gas pipe question

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Master Brian, Nov 24, 2008.

  1. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    The line coming into my house from the meter is currently about 1 1/4" - 1 1/2" black pipe. The other day I was at my sisters and noticed her line, which looked like closer 2"+ galvanized pipe. This made me curious.

    I am looking at having the line from where it comes into my house to where it feeds the furnace replaced. Can I step up from the 1 1/4" line that is at the inside of my wall and go up to 2" pipe, then reduce back down when it gets to the appliance?

    Basically, it would leave the meter as 1 1/4" line, enter the house, then step up to 2" line for the main trunk. Is there a problem with this?

    I just want some opinions before I start calling people to come out.

    Maybe 1 1/4" line is enough, but all it currently services is a stove, furnace and hot water. In the future I'm looking at installing up to 3 gas fireplaces, a 2nd furnace or a boiler. At that time, I would upgrade the meter and the line coming into the houe, if need be. Maybe 1 1/4" line would service all of those items?...... I just don't want someone saying it's ok, because I ask, then having troubles, or someone saying, don't worry about it and later on I add the items and have to replace the line again....
  2. 1 1/4 is a big line

    that 1 1/4 line is more than big enough for about anything
    you are gonna throw at it....

    most homes only have a 1 inch line with normal pressure in ounces

    jumping up to 2 inch is over-kill
    ...
  3. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Ok, I may have answered some of my own questions by finding this site.

    Looks like since I would only be going a maximum of 20' before it starts feeding the 1st items in my list 1-1/4" pipe would be more than sufficient. In fact, my range will need to "t" off within about 2-3' of entering the house, so it actually stops dropping sooner.

    I figure everything I have will be no more than 500CFH. That is probably on the very high side, but again, I don't want to have to replace what I replace and I want to know that whatever someone does is sufficient for whatever needs arise in the future....
  4. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Yeah, I just saw that. It never seems to fail, that as soon as I finally post to a forum, the answer seems to jump out from somewhere else. Thanks for the reply though.

    Just out of curiousity, does it hurt to increase the diameter of the pipe from small to big back to small?

    I know gas is very low pressure and I am actually thrilled I found the site I linked to because I have been tearing out gas line that was unhooked, yet still running through the house even though I know I'll likely be running new line later on. I just didn't trust the old stuff and now I'm seeing that it wouldn't have been large enough to handle some of the future possible loads. Lots of 1/2" line that might some day feed a 2nd floor furnace and gas stove. From what I see the 1/2" would have been fine for the stove, but not the furnace at about 20' run.
  5. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    Whoa there fellas. Without knowing what line pressure is at the street you can't make any valid recomendations at this time.
  6. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Where do I find that? Gas company?

    I have always been told natural gas is about 4-6psi. The one plumber who came out never mentioned pressure either, but again, I just asked for a quote on moving the line over about 1-2' and running all new line.
  7. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    The gas company yes. We have two very separate pressure zones in Rochester. There is high pressure on one side of town running almost 20 lbs in the street and less than 2 lbs on the other end of town. The mains on the low side are considerably larger in diameter. It is not unusual for 1 1/4 and 2" feeders to run off those low pressure mains.
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,293
    Location:
    Cave Creek, Arizona
    gas

    The gas line charts do not work that way. You add up the total continuous length of the pipe to the farthest outlet. Then you use the column under that length for ALL your sizes as you make connections to it. You do not use the 25' column for the first piece, then the 10' one for the second, and so on.
  9. Bob2

    Bob2 New Member

    Messages:
    5
    Since I don't know, I'll ask.
    Why black pipe for gas? Most all gas lines seem to be black pipe. Is there some chemical thing with galvanized and gas? Or maybe the tin in galv. gets air borne?
    Bob
  10. sixlashes

    sixlashes Plumber in Previous Life

    Messages:
    83
    Location:
    Pensacola. FL
    Either galvanized or black iron work well for gas. Galv is usually more expensive. I have run a lot of galv, but exponentially more in black iron.

    Nowadays intermediate pressure copper is used more and more with regulators at every fixture. I don't like/trust the regulators in the house at every fixture.
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