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Insulate or trace heat?


Oz07

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Got to pull a hot and cold down from a first floor ensuite, above an entry, down thru the entry back into wall at ground level. Has to go outside into entry for various reasons.

 

I had assumed pipes could just be insulated as in foam lagging as thats what you see in outhouses. My plumber (although not having seen the job thinks it may freeze). Were in the midlands and the entry is closed of at one end (so no breeze thru), the pipe drops will be halfway down entry. I cannot imagine the water freezing in there if lagged but perhaps am being naive. We are in the midlands.

 

What do you lot think?

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I thought insulation would be plenty as have done this with standpipe before. However have known pipes to freeze in houses but suppose they are unprotected. 

 

Any reason rodents would go for the insulation?

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I put some of that yellow, foam, scaffolding protection (like pipe insulation) on a couple of poles in the garden (kid's treehouse) and the birds had a right old go at it BUT only on the horizontal sections where I guess they can perch. Most external pipe lagging I see on commercial roofs has like a "zinc" shell over it. You could roll some gauze like I just did for where my 63mm duct comes up through the suspended floor with the mains water  pipe in:

 

20161001_170150

 

I was told recently of an EPDM roof job on a school where birds had destroyed it. Seems that they drink from any pooled water and eventually damage the roof. They then go mad for the PIR insulation. Something I think to do with it aiding their digestion like grit does naturally. Or maybe it's like humans with bubblewrap!

 

(I considered running trace heating up the drive set at the same width as the car wheels.....:ph34r:)

Edited by Onoff
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Is this to run a hot and cold supply through an un-heated space rather than on an outside wall ..??

 

How often will the pipes be used ..?? In most instances you are better increasing the pipe size to 22mm as it has a higher volume of water and therefore freezes more slowly. I can run the numbers through CIT but from memory you will need 22/28 in PE Foam or 22/25 in nitrile rubber to give you 8 hours or so frost protection at -5c

 

For protection can you box the pipes in too ...?? Neither of those insulation products are fully UV stable and will degrade over time so really need some sort of enclosure 

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57 minutes ago, Nickfromwales said:

Can they be chased into the wall and fully cemented in? A 9mm wall Armorflex will suffice then. 

What are the new pipes feeding? Can they be reduced to 10mm?

 

@Nickfromwales I slightly disagree with you on that one ..!! Whilst 10mm could be chased into a wall, there is significantly less water in the pipe and therefore the time to freeze becomes dramatically shorter - at -10c, a 22mm pipe with 45c water in it and 10mm insulation will freeze in 14 hours. The same spec but a 10mm pipe will freeze in less than 6 hours. 

 

The problem becomes pipe size and insulation as 22/25 is 72mm deep ..!

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These pipes come thru ceiling of an entry, down an external wall, and back into the house at close to ground level. Yes hot and cold to downstairs wc 

 

This pipe work will be external and down an external wall but in a entry between 2 properties. No other route for various reasons. 

 

Intetesting comment re 22mm pipe. I'm thinking belt n braces for the small cost of 6m of trace kit as electrician has work to do anyway may be just better off using this. No problems re clipping pipe then

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