Sizing a \"marginal\" gas line

Ron Gillen

Wrong table 1200' is for propane. 1/2" black is 450' at 1" W.C. pressure drop. Damn bi-focals.

Andy Stern

Sizing a \"marginal\" gas line

Hello and sure could use some advice... I need to install a 28,000 BTU gas heater that will require running black iron piping from the end of a 1-inch gas line in the basement which currently feeds a clothes dryer and a small log set. I can extend the pipeline another 20 feet with iron pipe (say 1/2-inch)to to the edge of the house where I can then go vertically in a covenient stud cavity but would like to use coiled copper ("L")for ease of installation (I think iron is out of the question) and also to avoid joints in the wall for the distance of 20 feet to the 3rd floor. From there, I need to go another 20 feet to the heater. The problem is I don't know if 1/2-inch copper will deliver 28,000 BTU (which I think is about 28 CFH). I think if was all 1/2" black iron there would be not problem, but I have that 20 feet of copper in the middle. 1/2 inch black iron has way more carrying capacity than 1/2-inch copper. Damn if I know why.

Thanks...
Andy

Ron Gillen

Not marginal at all

If you have the 28,000 available at the I" connection. You can run 1200 feet of I/2" Sch. 40 black pipe, 150 feet of I/2" O.D. copper or 500 feet of 5/8" O.D. copper. (Canadian Code)

bruce_21

Think about keeping that copper, if you use it, protected from future nails being driven to hang pictures, cabinets, who knows what, long after the pipe's location is forgotten. Its really easy to puncture copper and create a bomb. Check with your building inspector on the local code requirements.

I'd go with the black steel pipe, for safety's sake. It is not all that difficult to get 1/2" black pipe into a wall cavity. Use two pieces and cut a slot in the drywall, drill your holes and assemble it with a coupling. Since you'll have at least one buried fitting you'll need to pressure test the pipe before using it. 5psi with a guage the shows 1/10's of a pound held with no drop for 1 to 24 hrs depending on your local code. Safety is very important with gas.

jim lockard

huh

1200 feet?Must be powerful gas up there

scrook_2

1/2\" pipe vs 1/2\" copper

"1/2 inch black iron has way more carrying capacity than 1/2-inch copper. Damn if I know why"

1/2" trade size Sch 40 blk iron has an ID of .622"

1/2" trade size (5/8" OD) type K copper has an ID of .527"

also: 1/2" OD type K (3/8" ID) is only .402" ID

Since area goes with the square of the diameter, (and I care only about the ratios of the areas, not the actual areas, for comparison purposes) dividing (.527")^2/(.622")^2 = 0.72 so the copper has a little less than 3/4th the capacity.

If you meant 1/2" OD K instead, it's even worse, the 1/2" OD has about .42 times the capacity.

I assumed you meant K coil, not L coil by the way. Just curious: are planning on brazing the end fittings or on using flare fittings?

Andy Stern

Thanks for the help and advice. I decided that iron pipe makes more sense to bury in the wall froma long term safety issue point of view. I'll just need to do some patching. I have "balloon framing" so it makes it that much easier (except for the wife issues).

Andy

Don \"Grumpy\" Walsh

an alternative idea?

Have you thought of using a product like WardFlex?

chris_93

leave gas piping to the pros

I think you should leave the piping to the professionals. Being a licensed master plumber for 20 years, There are certains things that shouldn't be attepmted by an unqualified person.
Think of the safety of yourself, your family and possibly your neighbors if there was a problem and worst case scenario an explosion. Who are you going to blame?

Would you repair a commercial airplane engine if you were uncertain about a few things? I know i wouldn't..

I'm all for DIY's, because nowadays everything costs an arm and a leg. Save some money by opening the walls and getting the house ready to be piped. I would definitely charge less if all the "demo work" was done, and i could just install the pipe.
Food for thought. Good Luck..

Unknown

Good place I found...

http://www.engineeringtoolbox.com/natural-gas-pipe-sizing-d_826.html