Propane piping

[considerations]

I thought I saw a discussion on this forume about the underground piping from a propane tank to the house, and the materials that could be used for that purpose.  Now I cannot find it.

I seem to remember that some areas allow black iron piping, some copper, and some even use flexible tubing conduited in PVC.  I'm in Washington state, would anyone care to steer me to the propane thread, or comment on the techniques and materials allowed in this state?

[glenn kangiser]

Here I used Fletcher coat pipe below ground with all joints taped with 10 mil tape where the metal was exposed to the ground at each joint.  That is a very common way to do it around here.  The riser can also be taped.  I'm not sure what other options are allowed by code.

There was some discussion on Christina's Georgia house thread.

http://countryplans.com/smf/index.php?topic=2991.msg43396#msg43396

In the ground, here, electrolysis eats copper within a year or so.  Not even used for water.

[ScottA]

I recommend poly pipe (HDPE). Its the industry standard for underground fuel gases. The pipe is plastic but the risers are coated steel. Parts can be purchaced for mechanical joints or fusion weld. Mechanical would be best for the homeowner since you don't need special tools. It's really tough stuff.

[Redoverfarm]

Common practice here is the "yellow" plastic line to the regulator then once inside black iron pipe.  At least that is what I will be doing.  Generally the person setting up your propane tank will run the line to the regulator and it is up to the homeowner to run it inside the house.  This is one area that I will probably contract out.  Too much of an investment to buy a die set to thread the ends.  A contractor will buy the pipe in bulk length then cut and thread as desired for the various outlets. 

[FrankInWI]

they set my tank and ran the line to the garage when I was away....but what I see is copper tubing.  that's in central wisconsin.   I have a lot of sand, not rocky, not clay.  Many many tanks in the area, think this is the normal way around here.

[desdawg]

What Scott said, the yellow polyethelene gasline is what we used for direct burial. It comes in rolls and for the homowner the mechanical fittings would be the best. The heat fusion equipment is too expensive to purchase for a one time use. The socket fusion equipment heats us the inside of the fitting and the outside of the pipe to 500 degrees and welds them together but compression type fittings are available. You have to dig a little deeper for the PE pipe as it is required to have 18" of cover whereas the steel pipe only requires 12" of cover. Also it is a good idea in rocky soil to bed the pipe in sand to protect it from being rubbed by rocks as the soil expands and contracts with temperature changes. Your inspector may require this.
I bought a pipe threading set at Harbor Freight some years ago, up to 1" pipe, very inexpensive but adequate for occasional use. I wouldn't want to use it to make a living with but to thread a piece of pipe now and again (homeowner style) it has held up very well. Of course then you need a pipe vise and a pipe cutter. For larger sizes you would probably want a power threader or a membership at the gym, not that it can't be done but it requires some strength.