Brass
Copper-zinc alloy in two grades. DR brass (CW602N) — dezincification-resistant for outdoor, bore, and recycled water; mandatory under WaterMark for several application categories. Standard brass (CW617N) — cheaper, fine for indoor mains and gas service. The default valve and fitting material across Australian plumbing. Brass is a mix of copper and zinc, sold in two grades. DR brass resists corrosion and is required for outdoor, bore, and recycled water work. Standard brass is cheaper and is fine for indoor water and gas. Brass is the most common material for valves and fittings in Australian plumbing.
Two grades, one alloy family. Two grades of the same metal.
Brass is a copper-zinc alloy — typically 60–62% copper, 36–38% zinc, with small amounts of lead added for machinability. We stock two grades that differ by one consequential detail: whether they're dezincification-resistant. Brass is a mix of copper and zinc — usually about 60% copper, 38% zinc, plus a little lead to make it easier to machine. We stock two grades that differ in one important way: whether they resist dezincification.
Standard brass (CW617N). The default machinable brass for indoor mains-water service and gas. In treated mains water it lasts 30+ years. Cheaper than DR brass by roughly 30%. Standard brass (CW617N). The normal grade. Used for indoor water and gas. In normal treated water it lasts more than 30 years. About 30% cheaper than DR brass.
DR brass (CW602N). Same alloy with a small arsenic addition (0.04–0.10%) that prevents dezincification — the corrosion mechanism where zinc preferentially leaches out of the brass in aggressive water (chlorinated, soft, acidic, or mineral-laden), leaving a porous copper skeleton that fails under pressure. The arsenic locks the zinc into the copper matrix; the fitting survives decades in water that would destroy standard brass in 5–8 years. DR brass (CW602N). The same metal with a tiny amount of arsenic added (between 0.04% and 0.10%). The arsenic stops dezincification — a kind of corrosion where the zinc dissolves out of the brass in harsh water (chlorinated, soft, acidic, or mineral-rich), leaving the brass weak and full of holes until it fails. A DR brass fitting can last decades in water that would destroy a normal brass one in 5 to 8 years.
AS 2345 sets the dezincification test (max 200 µm penetration). WaterMark certification under the National Plumbing Code is granted to brass fittings that pass — and is mandatory in several application categories. Visually, you can't tell DR brass from standard brass. Trust the certification stamp, not the colour. The standard AS 2345 sets out the test that proves a brass fitting resists dezincification (no more than 200 micrometres of corrosion). WaterMark certification under the National Plumbing Code is given to fittings that pass — and is required for several types of work. You cannot tell the two grades apart by looking. Trust the certification, not the colour.
DR brass: outdoor and aggressive water. DR brass: outdoor and harsh water.
DR brass is the right answer whenever the water source isn't tightly controlled. Mandatory under WaterMark in several application categories. DR brass is the right choice when the water is not perfectly clean. The WaterMark approval requires it for several types of work.
Outdoor & underground Outdoor and underground
Garden taps, irrigation valves, buried ball valves, hose-bib fittings. Garden taps, irrigation valves, buried ball valves, and hose fittings.
Bore & rainwater Bore and rainwater
Bore-water tanks, rainwater diverters, pump fittings, transfer pumps. Bore-water tanks, rainwater diverters, pump fittings, transfer pumps.
Recycled & greywater Recycled and grey water
Class A recycled-water systems, greywater diversion, dual-supply plumbing. Recycled-water systems (Class A), grey water systems, and dual-supply plumbing.
Country & regional Country areas
Anywhere off mains supply, or where local water carries elevated chloride, sulfate, or hardness. Anywhere not on mains water, or where local water has high mineral content or chlorine.
Standard brass: indoor mains and gas. Standard brass: indoor water and gas.
Standard brass costs roughly 30% less than DR brass. For controlled water sources and gas service, the premium is dead weight — standard brass survives decades. Standard brass is about 30% cheaper than DR brass. For normal water and gas, the extra cost of DR is wasted — standard brass lasts decades.
Indoor mains-fed cold & hot Indoor mains water
Treated mains water in temperate cities. Standard brass survives 30+ years on mains supply. Treated mains water in normal cities. Normal brass lasts 30 years or more on this kind of water.
Indoor gas Indoor gas
Natural gas and LPG don't dezincify brass. Standard brass with AS 4617 gas certification is correct. Natural gas and LPG do not damage brass. Use normal brass with the AS 4617 gas approval.
