Which pipe insulation?

[womble69]

Okay, it was going to happen. Burst pipes in loft. Pipes were lagged with the usual grey 20mm wall bungee, but they froze just the same.

The pipe runs are straight, very long and go over the joists (so they don't benefit from the rest of the loft insulation. It's as if they are outside pipes. It's a very big house, with an awful lot of pipework, so it's not all kept moving either.

I would guess that the loft may have gone as low as -20C. The loft is like a deep freeze even at the best of times, so this will certainly happen again (it's now pretty clear that it came within an ace of happening last year, too).

So, what insulation to put on once the pipes are repaired? I've checked the regs for frost protection and the pipe situation is graded as 'extreme'.

Regular Climaflex may simply not be enough, even if it's physically possible to fit a greatly increased thickness (due to pipes being close together).

The loft is huge (it's like an aircraft hanger), so there's no possibility of tube heaters or anything like that, either.

Any recommendations?

 

[muggles]

You could upgrade to 25mm wall thickness, that'd give you a bit of extra protection, or you could fit trace heating which *should* prevent freezing altogether. Other than that look at Isover foil pipe insulation, which has better thermal performance than the Climaflex style insulation and is also available in larger wall thicknesses. It also looks damn sexy when installed correctly

 

[xr4x4]

what pipes are they?

 

[Nige F]

burst ones

 

[JohnD]

you might think about taking off the pipe insulation, and the loft insulation underneath them, and flopping a wide loft roll over the top. So the pipes now think they are inside the heated house.

 

[Corgigrouch]

I agree with John D... No matter how much insulation you wrap over a pipe, eventually it will freeze all the insulation will do is offset the inevitable... You need to replace the heat that is being lost, either bu replacing the water in the pipes bu running them regularly, by heating them electrically or by placing them under the insulation so that the heat rising from the rooms below is trapped under the insulation and helps the pipes stay free of ice.. Your rockwool should run over the pipes though if you turn off the heating then you are still stuffed.

 

[womble69]

what pipes are they?

Cue Monty Python.
"Ex-pipes, no longer with us ... etc".

15mm copper, cold, lagged with 10mm grey foam.
22mm copper, cold, lagged with 20mm grey foam.
22mm copper, hot, lagged with 20mm grey foam.*

*Big house, several bathrooms. This one not in use so effectively another cold water pipe.

And boy, did that 22mm go. Really spectacular 3" split, right through foam.

Pipes can't be moved though, so will have to remain outside the so-called 'insulation envelope'. So it's a question of what super-insulation to use.

 

[JohnD]

Pipes can't be moved though, so will have to remain outside the so-called 'insulation envelope'. So it's a question of what super-insulation to use.

You haven't got to move the pipe to put it inside the loft insulation. You just need to move the insulation so its over the pipes.