Which pipe insulation for outdoors?

[henry1]

Can you recommend any pipe insulation which is waterproof (& UV resistant?) and suitable for outdoors?
I can't find any which says so in their specs.

 

[ajstoneservices]

Armaflex HT

 

[henry1]

That's what I was looking at but this description didn't say anything.
The project is to extend a central heating system into an external room very close. I plan to drop the pipe just below ground and insulate. Is there anything else I need to be aware of?

 

[ajstoneservices]

I would put the insulated pipework into a length of drainpipe too.

edit: it has to be ht armaflex not class o see here

 

[henry1]

For protection against mechanical damage?

 

[ajstoneservices]

Yes, And you dont want that insulated pipe sat in wet ground. see my edit above

 

[henry1]

Difficult to stop it being in wet ground if I plan to bury it. Even in a drainpipe, water can still get to it...
What's the insulation used to protect condensate pipes?

 

[ajstoneservices]

Get yourself some spray foam to inject at both end. If you put the insulated pipe into ground without the pipe the heatloss will be huge when the ground is wet.

 

[henry1]

Good idea. Isn't that spray foam good enough to replace the other pipe insulation?

 

[dilalio]

Good idea. Isn't that spray foam good enough to replace the other pipe insulation?

Do you mean use the spray foam all the way down the drain pipe to surround the heating pipe, instead of the armaflex?

If you do, then NO! You'll not know if it's gone all the way, AND... It won't centre the pipe within it.

Just do as @ajstoneservices has advised, why would you want to muddy the waters?

 

[henry1]

Why is it so bad to use the spray foam as insulation?
I'm happy to use the other one but just wondering. the more insulation the better if I get to fill the drain pipe with the foam.

 

[dilalio]

As I said... You won't be able to guarantee that the foam will fully encompass the heating pipe... It could end up pinned against the outer drain pipe and thus not fully insulated!

 

[bernardgreen]

Ready made twin pipe insulated underground ducting is available

http://www.buffertanks.co.uk/shop/microflex-pre-insulated-underground-heating-pex-pipe-32mm-duo

The important bit is to ensure water cannot get into the duct. Hence the duct is best when it is one continous length. If joints are necessary then they should be solvent welded to ensure no leakage into the duct

 

[dilalio]

https://groundbreaker.co.uk/products/shalloduct/

 

[muggles]

That's what I was looking at but this description didn't say anything.
The project is to extend a central heating system into an external room very close. I plan to drop the pipe just below ground and insulate. Is there anything else I need to be aware of?

Pre-insulated pipe is the correct stuff to use for this application

http://www.buffertanks.co.uk/shop/m...derground-heating-pex-pipe-25mm-duo-per-metre