Penetrations through frost heave insulation

[Liam Nesson]

Hi All,

I have a number of sites that have a small generator (with day tank) and a small modular non-heated building(4mx4mx4m) both have their own concrete foundation that sits on frost heave insulation. My contractor wants to run a number of 100 diameter electrical conduits through the insulation. Most literature I have read says to prevent cold bridge in frost heave insulation:

1. Has anybody dealt with this in the past? What rational did you use?
2. How many penetrations is too many?

Thanks

 

[dik]

Often... I't nice to see the insulation carry up the face of the concrete to the wall with the wall insulation extended out. The more penetrations, the more the heat loss. Other than that, the concern is condensation. In some environments, frost penetration can be in excess of 6'.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Craig_H]

4" conduit will be a pretty substantial hole, and I would be somewhat concerned about getting some sort of convection going inside the conduit (moving air from inside to out or vice versa). That could result in substantial heat loss and potential condensation.

Not sure of electrical code implications, but could the conduit potentially be packed with mineral wool insulation or something similar at the building boundary to provide insulation continuity?

 

[dik]

I received an eMail from the MCAA this morning about a product. I'd sent them information about a webinar on the product about two weeks ago, because it appears to be an excellent product and one that is timely. FOAMGLAS perinsul SIB. I'm not a spammer.

https://www.foamglas.com/en

New thermal bridging solution for exterior masonry veneer walls reduces heat loss, improving energy efficiency.

Features*

High compressive strength
Long-term thermal performance
Dimensionally stable
Moisture impermeable and non-absorbent
Lightweight and easy to install
Available in (3) sizes that match standard masonry bricks




-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Liam Nesson]

Thanks for the responses

I will see if they can seal the end of conduit after the cable is pulled through. I will ask my electrical friends about insulation in the conduit.

Frost heave is my main concern as this is a raft foundation with the building raise up on pedestals. Some sites have frost penetration as much as 3m.

I also reached out to an insulation manufacturer to see if they had any details (I cannot be the first person to do this), below is the response:

If the insulation is sealed to the pipe on the exterior side, there will be minimal opportunity for the cold to follow the pipe through the insulation into the ground below. The insulation will keep the ground temperature fairly even below the slab even with the penetration. What is important is to properly seal the penetration around the foam with an insulating and air sealing material. The conductivity of the pipe material may drive some heat loss but we do not see it being significant to cause issues.

Thanks Dik

It is too late for me to spec a new material, insulation is in the ground for one site anyhow. I will have a better look later.

Thanks,

 

[Craig_H]

Good to hear you got it sorted out.
Dik, that insulation is a neat product. Interesting that it's been around so long and yet I've not run across it yet. Are there vendors/distributors in Western Canada? The literature mostly focuses on Europe.

 

[dik]

I'd only used it once about a decade or so back, and forgot all about it. There was a webinar about a month ago where it was used, and with current climate issues and insulation and building envelope requirements. I thought the product had merit and sent a link to the MCAA to let them know (I'm on their mailing list).

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[TLHS]

Craig, Foamglas / cellular glass insulation is used pretty regularly for piping, and I know it's around in Western Canada in at least that capacity.