Previous in Forum: Sand Trap Louver   Next in Forum: Steam Table
Close
Close
Close
20 comments
Anonymous Poster #1

PTFE on Gas Service Not Approved

03/29/2016 5:56 AM

All,

Is it suitable to use PTFE sealant on hydrocarbon service. I have heard and read that is an unapproved sealing method.

Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30315
Good Answers: 817
#1

Re: PTFE on Gas Service not approved

03/29/2016 6:55 AM

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

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru
Hobbies - HAM Radio - New Member United Kingdom - Big Ben - New Member Fans of Old Computers - Altair 8800 - New Member Canada - Member - New Member

Join Date: Jun 2006
Location: Toronto
Posts: 3968
Good Answers: 119
#2

Re: PTFE on Gas Service not approved

03/29/2016 7:14 AM

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

__________________
Per Ardua Ad Astra
Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30315
Good Answers: 817
#3
In reply to #2

Re: PTFE on Gas Service not approved

03/29/2016 7:29 AM

<...they...> Who?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
2
Guru
Hobbies - HAM Radio - New Member United Kingdom - Big Ben - New Member Fans of Old Computers - Altair 8800 - New Member Canada - Member - New Member

Join Date: Jun 2006
Location: Toronto
Posts: 3968
Good Answers: 119
#4
In reply to #3

Re: PTFE on Gas Service not approved

03/29/2016 7:32 AM
TAPE COLORDESCRIPTIONEXAMPLE/TH>
Whitesingle or double density, should only be used on NPT threads up to 3/8 inch in diameter

LASCO White 1/2-Inch Double Density PTFE Thread Seal Tape

Yellowdouble density, often labeled as "gas tape"

Oatey Yellow 1/2-Inch Gas PTFE Thread Seal Tape

Pinktriple density, required on all joints 1/2″ or larger

LASCO Pink 1/2-Inch High Density PTFE Thread Seal Tape

GreenOil Free PTFE tape, required for use on all lines carrying oxygen (i.e. - medical oxygen or welding oxygen lines)

Gasoila, 1/2-Inch Green PTFE High Density Thread Tape, 3.7 mil Thick

__________________
Per Ardua Ad Astra
Reply Good Answer (Score 2)
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30315
Good Answers: 817
#5
In reply to #4

Re: PTFE on Gas Service not approved

03/29/2016 7:40 AM

Very useful. Thanks. :-)

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30315
Good Answers: 817
#6

Re: PTFE on Gas Service not approved

03/29/2016 7:49 AM

<...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?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru
Hobbies - HAM Radio - New Member United Kingdom - Big Ben - New Member Fans of Old Computers - Altair 8800 - New Member Canada - Member - New Member

Join Date: Jun 2006
Location: Toronto
Posts: 3968
Good Answers: 119
#7
In reply to #6

Re: PTFE on Gas Service not approved

03/29/2016 8:12 AM
__________________
Per Ardua Ad Astra
Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30315
Good Answers: 817
#8
In reply to #7

Re: PTFE on Gas Service not approved

03/29/2016 8:28 AM

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

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru
Hobbies - HAM Radio - New Member United Kingdom - Big Ben - New Member Fans of Old Computers - Altair 8800 - New Member Canada - Member - New Member

Join Date: Jun 2006
Location: Toronto
Posts: 3968
Good Answers: 119
#9
In reply to #8

Re: PTFE on Gas Service not approved

03/29/2016 8:38 AM

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.

__________________
Per Ardua Ad Astra
Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30315
Good Answers: 817
#11
In reply to #9

Re: PTFE on Gas Service not approved

03/29/2016 9:15 AM

Thanks. Useful to know. :-)

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru
Engineering Fields - Electrical Engineering - New Member Fans of Old Computers - Commodore 64 - New Member Popular Science - Evolution - New Member United States - Member - New Member

Join Date: Oct 2013
Location: Illinois, 7 county region (The 'blue dot' that drags the rest of the 'red state' around during presidential elections.)
Posts: 3688
Good Answers: 89
#16
In reply to #8

Re: PTFE on Gas Service not approved

03/30/2016 9:23 AM

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?

