Plumbing NC II key terms

Gear worn to reduce injury risk on site, such as safety shoes, hard hat, gloves, goggles, and hearing protection. It supplements, but never replaces, safe work practices and engineering controls.

Procedure for isolating energy sources, such as electricity or pressurized water, and applying locks and tags so equipment cannot be re-energized while someone works on it.

A step-by-step review of a task that identifies hazards at each stage and states the controls to be applied before work begins, often recorded on a short written form.

Entering an enclosed area such as a septic tank, manhole, or deep pit that has limited access and may hold toxic gas or low oxygen. Requires testing, ventilation, an attendant, and a permit.

Keeping the work area clean, orderly, and free of trip and fire hazards. The 5S method sorts, sets in order, shines, standardizes, and sustains these practices on site.

A document supplied with a chemical product that lists its hazards, safe handling, first-aid measures, and storage requirements. Read it before opening solvents, adhesives, or flux.

Separating waste at the point of generation into categories such as recyclable metal and plastic, general refuse, and hazardous items, so each stream is disposed of correctly.

A drawing method that shows a three-dimensional object as separate flat views, usually plan, front elevation, and side elevation, arranged in a fixed relationship on the sheet.

The view of a layout seen from above, showing the positions of fixtures, pipes, and risers in a building. It is the main drawing used to set out plumbing work.

A drawing that shows a vertical face of a building or installation, giving heights of fixtures, pipe runs, and openings that a plan view alone cannot show.

A simplified schematic that shows how stacks, branches, and vents connect vertically through a building, without regard to true scale or horizontal distance.

The ratio between a drawn length and the real length it represents, such as 1:50. It lets a candidate convert measured drawing distances into actual site dimensions.

A line on a drawing, usually with arrowheads and a number, that states the size or position of a feature. Extension lines carry the measurement from the object to the dimension line.

A list accompanying the drawings that itemizes pipes, fittings, fixtures, and quantities required for the job, used for ordering and for checking deliveries against the design.

The height of the inside bottom of a drain pipe at a given point, measured from a fixed datum. Comparing invert levels along a run gives the fall of the drain.

The downward slope of a drain or pipe expressed as a ratio, such as 1:60, or as a percentage. Adequate fall lets waste flow by gravity without leaving solids behind.

Plumb means exactly vertical and level means exactly horizontal. Checking both keeps risers straight, pipe runs true, and fixtures sitting evenly on their supports.

A tool with sealed vials of liquid and an air bubble that shows whether a surface is horizontal or vertical. Longer levels give more reliable readings over pipe runs.

A pointed weight hung on a cord to establish a true vertical line. It is used to transfer points from floor to ceiling, for example when setting out a soil stack.

A marked reference line running along the middle of a proposed pipe run or wall, from which equal distances are measured to set out both sides of the work.

The standard size label used to identify pipe, such as NPS 1/2 or NPS 2. For many sizes it is close to, but not exactly, the actual outside diameter.

A number, such as Schedule 40 or Schedule 80, that indicates the wall thickness of a pipe for a given nominal size. Higher schedules give thicker walls and higher pressure ratings.

The length of pipe thread or socket depth that a fitting consumes when assembled. It must be subtracted from measured center-to-center distances when cutting pipe.

A tapered spiral cut on the end of a pipe that lets it screw into a matching fitting. Standard pipe threads taper so the joint tightens and seals as it is turned.

A hand tool that scores and cuts pipe by rotating a sharp wheel around it while tightening progressively. The cut end must be reamed to remove the internal burr.

A tool that removes the raised metal burr left inside a cut pipe end. Reaming restores full bore and reduces turbulence and corrosion at the joint.

A cutting tool with hardened steel teeth that forms external threads on a pipe when turned around it, usually held in a stock and lubricated with cutting oil.

An adjustable wrench with serrated jaws that grip round pipe for turning or holding. The jaws bite in one direction, so orient the wrench correctly to avoid slipping.

A permanent joint for plastic pipe made by applying solvent cement, which softens both surfaces and fuses them. Surfaces must be cleaned and primed, then held still while setting.

A physical separation between a water outlet and the highest possible level of a fixture's overflow or receptacle, preventing contaminated water from being drawn back into the supply.

Any actual or potential link between a potable water supply and a source of contamination. It must be eliminated or protected by an air gap or backflow device.

A device, such as a check valve assembly or reduced-pressure zone valve, that stops water from flowing backwards into the clean supply when pressure drops or reverses.

A banging noise and pressure surge caused when flowing water is stopped suddenly. It is reduced by correctly sized pipe, slow-closing valves, and air chambers or arrestors.

The network of pipes that carries sewage and grey water away by gravity and admits air behind the flow so traps stay sealed. It has drain, waste, and vent components.

A U-shaped fitting that holds a water seal to block sewer gas from entering the building. It must be vented and self-cleaning to keep the seal intact.

The extension of a soil or waste stack above the highest branch, which admits air to the drainage system and releases gases safely above the roof.

A unit that expresses the probable load a fixture places on the drainage or water supply system, used to size pipes and vents according to plumbing codes.

A check that pipework and joints hold pressure without leaking, done by filling or pressurizing the system and observing gauges over a set period before closing up walls.

A systematic method of finding the cause of a fault by gathering symptoms, forming likely causes, testing them one at a time, and confirming the repair works.