, terminating outdoors. It relieves pressure in the stack and counts as the vent for fixtures draining into that stack.

A vent that connects to two or more fixture drains, usually at the upstream end of a branch, and relieves pressure across a group of fixtures sharing a horizontal branch. It requires a relief vent in most configurations.

A trap whose outlet turns downward immediately after the seal, creating a self-siphoning condition. It is prohibited in plumbing codes because the falling water can pull the seal out after each use.

A trap shaped so the outlet runs horizontally after the seal before turning down, preventing self-siphoning. It is the standard trap for most fixtures and must be installed level and accessible for cleaning.

The lowest horizontal portion of the drainage piping inside a building that receives soil and waste from stacks and branches. It ends at the building wall where it becomes the building sewer.

The horizontal pipe carrying sewage from the building drain to the public sewer or private disposal system. It begins outside the building wall and is sized from the total drainage fixture unit load.

An accessible fitting with a removable plug or cover that allows a drain line to be rodded or inspected. Codes require them at the base of stacks, at changes in direction, and at intervals along horizontal runs.

The total measured length of pipe plus the equivalent length added for fittings and valves. It is used to size water supply piping because pressure loss depends on both straight run and fitting resistance.

A device that lowers incoming water pressure to a safe, usable level for the building distribution system. It protects fixtures and appliances from excessive pressure and may require a thermal expansion tank downstream.

The increase in water volume as it is heated, which raises pressure in a closed plumbing system. A thermal expansion tank or equivalent control prevents relief valve discharge and pipe stress.

A device containing a trapped air chamber or piston that absorbs the shock wave when a valve closes quickly. It is installed near quick-closing valves to prevent pipe noise and damage.

A safety valve that opens when tank temperature or pressure exceeds set limits, discharging hot water to a safe location. Its discharge pipe must be full size, gravity-drained, and terminate where scalding is not a hazard.

An appliance that heats and stores potable water for domestic use, typically with a tank, thermostat, and relief valve. Installation requires a drain pan, seismic strapping where required, and proper venting for fuel-fired units.

The passage that carries combustion products from a fuel-burning appliance to the outdoors. It must be sized, sloped, and connected to an approved venting system to prevent spillage of carbon monoxide.

The system of pipe, tubing, and fittings that delivers fuel gas from the meter or service regulator to appliances. Sizing depends on load, length, pressure, and allowable pressure drop.

A vertical pipe section at the bottom of a gas line that collects dirt, scale, and condensate before gas reaches the appliance controls. Also called a sediment trap, it must be installed at each appliance connection.

A valve installed on a supply pipe to isolate a fixture, appliance, or building section for repair. It must be accessible and listed for the application, and gas shutoffs must be clearly identified.

A valve, often a compression or quarter-turn type, that controls water flow to a single fixture or branch. It allows servicing without draining the entire system and must remain accessible.

The pipe that connects one fixture or a group of fixtures to a soil, waste, or supply main. Its size is based on fixture units and the number of fixtures served.

A vertical pipe that carries the discharge of water closets and may also receive other fixtures. It extends through the roof as a vent and must be sized to handle the total fixture unit load.

A vertical pipe that receives discharge from fixtures or appliances and connects to a drain, or a pipe system for fire hose connections. In drainage use it must be trapped and vented properly.

A device that separates and retains grease, oil, sand, or other harmful substances from wastewater before it enters the drainage system. It requires regular maintenance and must be properly vented.

A type of interceptor that slows wastewater flow so fats, oils, and grease float and are retained for removal. It must be sized to the fixture load and kept accessible for cleaning.

A three-dimensional scale drawing showing piping runs at 30-degree angles on a flat sheet. Plumbers use it to plan layouts, calculate fitting counts, and verify elevations before installation.

A quantified list of pipe, fittings, valves, and fixtures derived from plans and specifications. It drives purchasing, labor estimates, and permit documentation for a plumbing project.

Written authorization from the authority having jurisdiction to perform regulated plumbing work. It triggers inspections, establishes scope, and must be obtained before work begins except for listed exemptions.

An official examination of plumbing work at defined stages, such as rough-in, top-out, and final. Approval at each stage is required before concealing piping or placing systems in service.

The stage of installation when piping, fittings, and supports are in place but fixtures and finishes are not yet installed. It must be inspected and approved before walls or slabs are closed.

The organization, office, or individual responsible for enforcing code requirements and approving installations, materials, and procedures. In Nevada this is typically the local building department or state agency with delegated authority.

The official evaluation of submitted drawings and specifications for code compliance before a permit is issued. It verifies fixture counts, pipe sizing, venting, and life-safety requirements.

The state agency that licenses and regulates contractors, including plumbing contractors, in Nevada. It administers classifications, exams, bonding, and disciplinary actions for licensed contracting work.

A credential authorizing an individual to perform plumbing work under a licensed contractor in Nevada. It requires documented experience, passage of an examination, and compliance with continuing education and renewal rules.

A structured training program combining paid on-the-job hours with related classroom instruction. In plumbing it is the typical pathway to journeyman status and requires documented hour accumulation and employer sponsorship.

A document provided by manufacturers that lists hazards, handling, and emergency procedures for a chemical product. It must be accessible to workers on jobsites where hazardous materials are stored or used.

A space large enough to enter, with limited entry or exit, not designed for continuous occupancy, such as a vault or trench. Entry requires hazard evaluation, atmospheric testing, and attendant procedures.

Gear worn to reduce workplace injury, including safety glasses, gloves, hard hats, respirators, and hearing protection. Employers must provide it, train workers, and enforce its use where hazards exist.

A system of supports, sloping, or shielding that protects workers from cave-ins in excavations. It is required when trenches reach depths set by safety rules and when soil conditions create collapse hazards.