DZR Components: What They Are and Why They Matter in Plumbing Systems
DZR brass resists dezincification, where zinc dissolves out of the brass, weakening the alloy. Learn when you should choose this material in your projects.
Last Updated: Sep 3, 2024
DZR (Dezincification Resistant) or DR Brass is a type of brass used for manufacturing, which gives resistance to dezincification corrosion. Products that offer Dezincification Resistant properties will often be marked with the "DR" mark, as above.
What Is Dezincification?
Brass is a widely used metal alloy, made of copper and zinc. In certain circumstances, when exposed to particular combinations of pH and concentrations of chlorides it can experience a severe form of corrosion known as dezincification. This is where the zinc dissolves out of the brass, weaking and compromising the mechanical properties of the alloy.
In relation to HVAC applications, dezincification can result in system failure by causing leaks, blockages or even ruptures. It is therefore rightfully a major consideration when it comes to system design.
When Do I Need To Be Concerned About Dezincification?
In the UK, it is mandatory for fittings that are going underground to be dezincification resistant.
Potable water is unlikely to cause dezincification, but if it is capable, or where distribution systems might introduce fluids that may cause dezincification, you should use DZR fittings. If you are unsure, advice can be sought from your local water authority to understand if you need to consider DZR components for your project.
Avoiding Dezincification At The Point Of Manufacture
Our role is to manufacture products that offer DZR (Dezincification Resistant) properties. To create components that resist dezincification, selecting the appropriate material is essential.
While copper and bronze are naturally immune to dezincification, they present challenges in manufacturing. Brass, however, is the most practical choice for high-volume production. To ensure resistance to dezincification, we use a specialised grade of brass.
DZR brass typically conforms to specifications such as CW602N, CW626N, or CW6265, which have a lower zinc content than standard brass rods. Although traditional guidelines suggest that zinc content below 15% helps prevent dezincification, stamping and machining processes often require higher zinc levels. By incorporating inhibitors, DZR brass maintains dezincification resistance even with higher zinc content. In line with UK standards, our DZR brass contains small amounts of arsenic (0.02–0.15%) and nickel (0–0.3%).
This material undergoes the usual manufacturing processes, with additional steps for stress relief through heat treatment. Careful management is crucial to prevent cross-contamination between DZR and non-DZR brass during production.
What Does This Mean For You?
If your project requires DZR components, please ensure you specify this when placing your order with us. Flowflex Compression provides DZR components within our Compression range. However, since the corrosion resistance of DZR components can be affected at temperatures above 400°C, we offer bronze products in our Copper ranges instead.
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