__________________
( The opinions espressed in this post may not reflect the true opinions of the poster, and may not reflect commonly accepted versions of reality. ) (If you are wondering: yes, I DO hope to live to be as old as my jokes.)
Reply
Guru

Join Date: Aug 2012
Posts: 1064
Good Answers: 92
#10

Re: PTFE on Gas Service Not Approved

03/29/2016 8:55 AM

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.

Reply
Guru

Join Date: Jul 2006
Location: CA (Central Arkansas, USA)
Posts: 597
Good Answers: 10
#17
In reply to #10

Re: PTFE on Gas Service Not Approved

03/31/2016 3:07 PM

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

__________________
If it's too good to be true, it probably isn't
Reply
Guru
Hobbies - HAM Radio - New Member United Kingdom - Big Ben - New Member Fans of Old Computers - Altair 8800 - New Member Canada - Member - New Member

Join Date: Jun 2006
Location: Toronto
Posts: 3968
Good Answers: 119
#18
In reply to #17

Re: PTFE on Gas Service Not Approved

03/31/2016 3:16 PM

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??

__________________
Per Ardua Ad Astra
Reply
Guru
Safety - Hazmat - New Member Engineering Fields - Retired Engineers / Mentors - New Member Engineering Fields - Piping Design Engineering - New Member Hobbies - DIY Welding - New Member Fans of Old Computers - PDP 11 - New Member

Join Date: Feb 2007
Location: Stronger Than The Storm
Posts: 2391
Good Answers: 202
#19
In reply to #18

Re: PTFE on Gas Service Not Approved

03/31/2016 4:06 PM

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

__________________
Any day on the green side of the grass is a GREAT DAY!, --- me +++++++++. I believe creativity is an inherent part of everyone. --- Kermit T. Frog
Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 30964
Good Answers: 1727
#12

Re: PTFE on Gas Service Not Approved

03/29/2016 12:27 PM

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

__________________
Break a sweat everyday doing something you enjoy
Reply
Guru
Hobbies - DIY Welding - Wannabeabettawelda

Join Date: May 2007
Location: Annapolis, Maryland
Posts: 7193
Good Answers: 416
#13
In reply to #12

Re: PTFE on Gas Service Not Approved

03/29/2016 6:31 PM

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.

Reply
Guru

Join Date: Mar 2012
Location: Out of your mind! Not in sight!
Posts: 4425
Good Answers: 107
#14

Re: PTFE on Gas Service Not Approved

03/29/2016 11:50 PM

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

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

__________________
Common Sense Dictates
Reply
Guru

Join Date: Jan 2006
Location: Tamworth, UK.
Posts: 1781
Good Answers: 45
#15

Re: PTFE on Gas Service Not Approved

03/30/2016 5:50 AM

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!,

__________________
When arguing, remember mud-slinging = lost ground.
Reply
Guru
Engineering Fields - Electrical Engineering - New Member Fans of Old Computers - Commodore 64 - New Member Popular Science - Evolution - New Member United States - Member - New Member

Join Date: Oct 2013
Location: Illinois, 7 county region (The 'blue dot' that drags the rest of the 'red state' around during presidential elections.)
Posts: 3688
Good Answers: 89
#20

Re: PTFE on Gas Service Not Approved

06/10/2016 2:19 PM

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.

__________________
( The opinions espressed in this post may not reflect the true opinions of the poster, and may not reflect commonly accepted versions of reality. ) (If you are wondering: yes, I DO hope to live to be as old as my jokes.)
Reply
Reply to Forum Thread 20 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Copy to Clipboard

Users who posted comments:

adreasler (2); aurizon (5); Brave Sir Robin (1); Circuit Breaker (1); horace40 (1); IdeaSmith (1); JNB (1); old salt (1); PWSlack (6); SolarEagle (1)

Previous in Forum: Sand Trap Louver   Next in Forum: Steam Table

Advertisement