sizing gas pipe

SNC · 12-10-2008, 02:47 PM

I have an 80 year old house, once ran on coal, then oil now it runs on natural gas.
For some reason who ever ran the pipe put a tee at the meter, in the basement near the front of the house. They ran two lines towards the rear. One is 3/4 pipe which branches into two 1/2 lines. One the the water heater, and the other to the kitchen, there was a 3rd to the dryer but I took that out and bought an electric dryer.
The other line 1" pipe runs about 20 feet then turns into 1/2 inch about 5 feet from the boiler. The boiler is 100,000 btu i think.
The first line to the kitchen is about 35 feet long.

My question is do i need this 1" pipe ? Seems to me 3/4 would be more than enough for the boiler.
Im asking because I am putting in a new boiler, a Prestige 110. I am relocating the boiler and want to eliminate the extra pipe, but since it is a 20' section I figure I will just take it all out and put in all new pipe on that leg.
What do you think?

SNC · 12-10-2008, 03:48 PM

according to this http://www.ci.newark.ca.us/externals...9224aef4dd.pdf

the 1" pipe is over kill.

**Termite** · 12-10-2008, 05:16 PM

I can help, but need a bit more info.

1) Need the btu/h input rating for each gas-fired appliance.
2) A pipe layout diagram showing appliances and pipe distance would help make this easy.
3) Need the distance (in pipe) from the meter to the farthest gas appliance in the house, even if you're not working on it. We use that distance to size every pipe in the home. Your city is sizing based on the IFGC code, which I know pretty well.
4) Describe how the two pipes are coming off the meter. Does one T off the other right at the meter or a few feet away from it?

For what it is worth, 1" pipe can handle 320000 btu/h's at a maximum length of 35'.

SNC · 12-10-2008, 08:33 PM

Quote:

Originally Posted by thekctermite

I can help, but need a bit more info.

1) Need the btu/h input rating for each gas-fired appliance.
2) A pipe layout diagram showing appliances and pipe distance would help make this easy.
3) Need the distance (in pipe) from the meter to the farthest gas appliance in the house, even if you're not working on it. We use that distance to size every pipe in the home. Your city is sizing based on the IFGC code, which I know pretty well.
4) Describe how the two pipes are coming off the meter. Does one T off the other right at the meter or a few feet away from it?

For what it is worth, 1" pipe can handle 320000 btu/h's at a maximum length of 35'.

I have about 1' out of the meter to the first tee.

line 1 is 21' of 1" pipe then 5' of 1/2" pipe to the boiler,110,000 btu. This line I am going to redo it will be about 5' shorter and 3/4 pipe.

line 2 from that tee at the meter is 19 1/2 feet of 3/4 pipe, at 19' it tees off a 1/2 pipe 10' + a 3' flex line to a 40,000 btu water heater.

the same 3/4 pipe at 19 1/2' turns to 1/2" pipe and continues for 20' + a 3' flex line to the kitchen stove that I figure is about 40,000 btu with all top burnners going.

so the longest run is 41 1/2 feet first half is 3/4 senond half is 1/2 BUT the first foot out of the meter is 1/2"

i hope this makes sence.

the range I dont know the btu i would guess 60 -70,000 btu