Aerogel-Infused Coating for Thermal Break
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| Posted in Green Products and Materials on
During a project review with our architect (has his CPHT/CPHD) he mentioned the possibility of using an aerogel infused spray on coating called “Aerolon” from a firm named Tnemec (www.tnemec.com) as a possible solution to mitigate any potential thermal bridging in our project not easily solvable by more traditional methods. I’ve been a big fan of Aerogel in its various forms for many years but was not aware it was now available in a spray on coating. Checking with the GBA community on anyone’s experience or background with this or similar type coatings.
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"Insulating paint" sent my eyebrows to the sky, because there have been some very scammy products marketed as insulating paint, claiming absurd R-values (there are some articles calling them out on this site). However, I looked this stuff up and I don't think it's a scam -- but construction is not really a good application for it either. The spec sheet is here: https://tnemec.com/products/series-971-aerolon-acrylic/ -- note that the thermal resistance is quoted at R-4.1 at one inch, which is a physically reasonable number comparable with things like EPS foam -- but as a "spray-applied coating" they're recommending application at a rate of 50 mils (0.05") thickness per coat, so it'd take a while to get any significant R-value built up!
The intended application for this stuff is coating metal pieces in industrial / building plant applications -- think big pipes carrying chilled or hot process fluids. In that application, the comparison is between steel, with a thermal conductivity of 45W/m*K and this stuff, with a thermal conductivity of 0.0356W/m*K -- the claim is that even a thin coating reduces the thermal conductivity enough to improve safety (ie the time it takes to burn someone when accidentally touching a hot pipe) and reduce condensation on cold pipes, while also protecting pipes from corrosion.
I'm not in a position to evaluate whether these claims are valid or not, but they're at least physically believable -- but the fact remains that to get any substantial R-value out of this coating, you'd need to build it up to a thickness comparable to standard insulation materials -- and it'd definitely be easier to use something else in standard construction, unless you have a bunch of 12" chilled water lines running through your house. I'm betting your architect saw this specified on a commercial project, or perhaps saw a seminar on it as part of continuing education, and thought it sounded cool -- but I can't see any application for it in residential construction that couldn't be better solved with another material.
Those numbers would give them a very tiny by over R 0.2 in that 0.05" thick coating. Not nothing, but not enough to really do anything in terms of reducing thermal bridging, either. A layer of 1/2" polyiso would be R3, fifeteen times better.
I can understand their interest in safety in industrial settings. The usual things I work with are chilled water lines, running around 40-45F or so, and those don't have much trouble with condensation. The hangers only contact the pipe through a relatively small contact area in the "saddles", and the rest of the line has a rigid fiberglass insulating wrap. It might be different with high pressure steam lines though, which can be up to 1,000F or more, a little extra protection might be really helpful.
Bill
I agree with Jonny. Tnemic is a legitimate company; they've been making high-quality metal coatings forever, but I don't see where this product would make sense on a construction site.
What's the detail that specifically wants a thermal break coating? I'm having a little trouble imagining a situation where a thermal break coating is the only solution.
Is it something where a structural thermal break product could be used? For example, rather than coating a metal structural element that passes through the envelope, perhaps a structural thermal break could be used to separate the interior and exterior portions. Here is an example of a structural thermal break product: https://www.armatherm.com/thermal-break-materials/armatherm-frr/