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Reference · 25 terms Words explained · 25 entries

Glossary. Words explained.

Standards, materials, abbreviations, and trade terms used across the VWA catalogue. Plain English, no jargon. Plumbing words, codes, materials, and short forms used on this site. Each one explained in plain English.

Standards & codes Standards and approval codes

The certifications and standards Australian plumbing work must meet. Look for these on the product spec sheet or stamped on the part. These are the approval marks and standards that plumbing products must meet in Australia. Look for them on the product page or printed on the part itself.

WaterMark Plumbing approval scheme

WaterMark is the official certification mark for plumbing products sold in Australia. It shows the product has been tested by an approved body and meets Australian plumbing safety standards. It is required by the National Plumbing Code for any product carrying water in a building.

See WaterMark products →

AS/NZS 4020 Drinking water contact standard

An Australian and New Zealand standard that tests whether plumbing products are safe to be in contact with drinking water. The standard checks that the materials do not release harmful chemicals or affect the taste of the water. Required for any product on a potable water line.

See AS/NZS 4020 products →

AS 2345 DZR brass standard

The Australian standard that defines what counts as dezincification-resistant brass. Products sold as DR brass or DZR brass in Australia must meet this standard and carry the DZR stamp on the body.

TMV3 Hospital-grade thermostatic mixing

The highest performance grade for thermostatic mixing valves. TMV3-rated valves are required in hospitals, aged care, and any setting where users cannot react quickly to temperature changes. They cut off hot water within seconds if the cold supply fails.

See TMV3 valves →

National Plumbing Code PCA · Plumbing Code of Australia

The legal rulebook for plumbing work across Australia. It sets out which products are required, how they must be installed, and which certifications they need. Often referenced just as "the Code" or "PCA". Updated periodically by the Australian Building Codes Board.

Materials Materials valves are made of

Common body materials and what they're used for. Material choice depends on water type, pressure, and service environment. The materials that valves are made from. The right material depends on the type of water, the pressure, and where the valve will be used.

DR brass DZR brass · Dezincification-resistant brass

A brass alloy with a small amount of arsenic added. The arsenic stops a kind of corrosion called dezincification, where the zinc slowly dissolves out of the brass and leaves only the porous copper behind. Required for outdoor work, underground pipes, and rainwater or bore-water systems. Costs about 15 to 25 percent more than standard brass.

See DR brass products →

CW602N European DR brass alloy code

The European code for dezincification-resistant brass. It refers to the same alloy that is sold in Australia as DR brass or DZR brass. You will see CW602N stamped on imported parts from European manufacturers.

Stainless 316 Marine-grade stainless

A grade of stainless steel that contains molybdenum, which makes it resistant to chloride corrosion. It works well in salt water, coastal air, and chemical environments where standard stainless would corrode. Used in food processing, marine, and chemical industries.

See Stainless 316 products →

PVC-U Rigid PVC · Unplasticised PVC

Rigid plastic used for cold-water and chemical-resistant pipework. Unlike flexible PVC, it does not contain plasticisers, so it stays hard and dimensionally stable. Limited to cold-water use because it softens at high temperatures. Cheaper and lighter than metal valves.

See PVC-U products →

Standard brass Yellow brass · CuZn40Pb2

Common brass made of about 60 percent copper and 40 percent zinc. Strong and easy to machine, but can suffer dezincification in aggressive water. Fine for indoor town-water plumbing. Not recommended for outdoor, underground, rainwater, or bore-water work — use DR brass instead.

Specifications Sizes and pressure measurements

How sizes, pressures, and threads are measured and labelled. These appear in every product specification. How sizes, pressure, and threads are measured and labelled. You will see these on every product page.

BSP British Standard Pipe thread

The thread standard used on most plumbing fittings in Australia. BSP threads come in two types: parallel (BSPP) for sealing with washers or O-rings, and tapered (BSPT) for sealing with thread tape or paste. The thread size names a nominal pipe bore (½", ¾", 1") rather than the actual outside diameter of the thread.

NPT National Pipe Taper · American thread

The American pipe-thread standard. NPT threads are tapered and seal by the threads compressing against each other (with thread tape). They look similar to BSP threads but the thread angle is different — they are not interchangeable with BSP. Found on imported American equipment.

