With alternative daily covers (ADC) becoming widely accepted in the industry, wouldn't it be nice to have an impartial group set basic standards for these products? The American Standards for Testing Materials (ASTM), West Conshohocken, Pa., thinks so, and has formed a committee to establish their minimum operational standards.
The manufacturing community instigated this process, says Mark Cadwallader, task group chairman for ASTM Committee D35. The committee is drafting an educational guidance document that will list individual requirements for various materials. Such flexibility is necessary due to the dissimilar products and to Subtitle D's open-ended guidance, Cadwallader says.
The guide will provide technical assistance to state regulators, engineers and landfill designers as they address ADC use in various landfill settings and under diverse conditions.
Fire control remains an issue of continuing discussion as committee members debate on whether or not to make combustibility a material requirement. "Different materials will exercise fire control in different ways," Cadwallader says.
"You've got non-combustible materials like dirt which will not burn, but do have porosity which allows the transfer of oxygen and methane gases from the landfill to support flames," he continues. "Then, you've got membrane tarps which do have some flammability relative to soil, yet they are an excellent barrier to gas and oxygen."
Work on the guide is expected to take another 18 months at least before a final document is drafted.