Natural Gas Piping and Teflon tape

[MintJulep]

I'm in the process of selling my house and the buyer's inspector wrote a finding that "Gas piping has Teflon tape. Gas pipe must have the dope."

A web search reveals a lot of discussion on various home inspector and contractor foura - but no code citations.

I looked through NFPA 54 and find no clear prohibition.

Earlier versions had language to the effect of "thread sealant (pipe dope) must be resistant to the stuff in the pipe..."

I can see that potentially being mis-interpreted or mal-interpreted by home inspectors looking to give their clients more negotiating points.

The 2012 version of NFPA 54 removed the parenthetical reference to "pipe dope".

Anyone know for sure the real dope on the dope?

 

[Compositepro]

There is a yellow Teflon tape made specifically for gas piping. I think the only thing different about it is that it is thicker and denser than some of the really cheap tape. To my knowledge there is no restriction.

 

[Pud]

Not allowed here in the uk*. Too many problems historically due to small bits of it blocking appliance gas jets.

*Well, not 30 years ago when I worked in the domestic appliance industry.

H

www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.

 

[ScottyUK]

Interesting, Harry. I have some in the garage which has a British Gas approval and it seems thicker than the normal stuff. I don't do gas work, by the way, it's just a roll I've acquired at some point. I rarely use PTFE tape anywhere except radiator valve tails which have a tapered thread.

 

[Eltron]

I don't think there are any national codes against it. I know there is a mil spec for teflon tape use. Maybe it's a local building or fire code issue?

Dan

http://www.eltronresearch.com

Dan's Blog

 

[BigInch]

In the US, NFPA #8 allows gas teflon tape (double density, yellow color), or paste. Teflon tape for water (white) is not permitted to be used on fuel gas pipe. It will stop water leakage, but not always stop gas leakage. Local building codes often go along with NFPA, but some just might not. Best to check local practice with a licensed plumber.

Independent events are seldomly independent.

 

[MintJulep]

NFPA 8?

There doesn't seem to be such a thing.

http://www.nfpa.org/codes-and-standards/document-information-pages

The obvious potential typos 18. 80, 88 dont' seem relevant by title.

 

[MintJulep]

The only relevant section I see in NFPA 54 is

5.6.7.4 Thread Joint Compounds. Thread joint compounds shall be resistant to the action of LP-Gas or to any other chemical constituents of the gases to be conducted through the piping.

Earlier versions stated " Thread Joint Compounds. Thread joint compounds (pipe dope) shall be resistant..."

 

[Compositepro]

As yet I've not seen anything definitive in this thread that says any type of teflon tape is banned for gas pipes. Applying more of the single density white tape will achieve the same results as using the yellow tape, albeit with a greater likelihood of leaks due to to misapplication. Ultimately, a leak test must be conducted on all piping.

 

[TheBlacksmith]

I used some white (water) teflon on an LP gas line and it failed after a year or so. Learned about the yellow hydrocarbon resistant tape and redid the joints. When I taught boat mechanics I would not allow the use of any color teflon tape on fuel injection or lubricating oil systems due to the potential for fragments blocking an orifice.

 

[BigInch]

Teflon tape is not banned, just [highlight #3465A4]WHITE[/highlight] teflon tape.

Independent events are seldomly independent.

 

[MintJulep]

Cite a code please.

 

[BigInch]

NFPA 54

UFGS SPEC 33 11 23 UTILITIES: NATURAL GAS AND LIQUID PETROLEUM PIPING

Massachusetts Gov

http://www.mass.gov/ocabr/licensee/dpl-boards/pl/regulations/rules-and-regs/248-cmr-500.html

CA DOT

http://www.google.com/url?sa=t&rct=...urce=web&cd=213&ved=0CDIQFjACONIB&url=http://

http://www.dot.ca.gov/hq/esc/struct...sg=AFQjCNENbc094O_Dh08AF0pubba_ndSxmQ&cad=rja

Independent events are seldomly independent.

 

[MintJulep]

Thanks,

I've looked through NFPA 54, and other than the section that I quoted above I didn't find any mention of Teflon tape specifically, or thread sealing in general. Did I miss something?

Both your MA and CA citations ALLOW Teflon tape.

 

[BigInch]

Is it not in NFPA-54 section 5.6.7.4
The tape must be marked suitable for gas use, which would preclude any white, single density tape, as far as I know, even if doubled up in thickness.

Independent events are seldomly independent.

 

[stevenal]

Perhaps:

5.6.1.3 Other Materials. Material not covered by the standards
specifications listed herein shall be investigated and
tested to determine that it is safe and suitable for the proposed
service and, in addition, shall be recommended for that service
by the manufacturer and shall be acceptable to the authority
having jurisdiction.

This was pasted from an older edition, but 2012 looks similar.

 

[MintJulep]

According to DuPont there is no such thing as Teflon tape anyway.

http://www2.dupont.com/Teflon_Industrial/en_US/teflon_tape.html

 

[KENAT]

Someone ask Dave to do a find replace of Teflon with PTFE then before Dupont sues him ;-).

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[BigInch]

Rubbish! I have a carton of it sitting right next to the Scotch, Cellophane, Duck Tape and Band*Aids.

Independent events are seldomly independent.

 

[BigInch]

I've seen the 2012 edition and while not specifically allowed, it is not prohibited. That in conjunction with stevenal's quote of 5.6.1.3 would seem to allow PTFE "Teflon" (if it is marked suitable for gas).

So, best to check your local code for further restrictions.

Independent events are seldomly independent.