I had to hook up a small electric water heater a few years ago and used
a combination of short-length galvinized and regular steel pipes and
tees near the tank, and used PEX feed lines to and from the tank.
In about 3 years the non-galvinized sections were very rust on the
outside, and really badly crudded-up on the inside, creating rusty water
if the hot water wasn't used for a few days (this is a small tank -
about 3 or 4 gallons). There was even some leaking of these pipes too.
I replaced everything with galvinized and no rust and no leaks for about
2-3 years now.
For a gas line, there is some water in natural gas - you're supposed to
put in a drop-trap line to catch the water before runs into your
appliance so the water can accumulate there. I'd be using galvinized
for that if it were me.
On Fri, 21 Jan 2011 21:19:12 -0800 (PST), Mikepier
Just check the local code, and go by that.
See if it's all black pipe now.
If I knew black pipe was code, I'd use black pipe.
I put a galvanized gas pipe run in my first house in Chicago when I
working in the basement. Had just re-piped all the water and had
plenty of galvanized left over.
Sometime later a gas worker was in and spotted it right off.
Think it was an appliance guy when I bought a new dryer.
He said, "You do that?"
I said "Yep."
"Why'd you use galvanized?"
"That's what I had."
He could see my pipe bench.
Nothing more was said.
Always assumed he asked because galvanized was more expensive and not
necessary. Who knows.
I don't know what code is here, but I put a new HW tank a couple years
ago, and had to replace a gas nipple with a longer one.
Used galvanized, didn't think anything of it.
I just looked and see a lot of galvanized Tees and 90's on the gas
piping that were already there.
Now I'm pretty sure I'll never check the code.
Local codes rule.
At one time it was prohibited in this area and now it is fine.
If you don't know the local code, I would find a black fitting somewhere.
I have used them in a pinch in the past and never experienced any of the
dour predictions I have seen expressed in this thread. I should add that I
own the same houses now that I did 20 years or more ago.
Please come visit http://www.househomerepair.com
I asked this question of my mechanical engineering mentor nearly ~35
He's long gone & I have mixed installations that has been in service
for over 30 years.
He's comment to me back in the 70's was........
"The myth that natural gas causes galvanizing to flake off is an old
wives tale that has debunked by testing, go ahead and use it"
Here is a link to pretty detailed thread on the subject, including
cites from the IRC.
a couple guys go back & forth but I'm putting my money on the IRC,
posts in the cited thread by dsjtecserv & my mentor.
He had YEARS of industrial mechanical engineering experience,
including being the chief engineer on design & construction of a
natural gas to fertilizer plant.
YMMV but has been pretty good so far :)
black iron pipe is used for gas because, when tightening a joint,
the pipes grind into one another making a tighter seal. I don't
know one way or another .... that's just what I was told. I've
heard all the other "tales". The gas (propane) in my new house is
neither. It's a corrugated flex line, covered with yellow plasticy
rubbery stuff ... looks like yellow heat shrink tubing.
What you heard was essentially correct. When you tighten a pipe fitting
with any kind of metal pipe--black iron, galvanized, brass, bronze,
etc., both threads deform--in other words, get squished--enough to
remove almost all gaps between them. That's how pipes get sealed. (What
few microscopic gaps may be left are filled by Teflon tape or pipe
Comment on quaint Usenet customs, from Usenet:
To me, the *plonk...* reminds me of the old man at the public hearing
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