Gas: sleeving pipe through wall

[Tim W]

It's hypothetical...

I was doing some water plumbing today and where I had a 15mm copper pipe going though the wall, I decided it was probably a good idea to sleeve it with a bit of plastic conduit[1] - just to stop the pipe rubbing on the brick due to expansion.

Despite pushing the sleeve almost out the other side for the duration, soldering the elbow on the pipe right up against the wall burnt the sleeve. Guess the gas flame must have licked in the hole. Oddly enough the emulsion barely discoloured and did not burn.

Not a problem this time - I can shove a new sleeve on from the other side.

But, how do gas folk avoid this problem when soldering up against a sleeved hole? We'll assume that the other end is connected to something so you can't just pull the pipe out to make the joint.

Any tricks on heat shielding could be helpful for what I'm up to.

[1] I thought about using 22mm copper as the sleeve - but then I'd have to hacksaw and de-burr it, so I tried the lazy option - and it got me thinking.

[Pete Verdon]

I don't know if it would prevent the problem entirely, but one of those glass-fibre soldering mats sounds like a good start. I use one whenever soldering near timber.

Pete

[Andrew Gabriel]

That's what I do. I plan the installation so any elbows like that are done before the pipe is fixed at the other side, but if that wasn't possible, it's easy to cut the pipe at the other side and rejoin it later.

Where you have something like a hot water pipe, which may routinely slide back and forth as the pipe expands/contracts, a plastic sleeve is probably better.

[<me9]

So what about the second joint? Unless it's compression it can't be near the wall.

[Andrew Gabriel]

Make it further away from the wall. I don't have any cases where there's an elbow against the wall on both sides of a hole.

I have one case where there's a swept bend both sides with a gas pipe. For that, I threaded the sleeve (next size up copper pipe) onto the pipe before doing the second bend. That (and some water pipes) were then threaded though the wall with a whole brick taken out, and then bricked up afterwards with each sleeve temporarily held centrally on its pipe with packing pieces in the ends whilst doing the final mortaring around them.