Submitted by DonHester on Thu, 06/21/2012 - 13:49.
Fiberglass Insulation should we scratch the stuff?-Leavenworth and Wenatchee Home Inspection service.
We all know how we feel when it gets on us, or better yet in us. So what is it doing to our lungs if we breathe it? I know after I perform my home inspection and I had to traverse areas with fiberglass I feel it.
Here is a link to a blog I wrote concerning fiberglass, more specifically glass wool fibers that are inhalable which includes fiberglass. (Link) This blog has a link to the reference documents.
An article excerpt from the referenced literature- “Certain glass wool fibers (inhalable) are reasonably anticipated to be human carcinogens based on (1) sufficient evidence of carcinogenicity from studies in experimental animals of inhalable glass wool fibers as a class and (2) evidence from studies of fiber properties which indicates that only certain fibers within this class - specifically, fibers that are biopersistent in the lung or tracheobronchial region - are reasonably anticipated to be human carcinogens.”
So now that we have some reasonable risk associated with it let next think about how it performs as an insulator.
The basic principle of any insulation material is to limit the ability of heat to transfer its energy. (Here is a link on insulation principles (link))
With fiberglass insulation we have two principles at work, one- glass which it is not a great conductive insulator and two- we are trying to trap air to create convection loops to limit the heat transfer through convective heat transfer.
But there is a hidden issue with fiberglass. It may not be trapping the air as we hope. Because of air circulation and natural convection, the R-value of blown-in fiberglass insulation actually decreases as the temperature drops. We seem to get much more air bypass with fiberglass than other forms of insulation also.
The other inexpensive alternative to fiberglass is cellulose. Cellulose has much better resistance to air flow and convection. Because of this it prevents the upward movement of air caused by temperature differences so the actual R-value of cellulose will improve as the weather gets colder.
So this brings to the main question, if fiberglass may be a carcinogen and it may the poorer choice as an insulator why is it so prevalent?
So what are your thoughts?
Maybe as home inspectors and contractors we should start an open discussion on this and move to better alternatives.
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