PTFE on Gas Service Not Approved

If it has been deemed unapproved, then clearly it is not suitable according to those doing the deeming. So why the question?

Yes, they make a tape for that use, it is thicker

<...they...> Who?

Very useful. Thanks. :-)

<...read that is an unapproved sealing method...> Please advise the nature of the source document, given the content of #4 above, showing gas service, which is one of a range of <...hydrocarbon...> materials?

here

Then it would appear that the original poster is mistaken. Thanks. :-)

hydrocarbon based tape is penetrated by CH4 molecules via molecular diffusion and made more fluid and subject to gradual pressure extrusion from the joint.

Much like paint thinner on paint where methylene chloride penetrates paint films.

Thanks. Useful to know. :-)

Isn't AP#1 USUALLY wrong?

Then AP#2 shows up to say impolite things about AP#1?

HAS AP#2 shown up yet? Or are we going to have a civil conversation for once?

Note prior posts from Aurizon. In addition, Read the label!

There are tape, paste and solid (putty stick) sealant products available for pipe thread sealing. Not all contain PTFE. The label (on everything but the cheap white tape at the hardware store) should indicate, for example "UL listed for use on water, steam, natural gas and gasoline service on threaded joints up to XXXXXX...". Just asking about hydrocarbon service is not specific enough.

Don't matter. The info we are getting is that if you return a thermostat or safety valve as defective and the factory finds teflon tape in it, the warranty is voided. Not a matter of compatibility, a valve intended to control low pressure (3.5 w.c. in.) gas cannot work with pieces of tape in it. -- JHF

So they take the stand that the threads will cut tape - a more or less 2 dimensional material - into small strips and fragment that could enter the innards of the valve, which is, I agree, susceptible to obstruction and 2 to 3 inches of water pressure differential.

They should open the valve to determine the true cause, and if a tape fragment and that is cited in the warranty as cassus belli(economic - against you!!).

It has some validity as a paste will tend to cohere and harden and not make such particles, and any that occur will fall under gravity to a low point??

I was told many years ago not to use tape on instrument air lines. It could block off some of the small orifices in regulators and similar parts of the system.

A few people have also said not to use tape on any part of a compressed air system for the same reasons.

My practice is to make sure none of the tape is placed forward of the threads, over or onto the end of the pipe. If any gets cut it will not go into the pipe and will be smashed by the threads as the fitting is tightened. Otherwise I will use a Teflon paste, preferably of the better types of Teflon paste.

Good Luck, Old Salt

The question is too vague...I don't know any pro's that use tapes as sealant...but there are PTFE paste sealants for use with hydrocarbons....Teflon is more for lubrication, as in ease of tightening, than for sealing threads as in thread sealant...

http://bluebarrel.eu/shop/chemola-desco-valve-lubricants-and-sealants/tfe-104-hydrocarbon-service-contains-ptfe/

http://www.plantengineering.com/single-article/guidelines-for-choosing-a-pipe-thread-sealant/5103ee62235def2053cec5d46dd34156.html

Yeah, the stuff I use for my gas lines looks like grits (but more opaque and whiter color). It never really hardens which I guess is the point.

To wrap it up: only suitable PTFE sealant is allowed for hydrocarbon service!

Yet to discuss approved or un-approved by whom???

Approved or unapproved? either way is there a quality control audit trail to a source of authoriy? - a standard?, an insurance company?, a trade association?, a professional institute? - we do like to get our facts right!,

One thing that was not talked about was the TYPE of threads being used. If they are 'straight' threads (like on water pipes) then PTFE tame or pipe dope is needed to seal the threads, if they are 'compression' threads (male end looks like it has a cone-like tip ahead of the threads) then additional sealants are NOT required, and NOT allowed.