Polyethylene encasements are a cost-effective way to prevent corrosion and extend the life of ductile iron pipe systems. AA Thread’s Polywrap works by creating a barrier between the corrosive soil and the pipe and effectively slowing down the corrosion rate. This is achieved by creating an environment where the initial oxygen buried with the pipe is depleted, creating minor surface oxidation. The Polywrap prevents any further oxygen from entering the space between the wrap and the pipe, thus preventing any further corrosion of the pipe. Polywrap also has a high dielectric strength that combats stray currents in the soil, which can also corrode ductile iron.
Polyethylene encasements (Polywrap) create a barrier between the corrosive soil and the pipe.
Over the years, concerns have been raised about this initially-occurring surface oxidation as well as bacteria in the soil that may seep between the wrap and the pipe causing anaerobic corrosion. This has led to the development of enhanced polyethylene made from 8 MIL thickness, linear low density polyethylene and manufactured according the ANSI/AWWA C105/A21.5. This standard requires that the Polywrap be manufactured from 100 percent virgin polyethylene resins with properties that meet certain tensile strength, elongation, dielectric strength, impact resistance, and tear resistance. In addition to these properties, the enhanced polyethylene is manufactured with additives that help combat the initial corrosion and anaerobic bacteria. WW
AA Thread Seal Tape Inc. is exhibiting at AWWA’s ACE18 expo in booth 21098. Learn more at aathread.com.
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