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Use of Fly Ash in WeatherBoards™ Fiber Cement Siding

Updated May, 2010

Fly ash is a key component used in the manufacture of CertainTeed’s fiber cement siding products. 

 The U.S. Environmental Protection Agency (EPA) recognizes fly ash as an industrial by-product of the coal combustion process in electricity-generating power plants.  The EPA supports the beneficial reuse of fly ash in construction applications because it is safe and reduces the amount of coal combustion residue sent to landfill.

 In addition to its beneficial reuse in our fiber cement products, fly ash has been used in concrete since the 1930’s.  Most notably, it has been used in several construction projects and prominent buildings, including the Ronald Reagan Government Office building, home to the Environmental Protection Agency (EPA) in Washington, D.C.

 Through a proprietary process that combines fly ash with Portland cement and other components, CertainTeed manufactures a fiber cement board that encapsulates the fly ash, resulting in a highly durable and sustainable product.  Using currently available test methods, studies of WeatherBoards™ fiber cement siding  indicate that CertainTeed’s fiber cement products meet all applicable Occupational Safety and Health Administration (OSHA) and other regulatory standards.

 On May 4, 2010, the Environmental Protection Agency (EPA) proposed two alternative draft rules to increase federal oversight of the disposal of Coal Combustion Products (CCPs).  The draft rules make it clear that the EPA continues to strongly support the beneficial reuse of CCPs in concrete, cement, wallboard and other encapsulated applications such as fiber cement.  Under both proposals, the EPA stated that there will be no change in the regulatory status of coal ash when recycled as a component in these, and other products.

 In a press release, Mathy Stanislaus, the EPA’s Assistant Administrator for the Office Solid Waste and Emergency Response, emphasized that:
"EPA supports the legitimate beneficial use of coal combustion residuals.  Environmentally sound beneficial uses of ash conserve resources, reduce greenhouse gas emissions, lessen the need for waste disposal units, and provide significant domestic economic benefits. This proposal will clearly differentiate these uses from coal ash disposal and assure that safe beneficial uses are not restricted and in fact are encouraged."
The EPA is seeking public comment on the proposals, including suggestions on how best to publicize the continued exemption of beneficial uses from regulation.   Given CertainTeed’s strong belief in the environmental benefits of our fiber cement fly ash formulation, we will provide the EPA with comments expressing our support for a regulatory approach that continues to allow the safe and beneficial use of CCPs in construction products while establishing appropriate regulations to ensure the safe landfilling of CCPs.

For additional information about the proposed regulation, refer to www.epa.gov/coalashrule.

To download a copy of CertainTeed's Corporate Statement on the Use of Fly Ash, please use the link under Helpful Resources.


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