Dezincification Resistance (DZR) testing evaluates the resistance of copper alloys against corrosion that can weaken plumbing components and reduce service life.
PUB has tightened the requirements for copper alloy water fittings to align with international potable water standards.
Under the revised requirements, selected copper alloy grades will be phased out for potable water use from 1 March 2027 (WSN 92413/90/202301/COPPERALLOY).
| Allowed for supply between 1 March 2023 to end February 2027 | Allowed for supply from 1 March 2027 onwards |
|---|---|
|
Copper alloy grades as listed in the 4MSI Positive List of Compositions (which also covers CW511L, CW625N, CW626N, CW724R and CW725R) |
| Symbol | Number | Cu (%) | Al (%) | As (%) | Fe (%) | Mn (%) | Ni (%) | P (%) | Pb (%) | Si (%) | Sn (%) | Other Elements | Zn (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CuZn38As | CW511L | 61.5–63.5 | ≤ 0.05 | * 0.02–0.1 | ≤ 0.1 | * ≤ 0.1 | * ≤ 0.1 | - | * ≤ 0.1 | - | ≤ 0.1 | ≤ 0.2 | Rem |
| CuZn35Pb1.5AlAs | CW625N | 62.0–64.0 | 0.5–0.7 | 0.02–0.15 | ≤ 0.1 | ≤ 0.1 | ≤ 0.2 | - | 1.2–1.6 | - | ≤ 0.3 | ≤ 0.2 | Rem |
| CuZn33Pb1.5AlAs | CW626N | 64.0–66.0 | 0.8–1.0 | 0.02–0.15 | ≤ 0.1 | ≤ 0.1 | ≤ 0.2 | - | 1.2–1.7 | - | ≤ 0.3 | ≤ 0.2 | Rem |
| CuZn21Si3P | CW724R | 75.0–77.0 | ≤ 0.05 | - | ≤ 0.3 | ≤ 0.05 | ≤ 0.2 | 0.02–0.1 | ≤ 0.1 | 2.7–3.5 | * ≤ 0.2 | ≤ 0.2 | Rem |
| CuZn33Pb1AlSiAs | CW725R | 64.0–67.0 | 0.1–0.3 | 0.04–0.08 | ≤ 0.3 | ≤ 0.04 | ≤ 0.2 | ≤ 0.02 | * 0.4–0.6 | 0.1–0.3 | ≤ 0.3 | ≤ 0.2 | Rem |
*Contents restricted by 4MSI.
At Singapore Test Lab (STL), we provide comprehensive DZR testing services for copper alloy water fittings in full compliance with PUB’s requirements. With our expertise, you can have complete peace of mind — we take the guesswork out of material selection so you can focus on what matters most.
For more information about STL’s Chemical Testing Services, please contact us at contact@singaporetestlab.sg