½" BSP, ¾" BSP, etc Nominal pipe size

The labelled size of a BSP thread refers to the nominal bore (inner diameter) of the pipe it fits. The actual thread diameter is larger. A ½" BSP thread is about 21mm across the outside, not 12.7mm. Always specify by the label, not by the measurement.

WP Working pressure

The maximum pressure a valve is designed to handle continuously in normal service. A valve rated "20 bar WP" can run at up to 20 bar of pressure all day, every day. The actual burst pressure is much higher, but working pressure is the figure to design around.

bar Pressure unit

A pressure unit that is roughly equal to atmospheric pressure at sea level (1 bar = 100 kilopascals = about 14.5 psi). Most plumbing valves are rated 16, 20, 25, or 40 bar working pressure. High-pressure (HP) valves go up to 63 bar or higher.

kPa Kilopascal · pressure unit

The metric unit of pressure used by Australian water authorities. Domestic water supply is usually around 350 to 500 kPa. To convert: 100 kPa = 1 bar. Pressure-reducing valves are often labelled in kPa for the outlet pressure (e.g., 350 kPa PRV).

Components Types of valves

Common valve types and what each one does. Most installations combine several types in series. The main types of valves and what they each do. Most plumbing systems use several different types together.

PRV Pressure-reducing valve

A valve that lowers high incoming water pressure to a controlled outlet pressure, then keeps it steady. Mains water often arrives at 600 to 900 kPa; most fittings and appliances are rated for 350 to 500 kPa. The PRV protects everything downstream from over-pressure damage.

See pressure-reducing valves →

TMV Thermostatic mixing valve

A valve that blends hot and cold water to a fixed safe temperature, usually 38 to 50 degrees. If the cold supply fails, the TMV cuts the hot to prevent scalding. Required by code on most public-facing taps and showers. The TMV3 grade is required for hospital and aged-care work.

See thermostatic mixing valves →

Ball valve Quarter-turn isolator

A valve that uses a ball with a hole through it as the closing element. Quarter-turn of the handle rotates the ball from open (hole aligned with the pipe) to closed (hole crosswise). Fast to operate, full-bore models cause minimal flow restriction. The most common isolation valve in modern plumbing.

See ball valves →

Check valve Non-return valve · NRV

A valve that lets water flow in one direction only and blocks reverse flow. Used to stop contaminated water from siphoning back into the supply (backflow prevention) and to stop pumps from spinning backwards when they switch off.

See check valves →

Solenoid valve Electric water valve

A valve that opens and closes by electrical signal. An electromagnet pulls a small piston to open the valve when power is applied. Used in irrigation timers, dishwashers, washing machines, and any system that needs water control by computer or timer. Available as normally-open or normally-closed.

See solenoid valves →

Compression fitting Mechanical pipe joint

A pipe joint that seals by squeezing a metal or plastic ring (the "olive" or "ferrule") onto the pipe with a tightened nut. Does not need soldering or gluing. Common for joining poly pipe to brass fittings. Philmac UTC, Banjo poly fittings, and most rural waterworks use compression fittings.

See compression fittings →

Trade phrases Words we use about ordering and stock

Stocking, dispatch, and account terms used across the catalogue and order flow. Words we use about ordering, sending products, and trade accounts.

AEST Australian Eastern Standard Time

The time zone used in Victoria, New South Wales, Queensland, the ACT, and Tasmania during winter. Our 2pm same-day cutoff runs on AEST. In summer, eastern states except Queensland switch to AEDT (daylight saving), which is one hour ahead — but our cutoff time still tracks local Victoria time.

Trade account Account customer

A credit account for licensed trade businesses. Trade accounts get trade pricing on every product (typically 18 to 25 percent below retail), 30-day invoice terms, weekly invoicing, and priority same-day dispatch with a later cutoff. Apply once, use across every order.

Apply for a trade account →

Backorder Out of stock with reorder

A product that is currently out of stock but on order from the manufacturer. The product page shows the expected restock date. We accept backorders so your job stays in the queue, and we ship as soon as new stock lands.

Same-day cutoff Order before this time

The latest time we accept orders for same-day dispatch. Standard cutoff is 2pm AEST. Trade accounts have a later cutoff at 3pm AEST. Orders placed after the cutoff ship the next business day.

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