Installers, contractors and specifiers are being urged to not let fittings be the weak link when specifying below-ground, pre-insulated pipe for drinking water applications.
According to pipework manufacturer REHAU, low-quality brass fittings can undermine an otherwise high-performance installation through lead leaching, corrosion and premature failure, compromising underground district heating and drinking water infrastructure. With 34% of UK plumbers over 55 and approaching retirement, the company believes that understanding of the performance qualities of brass is fading, leaving a potential knowledge gap around what is fit for purpose.
Franz Huelle, head of technical at REHAU Water Technologies, comments: “A chain is only as strong as its weakest link, and a drinking water system is only as strong as its weakest component. Specifiers can spend a considerable amount of time ensuring that their choice of pipework is correct, only to be let down by the fittings that connect them.
“When two systems appear to meet the same headline requirement, price naturally becomes the differentiator. But two systems described as ‘having drinking water approval’ don’t necessarily deliver the same long-term performance everywhere in the UK.”
Varying levels of water hardness in the UK can cause drastically different reactions with standard brass fittings. In the South East, where water is harder, the higher calcium content reacts favourably with chlorine, but in the North, where water is softer, fittings may be at risk of dezincification. Here, the reactive zinc component of the copper-zinc alloy can dissolve, potentially leading to leaching and even total failure.
This is a key reason why dezincification-resistant (DZR) brass had been developed in the UK many decades ago. In more recent times, the push to remove lead from drinking water has resulted in lead-free, corrosion resistant brass alloys, though Franz believes that awareness of this is fading due to a lot of expertise having left the industry over recent years, and more installers approaching retirement.
“When lead-free, corrosion resistant brass alloys offer a higher purchase point than standard brass alloys without much explanation as to why, it’s easy to see how long-lasting drinking water fittings suitable for any part of the UK get value engineered out of the equation.
“However, compliance can still be ensured by asking the right questions of your supplier. First, don’t just accept ‘drinking water approved’ – ask whether the certification is based on UK requirements, and what aspects of the system it covers. Second, query what material the fittings are made from, and whether they’re fit for purpose in the long run, and suitable for the application and water hardness at hand. Only through this approach can we can create underground drinking water systems that remain fit for purpose for years to come.”
