Re: How does fire retardant work on fabric

JA,

As you may well know through your research already, no prduct can be made
totally fireproof, thus the term fire retardent. Fire retardent works, 
not by fireproofing anything, but by slowing the Chemical process by which 
fire builds and extends itself. In effect it does what it says in that it
RETARDS the fire. hopefully enough in order that the first arrriving fire
companies will be able to extinguish it with as little water and smoke
damage as absolutely necessary.  

Good fire retardents  contain compounds which include nitrogen,
phosphorus, chlorine, antimony, chlorine or boron. The material used is
dictated by the material being treated. The chemicals or compounds work in
differing ways: some reduce the amount of burnable fuel vapors produced by
the heated or burning substance. Others release gases which will not burn,
one being plain old water vapor, to dilute the fuel vapors. Still others
slow the rate of oxidation (fire is a chemical process involving the
rapid oxidation of a fuel being acted upon), thus reducing the rate at
which energy is released and the amount of heat generated.

The use of these retadents is a ticklish matter. If used in improper
concentrations they can result in a loss of strength or a breakdown of the
fibers over time. Some chemicals can lead to skin rashes and cannot be used
in clothing, especially infant's clothing. Some will wash out in your washer
machine. Proper fire retarding of fabrics should always be doneby a 
manufacturer rather than at home as an afterthought.

Materials which are usually considered unburnable will burn in the proper
circunstances. Aluminum will burn in a nitrogen atmosphere, magnesium will
burn in the open air. magnesium powder is very flammable, almost to the 
point of explosibility, especially if water is put upon it in inadequate
measures.  Steel in skyscrapers are compromised at fairly low temperatures
such as 600 to 800 degrees ferenheit, and so if they are part of the load
bearing structure, they are encased in concrete to insulate them.

I hope this has helped you with your project in some small way.

Thanks for thinking about us,

Donald E Duggan

(Print matter on this subject can be found in the NFPA handbook, International
Fire service Training Association's "Essentials of Firefighting" and other
publications from the IFSTA)