Field Installations of Polyamide 12 (PA12) in Natural Gas Distribution Systems

This paper presents an overview of the first two high pressure polyamide 12 (PA12) natural gas plastic pipe field installations with operating pressures up to 250 psig. The overview includes the Special Permit requirements, layout, materials, and operating pressures, as well as the installation methods employed to complete the installations.

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The natural gas industry has long understood the advantages associated with plastic piping materials. In addition to being easier to handle and join, plastic piping materials eliminate the need for long-term corrosion control and the associated costs. Since the midhas been an on-going effort to utilize the plastic piping system at higher operating pressures. The Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) has amended the Federal Code to allow the use of the PE materials at increased pressures up to 125 psig. Concurrently, the industry has also sponsored research into new materials that can operate at pressures up to 250 psig while maintaining the overall benefits of plastic piping materials. One of the most promising candidates is polyamide 12 (PA12).

In order to be proactive, GTI initiated a comprehensive research program to validate the feasibility for the use of Polyamide 12 (PA12) in high pressure gas distribution applications through comprehensive laboratory testing and field experiments. The results of this research program demonstrated that the PA12 materials appear to be a very promising candidate material for high pressure gas distribution applications.

Based on the success of periments, the first two PA12 installations were installed in the public right of way on a natural gas system under a Special Permit.