Compressed air Compressed air
Pneumatic line fittings, air manifolds, instrument panels. Dry air doesn't dezincify. Pneumatic line fittings, air manifolds, and instrument panels. Dry air does not damage brass.
Decorative & finish Decorative and finish work
Polished or chrome-plated tapware, decorative valve handles, exposed indoor fittings. Polished or chrome-plated tapware, decorative handles, and visible indoor fittings.
Where another material wins. When you should use a different material.
Brass — even DR — has limits. Salt, strong chemicals, and high temperature each have a better material. Brass has limits. For salty water, strong chemicals, and very high temperatures, other materials work better.
Coastal & marine Near the coast or at sea
Salt-laden air will pit even DR brass over time. SS 316 is the marine default. See stainless steel → Salty air will damage even DR brass over time. Stainless 316 is the right choice for marine work. See stainless steel →
Aggressive chemicals Strong chemicals
Strong acids, bases, or chlorinated solvents will attack brass. Polypropylene for chemicals; PVC for cold acids. See PP → Strong acids, alkalis, or chlorine-based chemicals will damage brass. Use polypropylene for chemicals; PVC for cold acids. See PP →
High pressure / steam High pressure or steam
Above 25 bar or in steam service, brass loses strength. Carbon steel A105 to 100 bar. See carbon steel → Above 25 bar or in steam systems, brass gets weaker. Use carbon steel — works to 100 bar. See carbon steel →
Large bore mains (DN100+) Big mains pipes (over 100mm)
Above DN100 brass is impractical and expensive. Cement-lined ductile iron for potable mains; uncoated for non-potable. See ductile iron → For pipes bigger than 100mm, brass is impractical and expensive. Use cement-lined ductile iron for drinking water; uncoated for other water. See ductile iron →
Full specifications Full specifications
Composition, mechanical properties, and certified test data. Refer to AS 2345 and AS/NZS 4020 for full test methods. Material make-up, strength data, and test data. Look up AS 2345 and AS/NZS 4020 for the full test methods.
| Alloy designation Alloy code | CW602N (EN) · CZ132 (BS) |
|---|---|
| Copper Copper content | 61.0–63.0 % |
| Zinc Zinc content | ~36 % (balance) |
| Lead Lead content | 1.7–2.8 % |
| Arsenic Arsenic (the protective additive) | 0.04–0.10 % |
| Working pressure Max working pressure | 25 bar (2,500 kPa) |
|---|---|
| Temperature range Temperature range | −10 to +110 °C |
| Tensile strength Tensile strength | ≥ 380 MPa |
| DZR test Dezincification test | Max 200 µm penetration per AS 2345 Maximum 200 µm corrosion under AS 2345 |
| Density Density | 8.4 g/cm³ |
Australian standards that apply Australian standards that apply
AS 2345
Specifies test methods and limits for dezincification-resistant copper alloys. Maximum 200 µm depth of dezincification after standard immersion test. Sets out how to test brass for dezincification resistance, with a maximum allowed corrosion depth of 200 micrometres.
AS/NZS 4020
Mandatory leaching test for products in contact with drinking water. Verifies no chemical migration that affects taste, odour, or appearance. A required test for products that touch drinking water. Confirms nothing leaches into the water that changes taste, smell, or how it looks.
WaterMark Level 1
National Plumbing Code certification. Required by law on regulated potable-water installations across Australia. A certification under the National Plumbing Code. Required by law for drinking-water installations across Australia.
EN 12164 / EN 12165
European standards for wrought and forged copper-alloy products. CW602N is the European code most catalogues use. European standards for brass products. CW602N is the European code that most catalogues use to identify DR brass.
Brass products we stock Brass products we stock
468 SKUs total — 312 in DR brass (CW602N) and 156 in standard brass (CW617N). Ball valves, check valves, pressure-reducing valves, compression fittings, ferrule valves. Banjo, Apex, Reliance, Caleffi. 468 products in total — 312 in DR brass and 156 in standard brass. Ball valves, check valves, pressure-reducing valves, compression fittings, and ferrule valves. From Banjo, Apex, Reliance, and Caleffi.
Related materials Materials worth comparing
When brass isn't the right answer, here's what is. When brass is not the right choice, these are the alternatives.