What Is DZR?
DZR (Dezincification Resistant) Brass is a type of brass used for manufacturing some of our components, which gives resistance to dezincification corrosion.
What Is Dezincification?
Brass is a metal alloy widely used in the water distribution industry, 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, compromising the mechanical properties of the alloy.
In relation to plumbing 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?
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 such water you should use DZR fittings. In these cases 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
In order to produce components that can resist dezincification, we have to use the right material. Copper and Bronze are both immune to dezincification and DZR Brass is highly resistant. Copper and Bronze however have drawbacks when it comes to manufacturing, with Brass being the most practical for high volume production.
When using DZR brass for manufacturing components we use the CW602N, CW6265 or CW626N specification of brass rod, which has a lower zinc content than standard brass rod. Traditionally, <15% zinc content has been the accepted maximum limit for avoiding dezincification, however for stamping and machining brass we need zinc contents higher than this. Adding inhibitors to the brass allows it to have a higher zinc content, yet still be resistant to dezincification corrosion. We use DZR brass as per UK specifications which contains some Arsenic (0.02 – 0.15%) and Nickel (0% – 0.3%).
This material will follow all normal routes of manufacture, with extra steps involved for stress relief through heat treatment. Extra care also has to be taken that there is no contamination between DZR and non-DZR brass.
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Figures are indicative only and not for reference.
What does this mean for you?
DZR components are more expensive due to the higher copper content and extra manufacturing processes involved.
If you require DZR components for your project, you will have to specify this with us when ordering. Flowflex Compression offers DZR components, however as the corrosion resistance of DZR components can be compromised when heated in excess of 400°C we only offer Bronze in our End Feed range.
For more information on DZR product codes, please see our Compression Technical Guide.
For more information on Bronze products in our End Feed Range, please see our End Feed Product List.