KEMPER Gunmetal - The Material
KEMPER gunmetal, the ideal valve and
plumbing material – now and in the future
Gunmetal is a valve and plumbing material standardised according in accordance with DIN 50930-6 / DIN EN 982, which is particularly suitable for sanitary installation engineering thanks to its wide range of possible applications, for example as a material for stop, protection and regulating valves, as fitting material for pipe system components and as a construction material in water and filter technology as well as in water treatment.
Gunmetal statements relating to DIN 50930-6, the list of the German Environment Agency "UBA" (UBA positive list of metallic materials hygienically suitable for drinking water) or the 4 MS list (Four Member States List):
"Gunmetal can be used without limitation in drinking water in Europe".
The composition of gunmetal alloy used by KEMPER meets the requirements of DIN 50930-6. The element contents of lead (Pb) and nickel (Ni) are so limited that the material meets the latest requirements of the Drinking Water Directive.
Series of tests in laboratories accredited according to German and European standards have duly confirmed these results in recent years. In the tests carried out, it was proved that after a brief running-in phase, all relevant measured migration values were below half of the parameter values, which for lead is below 5 μg/litre.
As a result, gunmetal is on the list of the UBA and the 4 MS list and is free for use in drinking water installation. Through countless attestations in the form of 3.1 certificates, the gunmetal used by KEMPER since 2001 has proved that the mechanical characteristic values are significantly higher than the minimum values of the DIN EN 1982 standard. The reasons for the positive results of KEMPER gunmetal are the corrosion resistance of the material, which is well known on the market, and the components made from this.
You can download the latest version of the UBA positive list and the 4 MS list from the website of the German Environment Agency: http://www.umweltbundesamt.de/themen/wasser/trinkwasser/trinkwasser-verteilen/anerkennung-harmonisierung-ms-initiative
Corrosion behaviour of gunmetal
Gunmetal is one of the most corrosion-resistant copper materials and is characterised by outstanding resistance to external influences.
The special material suitability even under extreme water conditions makes gunmetal ideal for use in drinking water installations. In addition to use in the drinking water sector, the material gunmetal has also proved successful with water containing carbonic acid and salt. This is why i is also frequently used in the mining industry.
As gunmetal consists only of alpha structures due to its high copper content and contains only 5% zinc, this material cannot dezincify in the usual applications, and neither surface nor plug dezincification occurs.
Stress crack corrosion
On account of the special material structure, stress crack corrosion is also unknown in gunmetal.