Thread: Galv and Cast

Anyone have a problem with Galvanized and black iron joined togeather for natural gas line? Galvanized corners and black iron straight sections

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Originally Posted by wayne soper

Anyone have a problem with Galvanized and cast iron for natural gas line?

I see galvanized regularly. Cast iron? Never. How would you seal it? Do you mean black iron pipe?

Yes Black Iron, Sorry,

Black pipe is for gas. Galvanized for water. It is common to see some galvanized fittings or pipe used in gas runs. Contractor runs short etc. However, galvanized is not approved for use with natural gas, nor is it considered good workmanship.
suggest write it up.

I'm not certified for plumbing codes, but I asked my friend who is a plumber this question several years ago, and he said it made no difference. Galvanized costs more, so you don't see it very often for indoor use.

Are you sure about your statement that it is not approved for use with natural gas?

According to Code Check galvanized is okay, the IRC reference listed is 2414.4.2. I've read on a different forum that the newer galvanized pipe is electrostatically coated rather that dipped, so the coating doesn't flake off and clog the lines. Galvanized is probably a better choice for outdoors, especially anywhere near salt spray. I sometimes see a galv. coupler used indoors, like Marcus said, maybe the plumber ran short.

Galvanized is okay for gas, besides, if the galvanized does flake off, there is a sediment trap ... isn't there?

Galvanized piping on a gas system is a repair item on my report due to possible flaking of the inside coating of the pipe. I don't offer a code refernce...only some stuck gas valve references. Another plumber can say I am wrong....in writing.

Muni insp routinely flag it and require change out up here. I'll check our code to see if/what it says. I just know for now it has always been a no-no.

In my past life as an engineer ,we did some fact finding black pipe and galv pipe are the same size. Diffence is galv While threading galv pipe the die does wears out faster

2006 NFPA 54, National Gas Code allows the use of the following materials for gas piping systems.

1. ANSI/ASME B36. - Steel & wrought-iron
2. ASTM A53 - Steel Black Iron & Hot-Dipped Zinc Coated seamless and welded.
3. ASTM A106 - Seamless carbon steel for high temperature service.
4. Copper and brass pipe - (can't use if gas contains more than .3 grains of hydrogen sulfide per 100scf of gas)
5. ASTM B 241 - Aluminum alloy (must be marked for gas use) and has specific installation requirements.
6. ANSI LC 1/CSA 6.26 - Corrugated Stainless steel.
7. ASTM D 2513 - Thermo-plastic - (for outdoor and underground use only)

If you write it up as a problem, you are incorrect. You should not tell your clients something that is not true.

--- Only the "Facts Jack" ---

Did not write it up as a problem, Thanks for all the replies. Wayne