Sweep's Library - Gas Plumbing Sizing Chart

Gas Pipe Sizing for Iron Pipe at standard gas pressure

This chart will give you the size of the gas supply pipe needed, based upon the BTU/HR usage of the gas appliance(s) and the length of pipe used.

Example:
We're plumbing the gas supply for a 60,000btu (60k) furnace and we have to go 40 feet.
Read across the top of the chart until you come to the 40 ft. column
Read down the 40 ft. column until you come to the first number larger than 60k
The Pipe size column tells you 1/2 inch pipe will make it (See 65k in red on the chart)

Pipe Size	Length Of Pipe In Feet
Pipe Size	10 ft.	20 ft.	30 ft.	40 ft.	50 ft.	60 ft.	70 ft.	80 ft.
3/8"	74k	50k	41k	35k	31k	28k	26k	24k
1/2"	135k	94k	75k	65k	57k	51k	47k	44k
3/4"	285k	195k	156k	133k	118k	108k	98k	92k
1"	533k	359k	292k	251k	220k	200k	184k	174k
1-1/4"	1076k	748k	605k	513k	451k	410k	379k	359k
1-1/2"	1640k	1128k	912k	779k	687k	625k	574k	543k

Gas Pipe Sizing for Iron Pipe at standard gas pressure

This chart will give you the size of the gas supply pipe needed, based upon the BTU/HR usage of the gas appliance(s) and the length of pipe used.

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