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Gas pipe ratings have a certain amount of BTU with a certain pressure drop. Looking at https://www.gastite.com/downloads/pdfs/gastite_sizing_tables_natural_gas.pdf for example, it says in table 7-6 that 1-1/4 flex pipe can carry 456 CFH on a 150 ft run with a 4" W.C. pressure drop, but in table 7-1, that same pipe can only carry 164 CFH if the pressure drop needs to be at most 0.5" W.C.

Is the following a safe / correct understanding of how the pressure drop stuff works?

Let's say all my appliances connected to the meter are rated a minimum pressure of 4" W.C. and maximum of 10.5" WC or higher, but I need to sustain a 4" W.C. pressure drop in order to carry the needed CFH over a particular run. If I'm on 7" W.C. now, then that won't work because it'd put me at 3" W.C. (7" minus 4" = 3") which is below the minimum of the appliances. Therefore to solve for this, I could have the gas company increase my regulator pressure at the meter to 10" W.C. since that would still be below the max rating for all appliances, and then it would allow for this large of a drop since 10" - 4" = 6" W.C. which is still above the minimum.

I don't know what I don't know so wanted to make sure there are no pitfalls (e.g. perhaps pressure fluctuates so I shouldn't get too close to the limit or something), or perhaps I don't understand the pressure drop concept correctly at all.

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  • Do you have a 150 foot run between the meter and appliances? Seems to be long for a house.
    – crip659
    Aug 3, 2022 at 14:20
  • @crip659 the longest thing in consideration here is a natural gas fire pit in the back yard and the distance to that is about 180ft
    – g491
    Aug 3, 2022 at 15:36

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Contact your gas company, changing pressures etc places a big liability on you. You pay them take advantage of it and see what they tell you. It will probably be done at no cost and you can sleep at night instead of counting potential gas leaks.

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  • Yeah I reached out to them to see if this is something they offer and could be involved in when swapping the meter anyways.
    – g491
    Aug 3, 2022 at 23:48

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