Gas pipe - Solder or Braze?

[Jack26]

General question not related to any job, but,

When I worked quite a few years ago wiring Domestic CH systems for BG and others the gas pipework was installed with solder joints, some fitters using self-cleaning flux and others not. Most of the fittings used were solder ring with occasional larger jobs threaded steel pipework.

A few years later I was working in France and they have a code that all gas pipework (ours was external propane cylinders) has to be brazed. When I watched a French fitter soldering some gas pipework for us the pipes went cherry red before braze was taken. Out of interest I asked him if joint could be weakened by brazing rather than solder and he just said that the code dictated braze so that was it,

Question is then, why do we solder and not braze gas joints?

One thing I did notice was that the wall thickness of the pipe they used in France seemed a lot thicker than what we have here so possibly ok to braze without being stressed??

 

[ecowarm]

http://www.ukplumbersforums.co.uk/plumbing-forum/4045-plumbing-france-part-1-a.html

 

[mountainman]

UK solder or other acceptable method.
Not UK, whatever their preferred method might be.

I've always found brazed joints to be overkill on LP systems and a pain in the bum as the temperatures involved annealed the copper and deformed the tube.

 

[bjandthebeans]

Agreed with mountainman. Brazing is total overkill and allows heating a soft metal to an excessive temperature. Rules can be created but sometimes common sense is missing from the individual who created the rule, a Frenchman (or woman) in this case!

 

[Jack26]

http://www.ukplumbersforums.co.uk/plumbing-forum/4045-plumbing-france-part-1-a.html

Thanks for replies and my own thoughts were it might weaken the pipe. One thing I did find in a search came up with an American forum mentioning that certain gas contains an amount of sulpher which would create a problem with lead/tin solder joints hence the use of Braze.

With regard to the French plumbing link that gives a lot of detail and does describe a lot of the plumbing we had/have with formed joints. I remember in my early days one of the Ch guys was a subcontractor who had worked in the states and brought back a flaring tool to make his joints. His argument was that there was less chance of a leak because of only one joint surface. Unfortunatlythe BG inspector who used to come around towards the end of a job to sign it off was not so sure due to reduction in pipe wall when spread so the fitter used it on CH water only before eventually giving it up completly when the copper pipe being brought in became harder and split when bent. This was early 80's when we had one of our recessions and loads of copper pipe started to be imported if I remember correctly.

 

[tamz]

Different countries different rules and regs. You do what you need to do to comply with the rules in force.

 

[markfxy]

They seem to braze everything, hot & cold and heating pipework the French copper tube is 1mm wall thickness so even though its annealed it still retains some strength unlike British copper which is comparable to bacofoil and distorts just by gripping it too hard.

 

[mountainman]

Doesn't make it better though and makes it virtually impossible to dismantle an existing fitting.
I've dealt with both and I know which I prefer.

 

[markfxy]

Didn't say it was any better but its as easy to heat up a brazed fitting and pull it off as it is a soldered fitting

 

[bjandthebeans]

No surprise to me that the French pipe has a thicker wall and backs up the brazing practise but IMO the standard is still over specified. I've randomly brazed and welded different metal types for long enough (decades!) but soldering copper or alloy pipework really is straightforward to apply with the proper techniques and fittings but as the old saying goes - 'Everyone to their own!' :smiley2:

 

[Bernie2]

Be interesting to watch them repair a gas pipe in an old under floorboards space. The heat from brazing would probably set the place on fire.

 

[sheff paul]

Be interesting to watch them repair a gas pipe in an old under floorboards space. The heat from brazing would probably set the place on fire.

Brazed everything in Aus, a right pain under hobs and sinks trying not to torch everything A flaring tool is used instead of compression fittings ,expanders are used instead of Y1's for straight connection.Far better and easier plumbing systems in UK.Most of Europe brazes copper and look how rubbish their work is.

 

[Dannypipe]

What flux do you use for brazing?

I hardly do any brazing, though I do have a few rods on board incase I have too.

Last time I just used ever flux, and it did work, but I'm sure there must be proper brazing flux available?

 

[Mike Jackson]

The rods I use are fluxed.


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[Dannypipe]

The rods I bought might be too. I guess it will say on the packet.

As said I don't braze very often.

I heard a brazed joint can actually have a lower pressure rating than a soldered one, due to the annealing of the copper tube.

I've done it to repair a brazed joint on a thermal store. Not bread and butter work though.

 

[Mike Jackson]

I braze the odd joint when I'm working on caravans if there's not room to get a compression fitting in. Out of situ though.


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[stevetheplumber]

i braze the odd joint when i'm working on caravans if there's not room to get a compression fitting in. Out of situ though.


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i brazed the fittings on my motor home solder can fracture with the movement of the van

 

[SimonJohns]

i brazed the fittings on my motor home solder can fracture with the movement of the van

I thought motor homes had to use a manifold system with compression fittings?

 

[Mike Jackson]

Caravans and motor homes can be compression or brazed for the gas.

 

[quality]

I do a fair bit of brazing on pipework that works at 25 bar with no problems (on refrigeration systems). I use a phosphorus brazing a rod with no flux. But its to much effort, not nessesary and far easier to solder fittings on LP systems as previousley mentioned

 

[Bernie2]

I agree no need to braze on low pressure systems its overkill and possibly weakens annealed pipe. Certainly an expanded joint or drifted is weaker than a coupler.