Governments and consumers are more concerned than ever with sustainability and public health issues that stem from the global water industry – including its water heater market. Recent surges in energy prices have increased demand for more energy efficient heaters, boilers and heat pumps. This trend has driven up global sales of condensing boilers, as well as small tankless electric and gas-powered water heaters – which may be up to 34% more energy efficient than conventional storage tank alternatives.
Public health organizations are leveraging advanced toxicological insights and impurity analysis techniques to drive public awareness of adverse health risks related to poor drinking water quality. As a result, more consumers are concerned with toxic lead levels found in drinking water, due in large part to the Flint, Michigan water crisis. This public health issue is widespread according to a National Resources Defense Council study estimating that over 61 million Americans used drinking water systems in which lead levels above the recommended 5 parts per billion (ppb) limit were detected between 2018 and 2020.
To protect the health of consumers, key regulatory bodies, including the National Sanitation Foundation (NSF), have rapidly altered standards for manufacturing drinking water components. These changes include new, stringent material regulations for plumbing parts – including water heaters, heat pumps and boilers.
Thermoplastics, including polyamide 66 (PA66), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), and polyphthalamide (PPA) are replacing brass and copper material solutions to minimize lead-related health risks, improve end-product sustainability and reduce manufacturing costs. PA66 and PPO are popular options, as they are cost-effective and offer high ductility that helps streamline production. Yet, in addition to providing limited design flexibility and demonstrating high leachable levels in warm water applications, these materials may lead to supply disruption and regulatory compliance issues.
For water heating equipment manufacturers, balancing design criteria and performance requirements for technical parts are an ongoing challenge. Continuous hot water exposure decreases the mechanical strength and dimensional stability of PA66, while built-in stress from molding PPO can lead to end-part assembly issues. The reliability of PA66 and PPO is often further compromised when molded into thin-walled components.
Manufacturers also need to address the risk of supply chain disruptions that slow down production. These delays often result from changes to water contact regulations, including NSF 61 and KTW-BWGL – which recently began requiring third-party supervised sample testing to certify materials. However, replacing PA66 and PPO often requires expensive re-tooling. And rushing material change programs to avoid product launch delays may compromise the performance of end-parts – resulting in costly unit repairs or water damage caused by leaks.
To overcome these challenges, manufacturers are looking for low-leaching, high-performance thermoplastics, while adopting contingency plans to ensure they have a steady supply of reliable solutions.
