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Posted By Jim Walker
I've been asked and can't find an answer. I've Googled till my eyes ache!
Is it OK to use PTFE tape on an air line system for breathable air.
So far as I'm aware PTFE is pretty inert with regard to humans.
I can't find a MSDS but assuming there is no hazard maybe thats unsuprising.
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Posted By David Whaley
Jim,
I cannot give definitive answer but PTFE tape is used on drinking water systems, it's used in cooking pans, at one time you could even buy a PTFE spray to make you own pans non-stick. Allegedly it would not harm you. Not that I tried. But it would indicate it is fairly harmless.
David
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Posted By FJ
Whilst it maybe (and to my mind is) safe/food grade, why are you using it?- its not the sort of thing I'd naturally use in that situation- (I am not convinced of its strength to prevent a gas leak) please expand I'm intrigued....
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Posted By Garry Homer
PTFE tape and gasses. There is a special British Gas approved version that is yellow. How good it may be at higher pressures I do not know but I have seen compress air tubing with the ordinary white tape applied.
Garry
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Posted By Konstanty Budkiewicz
Our code of practice for food grade-related breathing air systems requires that PTFE tape shall not be used. This is not specifically because of the health impact, but because it may shred and partially disintegrate upon assembly and enter the air system: adversely affect the operation of filters, valves etc. Our preferred product it Locktite 577 with an activator 7471 - I also recall that the hardening time is in the order of 24 hours (look at the MSDS for current detail). A word of caution. Ensure that your staff are competent to use the products, I found an instance where we had a filter contamination because 577 was used without the hardener. At 7bar the wet solution migrated from the threads of the pipe connection and "splatted" the next down-line filter.
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Posted By Jonathan Breeze
It's not my area of expertise, but at the Merseyside Branch meeting on Tuesday, the speaker (from Gas Safe Ltd) was particularly against the use of PTFE.
His point was; "if you need it - you have a potentially explosive problem with screw thread fit!"
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Posted By Jim Walker
The system being built is quite extensive and is all welded except for one short section that might need to occasionally be removed to enable access to a service panel.
It will be breathable air only so worst case is a few filters might get blocked.
However I'll recommend the loctite route.
Thanks for advice thus far.
Anyone else want their 2ps worth?
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Posted By John J
Jim,
We have miles of mask airline pipework and don't use PTFE tape.
Tape up to the filter would probably not be a major issue. Tape after it can be (depending on mask type) be introduced into the users airways or affect operation of the mask.
I'm not sure where the comment about the explosive issue comes from?
John
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Posted By John Dempsey
Is the Loctite option good for a removable section. It probably won't be replaced very often but will need to be occasionally.
John J - what do you use for joints that have to be broken?
Cheers
John D
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Posted By Mike
I agree with most of the comments above. I have 30 years experience of both using it and avoiding its use in pipeline systems for various reasons. In our application (not food) we actually ban fitters from using loctite due to contamination problems, but particles of tape are also a problem if careless.
PTFE tape can be a fitter's crutch for sealing parallel threads (poor design).
There are two types of tape. One is pure PTFE for all applications including oxygen service. The other may have a coating on the PTFE that renders it unsuitable for oxygen service but OK for everything else.
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Posted By John J
John,
I'm reliably informed we use 'tretite'on the joints.
We wouldn't routinely split them as they are fixed and any connections/disconnections are done using quick connect fittings.
Where a joint would need disconnecting I'd suggest you make it as normal but use an approprite size 'union'. Union joints are used to help facilitate repairs, alterations and cleaning and require no sealent between the couplings.
John
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Posted By Alex Ryding PTFE Poly Tetra Fluoro Ethylene AKA Plummers Tape Fixes Everything AKA Teflon. http://www.nationwidepla...lus_Teflon_PTFE_MSDS.pdfI'd not use it in air lines due to shredding/ particulate risk. Not helpful with solutions... but helpful on your frying pan.
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Posted By CFT
Loctite 55 thread correctly fitted has been used on much of our plant, and offers us a reliable seal, our engineers use it all the time for breathable, water, etc; gas we use 'Boss gastite'.
CFT
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