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  1. #1
    Join Date
    Jul 2004
    Posts
    68
    Looking for info to size a natural gas line with 3 appliances. two at 125,000btu and one at 204,000 btu's.

  2. #2
    Join Date
    Jul 2004
    Posts
    3
    how long is line, what pressure, and which fuel, nat. or propane? Or go to your International fuel gas code book and check.

  3. #3
    Join Date
    Apr 2005
    Location
    where the beer flows like wine
    Posts
    2,871
    inch and a half main,3/4 branches to the units. check NFPA-54.

  4. #4
    Join Date
    Aug 2003
    Posts
    1,311
    how many elbows, t's, forty five's and the like.

    Uniform plumbing code book.

  5. #5
    Join Date
    Jul 2002
    Location
    Slacking off right now
    Posts
    7,546
    with the codes I have used they have a fitting allowance of 20 % built in in the low pressure to 2 psi charts as I remember

    1 pressure are you using 7" or 2 psi or 5 psi

    2 if high pressure you size for the high pressurse to the service regulator as one load eg 100ft 454000 btu's

    then you size the low pressure after the regulator to the indivual loads and lines
    It should be all in your gas code book

    if low pressure then longest measured run is the tablwe you use eg if the longest pipe rune is to the 204000 load then size according to this It should all be in your books and tables
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  6. #6
    Join Date
    Jan 2005
    Location
    Area 51
    Posts
    984
    You need to size it by CFH (cubic feet per hour) not BTUH. if the appiance is rated at 100,000 BTUH and the gas is rated at 1000 BTUH the CFH is 100 with that number you can look in th Fuel gas code book and get the size of gas pipe you need with the existing pressure drop an length of the pipe run.
    "Paddle faster, I hear banjo music"

  7. #7
    Join Date
    Jul 2001
    Posts
    3,112
    2" pipe to every appliance, then using a bell reducer from 2" to whatever inlet size is to the appliance. This will reduce any volumn loss and should work okay.

  8. #8
    Join Date
    Mar 2005
    Location
    South/West of Quebec in the other part of Canada
    Posts
    2,331
    tonymjr:

    listen to mech4 , read and apply the tables..

    [Edited by key on 10-30-2005 at 05:52 AM]

  9. #9

    Natural Gas Pipe sizing for outdoor appliances

    Guys - I'm jumping in here because I have a very similar situation.

    I need to run a new line (branching off close to the meter) that will provide gas for an outdoor grill (58,000 BTU), outdoor dual burner (30,000 BTU) and a gas fireplace (approx 25,000 BTU, guess as I have not purchased this piece yet). The line will run 30 feet in house, then go through the foundation. From foundation will split into two separate directions - one for the Grill / Side burner (same location, about 40 feet from foundation) and the other for the gas fireplace (different spot, also about 40 feet from foundation - actually, this second line will go about 25 feet at 18" below grade, then run up through an old ash clean-out to a second floor fireplace that I will convert from wood to gas via an insert).

    I've been checking flow charts, so for the first 30 feet of the line which are along the basement ceiling, it looks like I need to use 1" black pipe (total length to each appliance is still 70-80 feet, which the chart says 1" pipe over 80 feet will provide 193CFH). But from the foundation, not sure what sizes to branch to. Can I drop down to 3/4" and if so, how does that affect my flows (charts don't talk about two different pipe sizes for a given run).

    I am thinking I will use copper with compression fittings outside the house. Do I run two separate lines to the grill and side-burner, and a third to the gas fireplace? Or do I run one larger line to grill/burner combo and split it out close to them, plus a second small line to the fireplace?

    Thanks,
    mvd7

  10. #10
    Join Date
    Dec 2007
    Location
    Soudern Kaliphonistan
    Posts
    282
    Quote Originally Posted by mvd7 View Post
    Guys - I'm jumping in here because I have a very similar situation.

    I need to run a new line (branching off close to the meter) that will provide gas for an outdoor grill (58,000 BTU), outdoor dual burner (30,000 BTU) and a gas fireplace (approx 25,000 BTU, guess as I have not purchased this piece yet). The line will run 30 feet in house, then go through the foundation. From foundation will split into two separate directions - one for the Grill / Side burner (same location, about 40 feet from foundation) and the other for the gas fireplace (different spot, also about 40 feet from foundation - actually, this second line will go about 25 feet at 18" below grade, then run up through an old ash clean-out to a second floor fireplace that I will convert from wood to gas via an insert).

    I've been checking flow charts, so for the first 30 feet of the line which are along the basement ceiling, it looks like I need to use 1" black pipe (total length to each appliance is still 70-80 feet, which the chart says 1" pipe over 80 feet will provide 193CFH). But from the foundation, not sure what sizes to branch to. Can I drop down to 3/4" and if so, how does that affect my flows (charts don't talk about two different pipe sizes for a given run).

    I am thinking I will use copper with compression fittings outside the house. Do I run two separate lines to the grill and side-burner, and a third to the gas fireplace? Or do I run one larger line to grill/burner combo and split it out close to them, plus a second small line to the fireplace?

    Thanks,
    mvd7
    Youre going to run nat gas thru copper?

  11. #11
    Join Date
    Mar 2004
    Location
    Austin, Texas
    Posts
    1,967
    Copper is allowed for natural gas in some locations. But where I am the gas corrodes the inside of the copper.

    Look up the gas line sizing in your code book. The NFG, mechanical, and plumbing all have the information. Some even have an example worked out. Once you know how to use the sizing charts, its up to you to figure out whether to run multiple lines or just one.
    If "I have always done it this way" is a good reason to do it again, how many times do I have to do something wrong - before it becomes right?

  12. #12
    Join Date
    Dec 2007
    Location
    Midwest
    Posts
    638
    Lets say your at about fifty feet before the first take off on the gas line, lets also say the first appliance is the 204 load then assume that you are running a pressure less than 1.5 PSI, you will need 1 1/4 to the first applaince then branch off with a 1" pipe. Then continue the main run with 1" to the next appliance and branch off to the next with 3/4" pipe to third.

  13. #13

    Natural Gas Pipe sizing for outdoor appliances

    Thanks for the info -

    I did check with my local plumbing supply shop (owner is licensed plumber) and my options for outdoors (18" under ground) are either Galvanized Steel or copper with compression fittings for my area.

    I like the idea of running my steel pipe for the first 60 feet (total CFH is only 153 for my three appliances, so 1" should be good, according to the charts). Then I'll split off with copper - one 3/4" 15 foot line to the two that are in same area (total of 80 CFH for these), then break out to two 1/2" copper fittings for the connections, and one 3/4" 22 foot line to the fireplace that is 73 CFH. (Distance from meter to all three appliances is about 80 feet).

    One last question - is it generally acceptable to have gas lines, water lines and electric (double protected - UL rated wire running inside a grey PVC pipe) close to each other under ground? I want to put all my runs in the same proximity when burying them...


    Thanks,
    mvd7

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