OT: Black pipe usage for propane line to grill?


Greetings,
About 3 years ago I installed a supply line from my home propane system to my propane grill located on my wooden deck (obligatory wood reference ;-)) utilizing black pipe and Oatey pipe joint compound. A few days ago I walked out on the deck and immediately noticed the tell-tale odor of propane. First thing I checked was my grill thinking I had left it on, but it was not. next, out came the squirt bottle of soapy water and I found small bubbles being produced at 2 of the joints in the pipe. This pipe had not been touched or moved in the 3 years it has been in place, so I am not sure what caused the joints to leak. My question is should I use something else to reseal the joints? Or just take the assembly apart, clean the threads and reapply pipe joint compound and reseal? I assume (there is that word) that just re-tightening the joint is probably not the best option. Do these type of joints need any periodic maintenance, or is it just Murphy rearing his ugly head? (since the leak was detected, I did shut off the supply line, don't want someone lighting the grill and getting more than they bargained for ;-)
TIA
-George-
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I'm not an expert on this, but I don't think plain black pipe is the proper material. My home propane was piped using copper tubing.
http://www.co.larimer.co.us/building/liquid_propane.htm
Materials allowed for yard piping include copper, PE (only pipe specifically approved for exterior buried piping systems may be used) and factory machine applied coated/wrapped black pipe with the joints of the black pipe wrapped with ten mill tape which is half lapped and double wrapped
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I ran the pipe from a connection that the home builder supplied on the back of my house. The black pipe is a total of about 10-12 feet, terminating to a propane approved hose (purchased at my local grill dealer) the hose then goes from the black pipe to the grill. Sorry, I should have been more clear in my OP.
Thanks
-George-

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As for the OP, be sure the gas is off disassemble the pipe, clean the threads, and reassemble using a good pipe thread dope. On the job we use Rectorseal with Teflon. Don't be afraid to tighten it good. Turn the gas back on and check for leaks using dish soap and water. Greg
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Edwin Pawlowski wrote:

That link gets a "connection refused". Generally speaking steel pipe is preferred for gas. Some folks I know down in New Haven damned near blew up their building when a copper gas pipe broke--the gas company wouldn't turn the gas back on until the inspector approved the gas piping, and he made them rip out _all_ the copper and replace it with black pipe, on a three story building in the dead of winter.
--
--John
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Natural gas and propane have some different rules. Here in Putnam a house did blow up when the gas company inspector broke a plastic line with his probe while looking for a leak. He made it worse and it took out the house and did major damage to the ones on each side of it.
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Unless the pipe is totally exposed to the weather, and the rust and corrosion build-up is VERY obvious, you should not experience any problems. However, most people don't tighten NPT threaded joints sufficiently. You should be able to turn in about 3-1/2 turns by hand, and you should tighten an additional 1-1/2 to 2 full turns with a wrench. Additionally, teflon tape is preferred over pipe joint compound (it never hardens).

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Bruce T wrote:

Using teflon tape on combustion piping is an absolute no-no because sooner or later a bit of teflon tape will break loose and find it's way to the nearest orifice where it will plug it.
OTOH, teflon paste works quite well on combustion plumbing.
Lew
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There is a tape designed specifically for gas fittings.
Max D.
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You would likely be better off posting to A.H.R. but as a start ....
The right move was to turn off the supply! You have a severe hazard that needs to be fixed before ever turning the supply on again.
I can't make any more recommendation than to consult or even better, hire a pipe fitter who is gas certified and make the installation compliant safe and to reg's. I am guessing a complete disassembly with a rebuild using properly rated materials and methods.
I don't believe the "Oatey pipe joint compound" you used is 'gas' rated and likely the major cause for the failure you are seeing. Any 'black iron' piping that is exposed to weather must be properly coated with a protective layer of rust inhibiting paint sealer and usually is done on site *after* all pressure leak-down tests are satisfactory.
Please, consult with a properly licensed expert. There could be well be regulatory items limiting what you can DIY but regardless this is not an area for trial and error.
Ed
George Gibeau wrote:

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You're quite right there. Contrary to popular belief, pipe joint compound is not meant to seal the joint. It's primary function is to lubricate the threads so that they can be screwed together tightly enough to seal.

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