Cert III Plumbing flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hierarchy of control

The ranked order for managing risk: eliminate, substitute, isolate, engineer, administer, then PPE. Higher controls are more reliable and must be considered first.

Dangerous incident notification

A serious near miss such as a collapse, electrical contact or gas leak must be reported to the WHS regulator immediately by phone, with written notice within 48 hours.

Confined space entry

Entry requires a permit, gas testing for oxygen and contaminants, a standby person outside, continuous communication, and a rescue plan before anyone enters.

Waste hierarchy

The preferred order for managing waste: avoid, reduce, reuse, recycle, recover energy, then dispose. Plumbers apply it to offcuts, packaging, spoil and wash water.

Silt fence purpose

A sediment control barrier placed downslope of disturbed ground to trap soil before runoff reaches stormwater. It is inspected after rain and removed only after stabilisation.

Backflow prevention device

A testable fitting such as a reduced pressure zone device that stops contaminated water reversing into potable supply. It is tested annually by an accredited tester.

Pipe volume formula

Volume equals pi times radius squared times length. A 100 mm diameter pipe holds about 7.85 litres per metre, useful for test water and dosing calculations.

Calculating drain fall

Fall in millimetres equals pipe length in millimetres divided by the gradient ratio. A 1 in 60 fall over 12 metres gives 200 mm of fall.

BSP thread

The British Standard Pipe thread used on Australian plumbing fittings. A 15 mm (half inch) size has about 14 threads per inch and seals with tape or paste.

PN and SN pipe ratings

PN is the pressure rating of pressure pipe (PN12, PN15). SN is the stiffness rating of non-pressure sewer pipe (SN4, SN8) used for buried drainage.

Height of instrument

The reduced level of a known benchmark plus the backsight reading on that point. Subtracting a foresight from it gives the level of a new point.

Invert level

The level of the lowest inside surface of a pipe or pit. Cover level minus invert level gives the depth of the pipe below the surface.

Fixture unit method

A sizing method where each fixture is given a discharge unit value; the total load determines the required drain and vent diameters.

Trap seal depth

The water depth in a fixture trap that stops sewer gas entering the building. It is normally 25 to 50 mm and must be protected by a vent.

Drainage water test

The pipe section is sealed, filled with water to the highest point and held for at least 15 minutes to prove the joints are watertight before backfilling.

Static pressure from head

Pressure in kilopascals equals about 10 times the height of water in metres. A tank 10 metres above a fixture delivers roughly 100 kPa static pressure.

Roof catchment flow

Rainfall intensity in millimetres per hour multiplied by roof area in square metres gives litres per hour; divide by 3600 to convert to litres per second.

First flush diverter

A device that discards the first rainwater off a roof, which carries dust and bird droppings, before the cleaner water enters the storage tank.

LP gas density

Liquefied petroleum gas is heavier than air, with a specific gravity of about 1.5 to 2.0, so leaks settle in pits, trenches and low areas.

Gas leakage test

New gas pipework is pressure-tested with air or inert gas, usually at 1.5 times maximum operating pressure, and must hold with no pressure drop.

Gas pipe joint restriction

Gas pipe joints must be accessible for testing and repair. Concealed joints in wall cavities, slabs or inaccessible ducts are not permitted.

Sensible versus latent heat

Sensible heat changes a substance's temperature; latent heat changes its state without a temperature change, such as boiling water into steam.

Vapour compression cycle

The compressor raises refrigerant pressure and temperature, the condenser rejects heat, the expansion device drops pressure, and the evaporator absorbs heat.

Refrigerant recovery

Refrigerant must be recovered into approved cylinders and never vented to atmosphere. Handling requires a refrigerant licence and correct cylinder identification.

Trench shoring requirement

A trench 1.5 metres or deeper requires shoring, benching or a shield, and a competent person inspects it daily and after rain before work resumes.

Dial before you dig

A free service that supplies plans of underground assets before excavation. Plans must be confirmed by potholing near live services.

Pipe bedding

A prepared granular layer under and around a buried pipe that spreads load and protects the pipe. It is compacted before the pipe is laid to grade.

Brazing temperature

Brazing uses filler metal and occurs above 450 degrees Celsius, while soldering occurs below that temperature. Capillary action fills the joint.

Flashback arrestor

A safety device fitted to oxy-acetylene regulators and torches that stops a flame travelling back into the hose or cylinder.

Solvent cement jointing

PVC joints are made by cleaning, applying solvent cement to both surfaces, pushing fully home, holding briefly and wiping the bead before curing.

Active listening

A communication technique using paraphrasing, open questions and summarising to confirm the customer's meaning and reduce misunderstandings and callbacks.

Variation record

A written, signed record of a change to the agreed scope, price or program. It protects both parties and supports later claims and invoicing.