galvanized versus black


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Old 10-06-06, 10:41 AM
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galvanized versus black

I have been reading old threads about this issue and I want to check that I understand your recommendation.

I need to move my gas stove and no one at Home Depot could tell me which type of pipe to use ( have natural gas). The pipes now are black, but many of the fittings (els,ts, etc) are galvanized.

Is it okay to mix them? No leaks now, but I will be finishing the basement ceiling so I want to get them changed now if they need to be.

It seems from other threads that using black is safer for natural gas, but that galv is also used in certain areas. But what about combining them? I know there are issues about different metals in contact with each other. I just don't know if they apply here.
 
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Old 10-06-06, 12:26 PM
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It's my understanding that "black pipe" is only used for Natural Gas. Galvanized is good for anything (including natural gas), though I wouldn't use it for water due to corrosion.

Black pipe rusts, so shouldn't be used where it is exposed to the elements.
 
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Old 10-06-06, 02:12 PM
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The problem with galvanized pipe and fittings is that the galvanized coating breaks off and plugs the burner and control valve orfices. Codes vary on the use of galvanized for gas lines. Florida (parts of it) allow it for gas. Many States do not allow it. Any fixture using gas should have a "drip-leg" to catch any particles that get into the line.
 
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Old 10-06-06, 03:43 PM
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Thanks for the info. Is there a problem with mixing the two?
 
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Old 10-07-06, 05:39 AM
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Originally Posted by rambelmont
Thanks for the info. Is there a problem with mixing the two?
I know if you mix the two the zinc will depleat faster. Perhaps this will cause more flaking.

A couple of years ago I had trouble with a heater and the problem was crud in the orifice. Cleaned it and checked the trap in the line. I was amazed at how much rust had accumalted in it it. Im hard pressed to say which would be worst rust or zinc flakes. Go with the code, check with your NG supplier. I understand they have Cu and plastic lines now that may be better than either.

Code in Fl is galvanized code in NC is black. I can see why they would be different. Black pipe wouldnt last long in Fl. Down there corrosion from the outside would probably be the main concern. I know, wife has a house down there and the furnace was plumbed for LP using black pipe. Good thing the house is built on a sand hill. It was easy to dig up.
 
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Old 10-08-06, 09:17 AM
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Thanks for your help. I will check the "drip legs" to see if there are flakes. Unless I find a lot of flakes, I will leave the gal fittings where they are.
 
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Old 10-08-06, 11:37 AM
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" I will be finishing the basement ceiling so I want to get them changed now if they need to be."

I'd check to see if you will be allowed -by code- to enclose your gasline in the ceiling. Locally, code allowed me to pipe NG thru a wall (no joints within the wall) but not enclose any portion of gas piping with joints. Mixing of black iron and galvanized is okay where I live but your local code is what you should follow.
 
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Old 10-08-06, 05:40 PM
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Yikes! Is that restriction (not enclosing gasline) common for other areas too?

My furnace and HWH are 30 ft from the incoming gas line and on the other side of the house -- need a minimum of 3 els and 2 couplings to get the gas to them.
 
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Old 10-10-06, 03:36 PM
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You are right as far as your experience went. I spoke to the head plumbing inspector today, and it is true that you cannot have fittings in a SOLID wall/floor/ceiling -- meaning concrete, masonry, etc.-- without a chase. But it is perfectly okay to have fittings in a drywalled ceiling.

Thanks for alerting me to this difference-- now I will know the rules.
 
 

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