WBCHSE HS Vocational Plumbing key terms

Clothing and gear worn to reduce injury risk on site, such as helmets, safety goggles, gloves, boots and dust masks. It is the last line of defence after hazards are removed or controlled.

A written authorisation issued before a hazardous task, naming the work, its location, the hazards, the controls and the person in charge. It confirms checks were done and must be closed on completion.

Entering an enclosed area such as a septic tank, manhole or underground water tank with limited openings and poor natural ventilation. It requires gas testing, a standby person, rescue arrangements and a permit before entry.

A safety procedure where an energy source such as a pump motor or valve is switched off, locked and marked with a tag so it cannot be restarted while someone works on the equipment.

A steel pipe coated with zinc to resist rust, widely used for cold water lines and sometimes for drainage. Threaded joints are common, and the coating must be protected from damage during cutting and threading.

A light, corrosion-resistant plastic pipe made of polyvinyl chloride, joined by solvent cement or rubber-ring push fittings. It is common in drainage, soil lines and cold water supply but softens at high temperature.

Chlorinated polyvinyl chloride pipe that withstands hotter water than ordinary PVC, so it is used for hot and cold domestic supply lines. It needs its own compatible cement and fittings.

A permanent plastic pipe joint made by coating both pipe end and fitting socket with cement, then pushing and twisting them together. The surfaces soften and fuse as the solvent evaporates.

Cutting a tapered screw thread on the end of a metal pipe so it can be screwed into a fitting. Correct thread length and cutting oil give a tight, leak-free joint.

An adjustable hand tool with serrated jaws that grip and turn threaded pipes and fittings. The jaws are set so that pulling the handle tightens the grip on the pipe.

A clamping device fixed to a workbench or stand that holds a pipe firmly while it is cut, threaded or filed. It frees both hands and prevents the pipe from rotating.

A hand tool with a sharp cutting wheel that scores and severs a pipe as it is rotated around it. The cut edge is usually reamed to remove the internal burr.

A tool used to remove the sharp inner burr left after cutting a pipe. Reaming restores full bore and reduces turbulence and corrosion at the cut end.

A description of pipe wrench design in which the jaws grip tighter as force is applied to the handle. It is named after the original wrench design and appears in tool specifications.

A cord with a pointed weight hung to establish a true vertical reference. Plumbers use it to check that a riser or soil pipe is standing straight.

A tool containing a liquid-filled vial with an air bubble that shows whether a surface is horizontal or vertical. It is essential for checking fixture levels and pipe falls.

The downward slope given to a drain pipe so that waste flows by gravity to the sewer. Too little slope causes silting; too much leaves solids behind while water runs ahead.

The vertical or horizontal pipe that carries sewage containing human waste from water closets to the drainage system. It is distinct from a waste pipe, which carries sullage only.

A pipe that carries sullage, that is, wastewater from sinks, basins, baths and showers, without human excreta. It connects fixtures to the drainage stack or gully.

A pipe open to atmosphere that lets air into the drainage system behind flowing waste. It protects trap seals from siphonage and allows sewer gases to escape safely above roof level.

The depth of water held in a trap that blocks sewer gas from entering a building. It is measured between the dip and the outlet crown, and is typically 50 mm in Indian practice.

A trap fitted at the outlet of a waste pipe or at a yard gully to hold a water seal and catch debris. It is accessible through a grating for cleaning.

A covered access point built into a drain run, with a removable cover and often a channel at the base, allowing rodding and inspection of the line without excavation.

A large covered chamber giving a person access to a sewer or deep drain for inspection, cleaning and repair. It usually has steps, a benched base and a heavy cover at ground level.

A sanitary fixture used for the reception and flushing of human excreta into the drainage system. It may be a squat pan or a pedestal type with a cistern or flush valve.

A tank that stores water and releases a measured flush to clear a water closet or urinal. It contains an inlet valve, a float, an overflow and a flush mechanism.

A float-operated inlet valve inside a storage tank or cistern that opens when the water level drops and shuts off when the tank is full. A faulty washer here causes continuous overflow.

A storage tank placed at roof level to supply water by gravity to outlets below. Its height above the highest fixture determines the pressure available at that fixture.

A valve with a sliding gate that opens or closes a water line fully, giving low resistance when open. It is used for isolation rather than for regulating flow.

A pocket of trapped air in a pipe that blocks or reduces water flow, often after a line has been drained and refilled. It is cleared by opening a vent or bleeding the highest outlet.

A banging noise and pressure surge caused when moving water is stopped suddenly by a fast-closing tap or valve. It can be reduced by air chambers, slow-closing valves or arrestors.

The process of locating where water escapes from a pipe or fitting, using signs such as damp patches, meter movement, sound or pressure testing. Early detection prevents structural damage and waste.

A check in which a pipe system is filled and pressurised, then watched for a drop in gauge reading. It proves joints are sound before the line is covered or put into service.

A device fitted on the service connection that measures the volume of water passing into a premises. It is used for billing and also for detecting hidden leaks by observing flow with all taps closed.

A short connecting fitting that taps water from a main or joins a small service pipe to a larger one. In municipal supply it links the communication pipe to the consumer's service pipe.

A priced schedule listing each item of work with its description, unit and quantity, prepared from measured drawings. It forms the basis for tendering and for progress payments.

The process of extracting measured quantities of pipes, fittings and fixtures from drawings and recording them item by item. Accurate take-off prevents over- or under-ordering of materials.

Working out the unit cost of an item from material, labour, tools, overheads and profit. The resulting rate is used to price the bill of quantities.

A record sheet where the length, breadth, height and number of each item of work are written as measured on site. Quantities and the bill of quantities are computed from it.