I have a gas line running to my outdoor hot tub water heater. When I first installed it 8 years ago I used black iron pipe because i heard that it was required. Lately I've noticed that it is heavily rusted where it is lying on the concrete. Can I replace it with galvanized? I get all sorts of answers from google. Engineman
IIRC it depends on the sulphur content of the natgas in your area . Have you considered blocking it up off the concrete so it's not in constant contact with the moisture that's causing the rust ?
"Terry Coombs" wrote in news:D9GNl.38961$ snipped-for-privacy@bignews7.bellsouth.net:
Ditto this. Stand it off with some pipe hangers. Don't use pressure treated lumber. Grey paint is the standard outdoor rust preventative for black gas pipe around here. Yellow paint if there is concern it might be confused for water or air.
Get it off the ground, clean it up, prime and paint it. Problem solved.
If you hear whistling from the gas pipes when the hot tub heater kicks on, do the CFM flow math. You might need to take it out and bump the pipe up a notch or two (1/2" up to 3/4" or 1") - and prime and paint it well as you replace it.
You don't want to use galvanized unless you really have to. Plumbers see galvanized pipe and they think "water"...
If it is buried, the pipe is supposed to be the green plastic coated black pipe, and you have to wrap all the joints and couplings with approved tape to seal out moisture and reduce rust. But this is above ground.
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NO - but you can cold galvanize it with a spray can of paint and zinc.
The metal inside the pipe is the issue, not outside. Derbs clogging the regulator was to be prevented.
Mart> I have a gas line running to my outdoor hot tub water heater. When I
Galvanized is usually Ixnayed because little bits may fall off and clog the jets/regulator.
A strong secondary issue is plumbers who think galvanized == H2O..
The question is, what are the codes in your area? In my area we use International Mechanical Code and it does allow the use of galvanized pipe for natural gas or propane. We can also run copper for natural gas. Your codes may differ. IIRC, according to IMC, black iron pipe less than 6 inches from the ground has to be treated as underground pipe, and properly coated. If you get the pipe over 6 inches off the ground painting is adequate. Below six inches the coatings need to be for underground pipe, and painting does not meet the requirement!. Again, your codes may be different! Now if it were my pipe, I would clean it well and paint it, and keep an eye on it. If it is pitted badly, I would replace it with galvanized, and paint any exposed threads. Greg
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