Galv pipe vs balck iron/ teflon tape

Riosman · Feb 26, 2007

Two questions

1. The inspector said to never to use teflon tape on gas pipe. Use dope. He stated never to use teflon tape on pipe threads
True?

2. Gas pipe under a raised floor: Galvanzed or black iron?

Jadnashua · Feb 26, 2007

There is a teflon tape approved for gas (I think it is yellow?), but most people use pipe dope. But, you do what your local inspector wants...

Sponsor · 2022-01-29T12:20:58-0800

Leejosepho · Feb 26, 2007

Riosman said:
2. Gas pipe under a raised floor: Galvanzed or black iron?

I have heard gas should never be in galvanized because of the possibility of internal flaking that can cause havok in valves.

Kordts · Feb 26, 2007

That was back in the day, now galvanised is o.k. for gas.

hj · Feb 26, 2007

pipe

galvanized is not only proper for gas, but is required in some situations, such as exposed outdoors. The main reason for using black pipe is that it is cheaper.

Leejosepho · Feb 27, 2007

hj said:
galvanized is not only proper for gas, but is required in some situations ...

Whew, I am sure glad to hear that! In a few minutes, I am headed over to install a new blower motor in a widow's furnace, and I have been afraid to tell anyone that the last time I was there I had noticed the incoming gas line is galvanized!

Rancher · Feb 27, 2007

hj said:
The main reason for using black pipe is that it is cheaper.

And if you bury it it has to be wrapped anyway.

Rancher

Rancher · Feb 27, 2007

Riosman said:
He stated never to use teflon tape on pipe threads
True?

I'd always heard it was because a piece of the tape might break off and plug up an oriface.

Never did make sense to me.

Rancher

Leejosepho · Feb 27, 2007

Rancher said:
I'd always heard it was because a piece of the tape might break off and plug up an oriface.

Never did make sense to me.

I know of a situation where someone should have never been allowed to use pipe dope. He used so much and gooped it so heavily around the very end of the pipe that the water in the house tasted just like the stuff for several months afterward.

Coz · Feb 27, 2007

I heard what rancher heard...plugs up gas valves

hj · Feb 28, 2007

buried

You cannot legally install black pipe underground even if it is wrapped, unless it first has a factory coating applied to it.

Toolaholic · Feb 28, 2007

4 TIGHT wraps of teflon tape than pipe dope. with this you will be able to back off a fitting 90 degrees and NEVER have a leak. teflon put on LOOSLEY is what causes problems

Rancher · Feb 28, 2007

hj said:
You cannot legally install black pipe underground even if it is wrapped, unless it first has a factory coating applied to it.

Is this a new change to the code?

Rancher

Markts30 · Feb 28, 2007

Rancher said:
Is this a new change to the code?

Rancher

It is in the 1994 UPC - so I don't know if it qualifies as NEW...
sec 1211.5 and 1211.7

jfkopper · Feb 28, 2007

At least one state's plumbing code forbids the use of galvanized pipe for fuel gas plumbing. (Whether this prohibition is scientifically valid---I don't know.)

As always, best to do what the AHJ requires.

Be safe,
/kop

hj · Feb 28, 2007

rule

It has been the rule since at least 1970, and probably a long time before that.

FredC · Mar 3, 2007

Tape Vs Dope + new gas water trap questrion

I was told 2 wraps of yellow teflon + dope on balck pipe. Never heard of that before & always used Rectorseal alonefor balck pipe. Is this OK or should you stick with one vs the other?

Do you need to install 3" long drip trap at the end of a vertical line going to a cooktop for propane??????

mrclean · Mar 4, 2007

Have always been told that drip leg lengths dont really matter....more a matter of preference with the local inspectors around here. And, the only gas piping we can bury is soft copper.

Galv pipe vs balck iron/ teflon tape

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