15-1014 v3.X A606-4 Steel


Hello, our team is trying to determine if A606-4 weathering steel (“Corten”) is an acceptable exterior metal cladding for our project in regards to the Red List. A strong basis of the design of our project is its connection to the history and context of the site; an important element of this connection is the use of weathering steel on the building exterior. Weathered steel does not have a coating, which reduces the amount of material in the project. From the MSDS for cold rolled sheet steel provided by the cladding fabricator for their A606-4 steel RustWall cladding, it contains Red List alloy ingredients in small amounts: cadmium, lead, arsenic. The CAS number for Chromium in the alloy is not the same CAS number as Chromium VI. Also according to the cladding fabricator, these Red list alloy ingredients are present in all sheet steel, in different percentages. The 3.0 Materials Petal Handbook states under Red List on page 10 “METALS: Metals that have a standardized CAS number, such as steel...do not need an additional ingredients list for the constituent alloys.” The MSDS reports I have found for plain coil and sheet steel and rebar also list these alloy ingredients, and say that the CAS number for their steel is “N/A.” The only CAS number I have found for steel is for plain Carbon Steel. Can our team apply the intent of the METALS determination above to A606-4 weathering steel and use A606-4 steel cladding on our project? I have attached the sheet steel (Cold roll) MSDS and A606-4 cold roll metallurgical test report provided by the cladding fabricator, and a RustWall product description. The A606-4 metallurgical report does not list lead, cadmium or arsenic.


Recycled steel and galvanized metal products are included under the Unintentional Trace Amounts clarification in the v3.0 August 2014 Materials Petal Handbook (MPH p10). Based on the information provided, the RustWall product is included in this clarification. As stated under Metals (MPH p11) the ingredient for sheet steel can simply be listed as steel. For products included in the Unintentional Trace Amounts clarification, a full list of all intentionally added ingredients is required. For this specific product, Nucor will need to confirm that the Red List ingredients listed on the sheet steel MSDS are present as a result of the steel recycling process and are not intentionally added during Nucor's manufacturing process.

Post ID 3298

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