Polythylene Natural Gas Pipe

[warrenshudson]

If I was to use yellow polythylene pipe for a 100' run to a garage, and the pipe stayed underground, how does one transisition to black pipe, so the installation is code compliant?

[Bob Wheatley]

Codes vary but typically you would use a wrapped steel transition riser. They come in straight risers but the most common is the 90 degree type. Whoever is selling you the pipe should sell these too. A tip: Do NOT use pipe dope on the transition joints. You will create a future leak due to the ABS components which will not tolerate oil based pipe lubricants. Use teflon.

Bob Wheatley

[warrenshudson]

Thanks. Also- what is the difference between the yellow polythylene pipe designed for gas, and garden variety black polythylene pipe? I am not planning on using the black stuff, but just curious, as the gas pipe seems more expensive.

[Bob Wheatley]

There are different ANSI and ASTM requirements for gas than water and or sewer. Each has component composites unique to itself and different SDR (standard dimension ratio) standards. Do NOT use the black polyethylene for gas.

Here's a link that might be helpful for you to see the risers and see what they look like.

Bob Wheatley

[warrenshudson]

The reason I ask is that a friend used the black stuff underground, simply using steel insert fittings underground with worm clamps to interface to the black steel pipe in the garage. I am not planning on doing this, since it wont be code, but is there really that much hazard involved if a- It does not leak and b-no one hits it with a shovel

[Bob Wheatley]

Your friend is a fool and yes, there are multiple "hazards". From chemical decomposition to expansion and contraction and structural integrity. In simple terms, let's not put a 15" tire on a 14" rim......Okay?

Bob Wheatley

[warrenshudson]

hehe ok. Thanks. How long will it take for black poly pipe to decompose and start to leak?

[Andrew]