Making Celotex hot?

[8aviashusband]

I've recently been close to a (contractor's) job which involved fixing Celotex sheets. A quantity of offcuts remain, and I have a possible use for some. This would involve copper pipes passing through the Celotex. The pipes carry water which may reach 100 degC.
Does anyone know how Celotex reacts to being made that hot? Does it melt?

 

[PrenticeBoyofDerry]

This product will burn if subjected to extreme heat, it will also give of toxic fumes.

 

[Deluks]

Leave an inch gap around the pipe and you shouldn't have a problem.

 

[8aviashusband]

Thanks, guys.
I'd hardly expect the stuff to burst into flames when heated to 100 degC (boiling water temperature) but I wondered if it might melt (maybe giving off nasty fumes as well).
Half the idea of using it touching the pipes was to provide insulation without creating a draught hole, so I'm not keen to leave a 1" gap!

 

[PrenticeBoyofDerry]

would you be able to fit pipe insulation around the pipes, then feed it through the celotex or is that defeating the object of using the stuff?

 

[8aviashusband]

The possible use (at the design stage only, at present) is to get the pipes from a solar panel through a (Uralite) slate roof. I had ideas of using an Alpha Slate Vent modified to take two 15mm copper tubes. This would give a neat, tidy, weatherproof entry. The tubes would need purpose made bends, and I wanted to close the gaps around them as far as possible. The maximum height available is about 50mm, so Armaflex pipe insulation (53mm dia) would occupy all the height available (and the rest). But I might have to go down that route. My thought of using a block of Celotex would enable me to tailor the insulation around the pipes, fill the remaining gap and give a firmish face to butt some kind of flashing/sealant to - all inside the vent cover.
The pipes contain a water + propylene glycol antifreeze mix, and can reach 100 degC+.

 

[PrenticeBoyofDerry]

look at this link, may have helpful info for you:
http://www.just-insulation.com/downloads.html
May have to do a bit of searching about.