Teel adds nylon to the gas distribution pipeline mix

Plastic pipe for natural gas distribution is usually high density polyethylene, but in Henderson, Ky., Teel Plastics Inc. extruded nylon 12 gas pipe to replace steel.

This month, Best Practices brings you something new in gas distribution pipe.

Teel President Tom Thompson this was the first installation of nylon 12 pipe for gas distribution.

Thompson said nylon can handle pipe up to 250 psi of pressure, while HDPE is used up to 125 psi. Thompson said codes for the expanded use of nylon gas distribution pipe were officially approved in January 2019. The Pipeline and Hazardous Materials Safety Administration's Mega Rule approved greater use of plastic pipe in high-pressure applications, including HDPE and nylon 11, which already were in use, and allowing nylon 12 for the first time.

Evonik Industries supplied the nylon 12 resin.

McElroy Manufacturing Inc., which makes fusion machines for joining pipe in the field, publicized the news.

Teel provided more than 2,800 feet of 200 psi nylon 12 pipe for the project.

Owen Reeves, gas system director for Henderson Municipal Gas, said he and his department were mainly drawn to using nylon 12 for its ease of installation compared to steel. And the city was looking at a tough installation job: running the gas pipe through an industrial section of Henderson.

To minimize disruption, the city installed the pipe under driveways and roads using horizontal drilling. Crews pulled the pipe through the bored holes and then fused the sections together.

But the main reason Henderson picked nylon 12 over steel was the joining method. The butt-fusion process the city used was much easier and faster than welding required for joining steel pipe lengths, city officials said. The nylon pipe installation took only about three days, and each fusion took around an hour to complete, including placement and alignment, Reeves said. Steel pipe probably would have required two or three weeks, he said.

When Henderson Municipal Gas was planning the project, Reeves was referred to Evonik, which then referred him to Teel in Baraboo, Wis.

In addition to the nylon pipe, Teel also provided the city with specially designed "weak link" mechanisms to help during the installation. These were used in each section of the pipe to help ensure that, as it was pulled through the boring holes, the links would break in case of a snag, instead of stressing the pipe itself.

"So far we've been very happy. Teel did a great job," Reeves said. "They have delivered as promised and supported us."

Teel's director of growth strategies, Christian Herrild, said customer support is very important.

So what's the future for nylon 12 gas pipe? Thompson, the Teel president, said since the Henderson project, the company is working on other jobs, including one where steel natural gas pipe is leaking under a river.

Nylon offers an interesting new material for pipe in the natural gas market. Once again it shows how plastic is giving traditional materials — in this case steel — serious competition.

Since pipe is buried underground, it's one of those products people never think about --- until it breaks.