If external corrosion is a concern, the Ductile Iron Pipe Research Association (DIPRA) recommends the use of loose film polyethylene encasement, purchased and installed in accordance with AWWA C105. Polyethylene encasement is the most cost-effective means of mitigating external corrosion under the broadest range of possible conditions.

 The subject of external corrosion on underground metallic pipelines has been written about extensively, with many “experts” extolling the absolute necessity for elaborate corrosion control systems.  While the debate continues, two facts are often overlooked:

  1. Extensive soil surveys conducted by a multitude of agencies throughout the country indicate that only about 10% of the soils in the United States are aggressive toward ductile iron products.
  2. Loose film polyethylene encasement has over 45 years of service history protecting your investment in millions of feet of cast and ductile iron pipe.

Sometimes called “Polywrap,” loose film polyethylene is inexpensive, easy to install, does not degrade in service and therefore, requires no maintenance.

You may sometimes encounter corrosive conditions so severe that you should consider methods other than polyethylene encasement. When in doubt, ask your U.S. Pipe Sales Representative to arrange a free consultation with a DIPRA Regional Engineer. DIPRA Regional Engineers are NACE International-certified Corrosion Specialists, and will help you make the right decision for your specific project requirements.