6Mil - 20'x100' Polysheeting String Reinforced Flame Retardant 6Mil - 20'x100' String Reinforced Flame Retardant Polyethylene Sheeting/ Containment & Construction Film. 6Mil - 20'x100' String Reinforced Polysheeting /roll, Mil - 20'x100' String Reinforced Polyethylene Sheeting/ Containment & Construction Film. Consists of two sheets of high strength flame retardant film laminated with a third layer of molten polyethylene. Reinforced with cross tied polyester tire cord. Very durable, tear resistant, vapor barrier, ideal for containment. Ships 25 rolls/ pallet. Meets ASTM designation: D4397-91 and all associated specifications.