Use of compression fittings for gas?

[Shadow Catcher]

I decided to run this as a separate question. The Bulfinch gas point that I imported from the UK which is now installed in the side of Compass Rose uses a compression gas line. There is no chance of being able to replace it with anything else due to the construction. I realize that in the US compression fittings are generally not accepted for flammable gases. Does anyone have any insight as to why this might be if the fitting is properly pressure/leak tested?

[Dale M.]

I 'm not sure whats proper, but personally I have had a lot better success with flared fittings and very little success with compression.... Compression always seem to leak for me and even tightening them continually they always leak, at some point the integrity of the compression fitting is compromised and probably cause them to leak MORE....

Dale

[Martiangod]

It is because a compresion ring can slip and they have a bad habit of starting to leak ...... Later.
The only compression allowed in North America, as far as I know, are on the pilot side of the gas control, but then it is aluminum tubing at that point, much softer then the copper compression ring, therefore the chance of successful compression is high, plus its at very low preasure at that point, and never static, because the pilot line is always open, so no preasure
They are allowed in England, but so is soldering gas lines allowed there also.
As for compression, if it is not in a fully accessable location, the system will be ordered disonection untill rectified, so eben they know there is a problem with compression fittings

[angib]

Compression fittings on domestic gas pipe has recently become bad practice (not, I think, illegal) in Britain - though I have 50-year-old compression fittings in my gas pipes under the floor. I'm not sure of what is good gas practice for trailers/RVs.

[mikeschn]

It appears the compression fitting is on the inside...



So if it leaks it'll leak into your living quarters.

Can you isolate that area so that in case it leaks it leaks to the outside?

Mike...

[Martiangod]

And if there is a fire or worse, and the appliance, fittings are not UL listed, CSA, CSA International, ASTM, Warnock Hersey certified for propane use, then the liability is placed on you, the owner for using unregistered appliance.
Now that doesn't only apply to the pipeing and connection behind the wall, but also to the QC fitting or attached hose, that is very likely not registered in North America.

[Shadow Catcher]

The fitting is right next to the gas water heater and right above it is a gas detector and above that is the cook top. I found that I have a flaring tool so I will be flaring the gas line Y and will periodically leak test the Bullfinch. Interestingly one recommendation is to use teflon tape on the thread of the compression fitting.

[Dale M.]

The fitting is right next to the gas water heater and right above it is a gas detector and above that is the cook top. I found that I have a flaring tool so I will be flaring the gas line Y and will periodically leak test the Bullfinch. Interestingly one recommendation is to use teflon tape on the thread of the compression fitting.

The only application where Teflon tape functions effectively is "tapered" (NPT) pipe thread fittings.... Teflon tape by definition is not a sealant but a lubricant allowing the tighter fitting of tapered threads to create a better "seal"... On anything other than tapered thread is probably pretty much useless and problem than more of a solution... I being old and grumpy and always seem to have trouble getting tape to stay on threads effectively and in a timely manner still rely quite a bit on the old stand by that never fails ..."Pipe Joint Compound" also referred to as "pipe dope"...



Or maybe ...



Dale

[Martiangod]

Gas detector should be at floor level, propane is heavier than air

[ibbuckshot]

I was advised by a propane gas dealer / owner NEVER to use compression fittings on any gas lines and fittings ! ! ! Just a word to the wise......
Have fun
buckshot

[bobhenry]

Flammable Gas



In section 1910.110(b)(8)(iv) of “Storage and Handling of Liquefied Petroleum Gases,” OSHA requires that “pipe joints may be screwed, flanged, welded, soldered, or brazed with a material having a melting point exceeding 1,000 deg. F. Joints on seamless copper, brass, steel, or aluminum alloy gas tubing shall be made by means of approved gas tubing fittings, or soldered or brazed with a material having a melting point exceeding 1,000 deg. F.” Since OSHA only includes “screwed” and “flanged” and not compression fittings in this requirement, you cannot use them with copper tubing or with PVC for LP gas

[Coop505]

I would also like to point out that a joint of any kind should never be enclosed in a wall or any place inaccessible.....Use a continuous run of tubing or black pipe....Always use flare fittings only....

[Shadow Catcher]

The gas point has been in since I started this thread, I check it and all of the other joints (flare) for leaks each spring. I understand US standards but the gas point meets UK and presumably EU standards.

[Coop505]

The gas point has been in since I started this thread, I check it and all of the other joints (flare) for leaks each spring. I understand US standards but the gas point meets UK and presumably EU standards.

Not sure why they don't allow compression but I was a plumber for over 20 years and we always used flared fittings as required by code. Most plumbing codes have a specific reason for being used so my guess is that they tested and rejected the use of compression fittings for a good reason, probably leaks or the potential for leaks. Sounds like yours is holding up though.

[MtnDon]

Way back before I knew any better I changed a connection on our old Class C. I used a compression fitting. No matter how I tightened it there was an almost imperceptible leak. After I redid it using a flared fitting it was leakproof. Your experience may differ.