NSW Plumbing Licence flashcards

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

Minimum drainage grade

Sanitary drainage pipes must fall at least 1:60 for DN100 and smaller, and 1:100 for DN150 and larger, to maintain self-cleansing velocity of about 0.6 m/s.

Water seal depth

A trap must retain a water seal between 25 mm and 55 mm deep; deeper seals are hard to clear and shallower seals evaporate or siphon away.

Drainage air test

A completed drainage system is air tested at 35 kPa for at least 5 minutes with no measurable drop, after all joints are sealed and the test plug installed.

Backflow hazard rating

Backflow risk is classed individual (low, single dwelling), zone (medium, multiple premises), or containment (high, boundary protection), and the device type must match the class.

Gas pipe longest-run sizing

Pipe diameter is chosen by adding the measured pipe length to an allowance for each fitting, then reading the total equivalent length against the appliance load in MJ/h.

Natural gas pressure test

A new natural gas installation is tested at 7 kPa for at least 10 minutes; any drop indicates a leak and the test must be repeated after repair.

Combustion air openings

Indoor gas appliances need two permanent openings sized at 1/1000 of the appliance input in MJ/h when ducted directly to outside air.

Roof catchment area

Catchment area in square metres equals the horizontal plan projection of the roof, obtained by multiplying plan length by plan width, not the sloping surface area.

Box gutter proportions

A high-front box gutter must have depth no greater than one third of its width, with a minimum width of 200 mm and minimum depth of 75 mm.

Minimum metal roof slopes

Corrugated metal sheet needs a minimum 5 degree slope; lapped sheet 3 degrees; metal tray 1 degree with continuous support beneath every pan.

Design rainfall intensity

Rainfall intensity for roof drainage design is taken from AS/NZS 3500.3 tables for the site, using the 5-minute, 100-year average recurrence interval value.

Overflow weir sizing

The overflow weir or rainhead must pass the full design flow at design rainfall intensity when the primary outlet is blocked, preventing ponding above the gutter.

Flashing lap minimums

Flashing must lap the roof covering by at least 150 mm, side laps at least 100 mm, and fixings must stay at least 75 mm from any lap edge.

Downpipe flow capacity

A charged DN90 downpipe carries roughly 380 L/min at 1.5 m head; always confirm capacity from the manufacturer's flow chart for the specific system.

Medical gas colour codes

Oxygen is white, nitrous oxide blue, medical air black and white, nitrogen black, carbon dioxide grey, and vacuum yellow for pipeline identification.

Medical gas pressure test

Medical gas pipelines are tested with oil-free dry nitrogen at 1.5 times design working pressure for at least 24 hours with no pressure loss recorded.

Oxygen purity limit

Medical oxygen must be at least 99.5 percent pure by volume, and medical air must have a dew point below minus 46 degrees Celsius.

Theatre air change rate

Operating theatres require 20 to 25 air changes per hour with a positive pressure differential of at least 15 Pa relative to adjacent spaces.

Duct leakage classes

Ductwork is pressure tested at 1.25 times design working pressure and classed A (low), B (medium), or C (high) according to measured leakage rate.

Medical gas alarm locations

Alarms must be fitted at the gas source, at the area alarm panel serving the clinical area, and at the master alarm in a continuously staffed location.

Terminal unit flow rates

Oxygen and medical air outlets deliver 60 to 80 L/min at 400 kPa, while vacuum outlets deliver 40 to 80 L/min at 40 kPa below atmospheric.

Pipeline identity test

After any alteration, each medical gas outlet is purged and tested for correct gas identity before the system is commissioned for clinical use.

Electrical licence boundary

Fixed electrical work requires an electrician's licence; a plumber may only disconnect and reconnect equipment within the scope permitted by their licence and state regulation.

Plug and socket reconnection

A plumber may disconnect and reconnect a fixed appliance where it connects by plug and socket; hard-wired connection needs a restricted electrical licence or an electrician.

Insulation resistance minimum

Before reconnection, insulation resistance must be at least 1 megohm when tested at 500 volts DC between active, neutral, and earth conductors.

Isolation and prove dead

Isolate at the main switch or breaker, lock and tag, then prove dead with an approved voltage tester before touching any conductor or terminal.

RCD sensitivity

A residual current device with 30 mA sensitivity must protect socket outlets and lighting circuits in domestic installations to reduce electric shock risk.

Cable derating factors

Cable current capacity is reduced for ambient temperature, grouping with other cables, and installation method; the protective device rating must not exceed the derated capacity.

Main earthing conductor

For a domestic installation with 100 A consumer mains, the main earthing conductor is at least 6 mm2 copper, checked against the AS/NZS 3000 table.

Test and tag requirement

After reconnection, portable appliances are tested and tagged, and notifiable fixed electrical work requires a certificate of electrical safety.

Earth continuity check

Before reconnection, confirm earth continuity from the appliance frame to the earthing terminal and verify active and neutral polarity at the connection point.