• Lead Free Alloys


    Not all alloys are created equal
    Foresight ahead of its time


    For over two decades, NIBCO has been at the forefront of development and commercialization of lead-free*plumbing products. In 1992, NIBCO was the first domestic manufacturer to introduce a line of lead-free brass and bronze fittings and valves using a bismuth-based alloy into the domestic plumbing market. Today, NIBCO manufactures a vast collection of lead-free valves, fittings and flanges. The HydraPure® line is manufactured from the silicon-based Performance Bronze™ alloy, which exhibits mechanical properties far exceeding traditional plumbing alloys. Vision and experience have enabled NIBCO to stay ahead of regulations, ahead of the industry – and AHEAD OF THE FLOW®.

    When NIBCO introduced its first generation of HydraPure® lead-free products in 1992, NIBCO utilized the copper-bismuth alloy C89844. We discovered first hand that replacing lead with bismuth and other constituents not only affects manufacturability and product installation, but also service life – foresight way ahead of its time. Similar alloys, including the copper-bismuth alloys C89833 and C89836, are still being used by many plumbing valve and fitting manufacturers today.

    However, our level of expertise with not only research, development, and testing of lead-free alloys, but also with production methods and quality controls, have given us a better understanding of the many technical pitfalls exhibited by bismuth-based alloys.

    For these reasons, among others, rather than merely settling on a lead-free copper bismuth alloy, NIBCO chose to focus on the high quality, silicon-based Performance Bronze™ family of copper alloys: C87600, C87850 and C69300. In 2009, NIBCO launched a new generation of HydraPure® silicon Performance Bronze™ valves, fittings, and flanges in compliance with changing lead-free plumbing requirements.

    NIBCO HydraPure® silicon Performance Bronze™ products benefits include:

    • 3rd-party tested corrosion resistant (dezincification and stress corrosion cracking)
    • NSF/ANSI 61-8 Commercial Hot (180°F) – includes Annex F & G
    • NSF/ANSI 372
    • Meet or exceed MSS standards
    • 5-year, 125% warranty
    • Easy to install
    • Easy to identify as lead-free

    The case for silicon lead-free alloys:


    A discussion of bismuth copper alloys and silicon copper alloys needs to start with the elements themselves.  

    Basic physical properties:
    Silicon not only adds significant strength to copper alloys (see chart below), but elemental silicon also melts at an impressively high temperature of 2,572°F. The melting point of silicon, as a constituent in copper alloys, is high enough that it is not a factor with respect to manufacture, installation, or service and can be brazed with confidence.

    Alloy Comparison - Typical Mechanical Properties (Room Temperature)

    Alloy Description % Lead Ultimate Tensile Strength (psi) Yield Strength (psi) % Elongation
    C84400 Semi-Red Bronze

    7%

    34,000 15,000

    26

    C92200 Navy Steam Bronze

    1.50%

    34,000 16,000

    22

    C89833 Bismuth based LF alloy

    ≤.25%

    37,000 17,000

    28

    C89836 Bismuth based LF alloy

    ≤.25%

    33,000 15,000

    20

    C87600 Silicon Performance Bronze™

    ≤.25%

    66,000 32,000

    20

    C87850/C69300 Silicon Performance Bronze™

    ≤.25%

    63,000 26,000

    25

     


    Bismuth is very brittle in contrast to lead, which is very ductile, and neither element adds strength to copper alloys. The melting temperature of bismuth is 520.7°F, which is significantly lower than the 621.5°F melting point for lead. Solder installation typically requires minimum temperatures between 420°F and 590°F. Still more aggressive heating is required for hard soldering, silver soldering, and brazing which are done at temperatures exceeding 700°F. During such heating, internal stresses resulting from localized expansion and contraction forces are created within the component alone or in combination with service-induced stress can lead to component failure produced from bismuth-based alloys.  Bismuth-based lead free alloys should never be brazed.

    Corrosion Resistance


    The plumbing industry has come a long way in terms of corrosion resistance and should not go backwards when it comes to the implementation of lead-free* alloys. Corrosion as applied to bronze/brass is primarily related to dezincification and stress cracking. Many factors within the manufacturing process can affect corrosion resistance of the actual final product; in turn, published data presented by the alloy producer can no longer be considered the most reliable evaluation. Rather than determining expected product corrosion resistance strictly by the results of alloy testing or by basic alloy constituent make-up, NIBCO has products third-party tested to industry-accepted ISO standardized tests to substantiate actual corrosion performance. The only way to have full assurance is to test the assembled product that is actually installed in the plumbing system. NIBCO HydraPure® silicon Performance Bronze® valves and fittings have achieved the highest level of success in the following standardized tests:

    • Dezincification Resistance – BS EN ISO 6506: 1995 Corrosion of Metal Alloys
    • Stress Corrosion Cracking – ISO 6957: 1988 (E) Copper Alloys

    See the 3rd party results from Corrosion Testing Labs

    Health Effects


    NIBCO has always held to the basic tenet that replacement of lead in plumbing alloys should not bring about additional health concerns. Just as levels of lead in drinking water may be regulated in some jurisdictions, other constituents may also leach from the lead-free* plumbing alloy and may be regulated as well in the future. Bismuth, a by-product of lead mining, may not currently be considered in the same category as lead in terms of research regarding potential health hazards, though NSF International did publish action levels in 1995 limiting the maximum allowable concentration of bismuth in a single product. In contrast, it should be noted that silicon is NOT a regulated substance and there is no published information indicating that silicon may pose drinking water health effects.

    Source of Supply


    The USA has no bismuth deposits. China, Mexico and Peru are the leading producers of bismuth, with China accounting for 40% of world production. Bismuth is only about twice as abundant as gold and is extracted from the earth's crust primarily as a by-product of lead mining, whereas silicon is the second most abundant element within the earth's crust, second only to oxygen.

    3rd Party Reassurance


    NIBCO HydraPure® valve and fitting products have achieved the highest level of stringent testing within NSF/ANSI 61 drinking water standard for section 8, in-line devices. Within the NSF/ANSI 61 standard, there are three temperature options of which NIBCO elected to achieve the most stringent: Commercial Hot (180°F). In addition, HydraPure® products are also listed to NSF/ANSI 372, Weighted Average Lead Content of Water Contact Components, which satisfies new requirements of the Safe Drinking Water Act taking effect nationally on January 4, 2014.