fire. That fire resistance gives homes built with insulating concrete forms certain
safety advantages. And those advantages give builders and buyers yet another
reason to consider using ICFs for their next project.
Unlike wood, concrete does not burn. Unlike steel, it does not soften and bend.
Concrete does not burn until it is exposed to thousands of degrees of Fahrenheit
-- far more than is present in the typical house fire.
were subjected to continuous gas flames and temperatures of up to 2000
degrees Fahrenheit for as long as four hours. None of the ICF walls ever failed
structurally. All of the ICFs tested were of the "flat" or "uninterrupted grid" type,
having no significant breaks in the concrete layer. In contrast, wood frame walls
typically collapse in an hour or less.
Concrete walls have also proven more resistant to allowing fire to pass from one
side of the wall to the other. This is especially of interest in areas with brush fires
that could spread indoors.
The fire wall test confirmed This rule for ICFs once again. Part of the test
measured how well the wall slows the passage of heat and fire from the side
with the flame to the other side. The ICF walls tested did not allow flames to
pass directly through. They also did not allow enough heat through to start a fire
on the cool side for 2-4 hours. In contrast, wood frame walls typically allow
both flame and fire starting heat through in less than an hour.
The foams in ICFs are manufactured with flame-retardant additives. These
prevent the foams from burning by themselves. If you hold a match to the
material, it will melt away.
Of course, in a house fire the foam may be subjected to constant flame from
other materials burning nearby(wooden floors, fabrics, etc.) The "Steiner Tunnel
Test" measure how much a material carries fire from an outside source. In the
test, technicians line a tunnel with the material, run a fire at one end, then
measure how far the flame spreads. The flames travel about one-fifth as far
down a tunnel lined with ICF foams as they spread down a tunnel lined with
wood.
Practically any organic material, be it wood or plastic, gives off emissions when
it is subjected to intense heat or flame. The Southwest Research Institute
reviewed the numerous existing studies of fire emissions and concluded that the
emissions from polystyrene foams are "no more toxic" than those of wood.
