[Cob] Wool as insulation

[Elizabeth]

Someone asked recently about using wool as attic insulation, and suggested that unwashed greasy wool might keep off bugs.
 
This is a very bad idea.  While WASHED wool is not EASILY flammable, it will burn if it is exposed to an open flame for long enough.  It will not burn easily, and it tends to suppress the fire itself by the way it turns into ash, but it will burn.  It is rated nonflammable as a clothing item because it will not "flash", that is, it won't turn instantly into a sheet of flame if exposed for a moment or two to a match or candle flame.  
 
However, UNWASHED wool is heavily coated with lanolin, which is an oil.  It also contains a large amount of dust and dirt, and might include flammable items such as grass, hay dust, burrs, twigs, etc.  There have been cases of SPONTANEOUS COMBUSTION in unwashed wool when it is stored in large volumes in warm places.  For this reason, stuffing lots of unwashed wool into an attic is not wise.
 
In addition, once wool does catch fire, the smoke contains cyanide compounds that can cause nervous system damage--oddly, even though wool is not one of those nasty man made products, the smoke contains some of the same bad things you get if you burn, for instance, a couch with foam rubber cushions.
 
It also may contain quite a bit of manure (also flammable) or urine.  While I find the smell of sheep pleasant, in the same way that horses smell pleasant, it has a distinctive barnyard smell.  
 
Also, the best way to keep bugs out of wool is to clean it thoroughly.  I believe carpet moth larvae actually do damage the wool itself, but other bugs, such as earwigs, are attracted to to the DIRT in wool clothing and carpets (this might be true for carpet moths as well--I'm not sure.)
 
Washed wool would probably work decently as insulation, but I would still have doubts about flammability--I suspect it wouldn't be approved in a house built to code.  
 
I work with wool, both as a felter and spinner, and have read a lot on this subject.  I wish you well in your search for good insulation.  
 
Is there anything wrong, from a green perspective, with standard builders fiberglass insulation?  I would expect it to be inert and non-gassing.  Except that it is perhaps energy-intensive to make, and more expensive than something you can scrounge, and that you have to be careful not to get it on your skin when installing it, what is wrong with it for attic insulation?  
 
Elizabeth 

		
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