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I had my local gas service company disconnect my house from the gas service line. They offered to remove the meter for me and cap the house intake pipe, which I accepted. So to be clear, the service meter has been removed from my property and the house intake pipe is capped.

I didn't turn off any pilot lights and I tried running my gas dryer yesterday (it didn't warm up). Because I didn't turn off the pilot lights, my working reasoning is that any remaining gas pressure should have been relieved by the pilot lights burning out over the past several weeks.

I need to remove a significant chunk of gas pipe to proceed with another project on the house. I realize that the most reasonable thing to do is hire a contractor to do this for me. But I'd rather not pay someone to do it if it's a reasonably safe thing for me to do myself. With that in mind, I have a few questions for anyone who might be more knowledgeable about this stuff than me.

  • Is the reasoning that there is no excess pressure in my capped natural gas pipe sound?
  • Is it safe to remove the pipe one section at a time moving from appliance caps toward the service intake end? Is there a recommended procedure? (eg, cap each section as you go at both ends)
  • Is there a generally safe venting procedure to let out excess unpressurized gas?
  • Are there any pipe handling / disposal best practices for used gas pipe? - My anxious self imagines all kinds of unsafe impurities or additives remaining in the pipe even after the gas is properly vented.
  • Anything I should be asking? (aside from introspection around what makes me so stubborn that i don't want to hire an experienced person to do this)
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    There is likely to still be gas in the pipes, even if not at above-atmospheric pressure. It may very well be mixed with air, meaning it has explosive potential if ignited by a spark etc. I believe the correct procedure would be to first flush out any gas from the pipes (perhaps with nitrogen) but I am no expert. I wouldn't expect any unsafe deposits in the old pipe, maybe some rust and/or water.
    – Armand
    Jun 18, 2023 at 18:58
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    Perhaps rent an air compressor and let it run for a while. Taking care to mot create a spark. Or call a gas fitter, ask him for an estimate and quizz him on his process Jun 18, 2023 at 21:02
  • Flushing sounds like a good idea. I believe natural gas is lighter than air and would be pushed out of a high vent at the top if i used the air compressor at the appliance end. Thanks for the suggestion! Jun 18, 2023 at 21:37

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Any pressure in the pipes disappeared instantly when the meter was removed. Disconnected gas piping poses no special hazards, it can be removed and disposed of just like any other steel piping. Any trivial amounts of gas left inside the pipes would be too small to be of any concern. In the construction trades, old gas piping is routinely cut up with power saws and cutting wheels which generate a great deal of heat and sparks without any special precautions taken.

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  • Remove the cap and let it set for a while so any remaining gas can dissipate from the pipe. If you want you can push an hose in it as far as you can get it and blow air in or from the other end of the pipe.
    – Gil
    Jun 18, 2023 at 21:16
  • @Gil Weeks on, there's no remaining gas in the pipe. It diffused out the open pilots a long time ago.
    – Ecnerwal
    Jun 18, 2023 at 23:42
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Normal atmosphere is at 15 PSI. Most pressures are measured relative to that. If you dive down in water, your pressure increases at about 1 PSI per 2 feet of dive. This becomes an expression called "water column" - a 50 foot water column is 25 PSI. Measuring inches or feet of water column is a way to measure low pressures that are too small to wield as PSI numbers.

People ask "what pressure is natural gas in my home? 100 PSI? 750 PSI? None of that - it is about 6” of water column, or 0.25 PSI above atmospheric. That's enough.

So the amount of gas remaining in the pipe is inconsequential. Even if it was fully pressurized at 0.25 PSI it would be negligible.

Natural gas is stoichiometric at 10:1 by volume natural gas to air. Unless it is somewhere near that ratio, it will not burn. A 3/4” pipe vs the volume of air in the room is nowhere near that ratio.

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When we replaced the gas furnace/appliances that came with our new home we had the contractor remove every single gas pipe from the house at the same time, but also were told if we didn't that a plumber could remove these for a nominal fee. FYI you can also request the gas company to "retire the line" which removes the gas lines completely off your property rather than simply capping it. It is something they own so they should do this for free (ours was no charge - they did 95% of the work out in the street and spent 10 minutes pulling out the actual meter from our yard). This is especially important if you live in an earthquake zone, as natural gas lines very often leak and break in significant events, creating an obviously dangerous environment that compounds the situation after a natural disaster. Note - we also sold our gas appliances on Craigslist for a deal which allowed us to use that $$ towards our heat pump project :)

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