AWWA C800, Underground Service Line Valves and Fittings, was built around the use of one brass alloy, C83600, also known as leaded red brass, favored for its manufacturability and low cost. Over the last two decades, the waterworks industry has transitioned to brass alloys that meet the definition of lead-free for most surfaces contacting potable water. The transition was possible for a broad range of waterworks products because there are many lead-free brass options available to the market, however, only three lead-free alloys were available for C800 products, and all three were bismuth-based brass.

In 2018, the U.S. Department of the Interior identified bismuth as one of 35 critical minerals. “Critical” is defined as 1) a non-fuel mineral essential to the economic and national security of the United States; 2) the supply chain of which is vulnerable to disruption; and 3) serves an essential function in manufacturing product which would have significant consequences if absent. While recognition of a mineral as critical doesn’t disqualify an alloy from use, it should be considered in a larger evaluation strategy.

AWWA revised the C800 standard to include three lead-free, silicon-based brass options. Given the supply chain concerns with bismuth and availability of proven lead-free alternatives, Mueller Water Products built a new state-of-the-art foundry to manufacture lead free silicon-based brass C87850 products in 2020. This includes gate and specialty valves, hydrants, and service brass including corporation valves, curb valves, meter valves, check valves, service saddles and fittings, as well as meter pits and meter setters.

Research and innovation drive competition in a healthy industry, and competition leads to improved designs and higher quality products for the end user. It also provides better price stability through mitigation of supply chain risks. Design engineers have been searching for new and improved ways to address the changing standards and regulations by creating better products while focusing on the most pressing issues for utilities, namely aging infrastructure.

When it comes to materials, we know that some are better at standing the test of time and the tough and varying conditions of underground water distribution systems. Accordingly, the most cost-effective solution is having a long-lasting, tough product. In the case of C87850 silicon-based brass, this alloy is nearly twice the minimum tensile strength and fifty percent stronger in minimum yield than C89833 bismuth-based brass and C83600 leaded red brass. These attributes provide superior mechanical strength and structural integrity that has not previously been available in these products.

Other waterworks products, such as fire hydrants and gate valves, have utilized lead-free silicon-based brass for decades and have already met performance criteria in product standards set by the American Water Works Association (AWWA), Underwriters Laboratories (UL), and FM Approvals (FM). The C87850 alloy also consistently exhibits zero dezincification under the ISO 6509 test which has a pass criterion of up to 200 μm. Mueller conducted detailed tests and investigations and discovered C87850 silicon-based brass consistently exhibits zero dezincification when exposed to a corrosive bath for 144 hours under UL requirements, which is far and above the 24 hours specified under the ISO 6509 parameters.

Manufacturing new products today requires adherence to higher standards of environmental sustainability that can add to the initial cost, but these higher standards are better for workers, the environment and the use of natural resources. Silicon is the second most abundant element in Earth’s crust while bismuth, a by-product of lead mining, is only about twice as abundant as gold. In terms of manufacturing, the lower melting temperature of some silicon-based brass alloys reduces energy consumption and carbon dioxide emissions during both initial melt and while maintaining the charge in a molten state. The lower melting temperature reduces other hazardous fume emissions as well as generation of silica and flue dust.

While some manufacturers continue to use leaded red brass for non-wetted infrastructure components and products, Mueller has committed to implementing C87850, lead-free material in all components of our service brass products as well as hydrants and gate valves; proactively working to reduce lead in all water infrastructure and the copper alloy recycling stream.

Silicon-based brass service line valves and fittings are a product evolution that utilities can now use when replacing aging infrastructure and in new construction. They not only have a long-life expectancy but will also help the industry meet environmental and sustainability goals. With more manufacturers investing in research and development activities to accelerate product development, utilities will have better tools to repair and replace infrastructure.

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