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1/2 Black Iron Gas Pipe Chart
- Thread starter cookster
- Start date
redsky49
Well-known member
Gas pipe sizing based on:
1. Maximum calculated total gas consumption
2. Length of pipe and fittings
3. Allowable pressure loss from source to appliance
4. Specific gravity of gas
You need to state the working pressures, etc.
Typical capacity for 1/2", for the utilities I am familiar with, are 100' of pipe = about 30,000 btuh, not 50,000.
Fittings all differ in pressure loss whether short or long radius ell, etc. Also there is a pressure drop across valves, unions, etc.
As always, offered only as opinion
1. Maximum calculated total gas consumption
2. Length of pipe and fittings
3. Allowable pressure loss from source to appliance
4. Specific gravity of gas
You need to state the working pressures, etc.
Typical capacity for 1/2", for the utilities I am familiar with, are 100' of pipe = about 30,000 btuh, not 50,000.
Fittings all differ in pressure loss whether short or long radius ell, etc. Also there is a pressure drop across valves, unions, etc.
As always, offered only as opinion
38 Special
Well-known member
50,000 is correct according to my table.
http://www.firelogs.com/GasLine.htm
60' will yeild 66,000 BTUs.
I figure 6' for elbows. Not sure where I got it, just what I have always used.
This assume a 7" system (White faced gas meter), if 2 pound system (red face meter), you can run a smaller line and put the regulator at the appliance end.
http://www.firelogs.com/GasLine.htm
60' will yeild 66,000 BTUs.
I figure 6' for elbows. Not sure where I got it, just what I have always used.
This assume a 7" system (White faced gas meter), if 2 pound system (red face meter), you can run a smaller line and put the regulator at the appliance end.
redsky49
Well-known member
50,000 is correct according to my table.
http://www.firelogs.com/GasLine.htm
60' will yeild 66,000 BTUs.
I figure 6' for elbows. Not sure where I got it, just what I have always used.
This assume a 7" system (White faced gas meter), if 2 pound system (red face meter), you can run a smaller line and put the regulator at the appliance end.
I don't mean to disparage 38 special, but I would suggest that an on-line "firelog" vendor's sizing chart may not be the best source, especially as no design conditions were stated on their chart.
My sources are from published data from reputable sources.
For example, 100 ft. of clean straight Sched. 40 black steel is good for 38 cubic feet of gas per hour at a pressure drop of 0.3" water, specific gravity of 0.60. This is from the ASHRAE Table 26, Fundamentals Handbook. Based on nominal heat values of 970 -1050 btu/cub.ft., that equals 36,860 - 39,900 btuh. Remember though that this is for a theoretical 100 ft. clean pipe with no turns or fittings.
Installed piping, with a moderate number of fittings, will typically fall into the 30,000 btuh range, and that is a number that may be safely used for most installations. By most installations, I am referring to a low pressure, after the meter system in the 5.5" - 7.0" range, with a 0.3" pressure drop per 100'.
If you have a very convoluted piping system you may wish to calculate the actual system pressure drop based on the fittings. Actual pressure drops for 1/2" steel pipe range from 0.21 for a union, to 4.2 equivalent feet for a screwed tee. Unless you have a complicated piping arrangement, this calculation generally isn't required.
Your best bet is to start with the gas utility and find out what the actual system values are for your particular application. Confirm any internet "advice", mine included, with your local utility and building authorities, as well as the manufacturer of the gas appliance you intend to use. If in doubt, consult an expert. Undersizing a gas line will frequently prevent an appliance from operating so you want to get it right the first time. And never forget the inherent danger from gas.
As always, offered only as opinion