Window Breakage Induced by Exterior Fires.
Window Breakage Induced by Exterior Fires.
(1004 K)
Mowrer, F. W.
International Conference on Fire Research and
Engineering (ICFRE2), Second (2nd). Proceedings.
National Institute of Standards and Technology (NIST)
and Society of Fire Protection Engineers (SFPE). August
3-8, 1997, Gaithersburg, MD, Society of Fire Protection
Engineers, Boston, MA, 404-415 pp, 1998.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
fire research; fire protection engineering; windows;
cracking (fracturing); failure; urban/wildland
interface; occupants
Abstract:
One pathway for exterior fires to penetrate building
envelopes is through windows and other glazed openings
that have been broken by fire-induced stresses. A
number of small- and large-scale experiments have been
conducted to evaluate the performance of various window
assemblies, glazing materials and potential treatments
under the influence of imposed radiant heat fluxes
ranging from 0.2 to 1.8 W/cm2. Window assemblies
include single- and double-pane windows with wood, vinyl
and vinyl-clad wood frames. Glazing materials include
ordinary single- and double-strength plate glass,
tempered glass, a heat-resistant ceramic glass and a
wind-resistant laminated glass. Potential protective
treatments include insect screens, vinyl film sun
shades, aluminum foil and reflective paint. the
application of aluminum foil over the exterior side of a
window was found to be an effective treatment to prevent
window breakage induced by an exterior fire. This
simple treatment could be implemented by homeowners or
other occupants of existing buildings in advance of an
approaching exterior fire. Tempered glass and
heat-resistant ceramic glass did not break under the
influence of the imposed heat fluxes; mounted in a
suitable fire resistant frame, they could be candidates
for use in new windows where exposure to an exterior
fire is anticipated. Vinyl-frame windows did not
perform well under the exposure of imposed heat fluxes.
The vinyl frames and sashes of these windows lost
strength, distorted and sagged, permitting openings to
develop even when the glazing remained intact.
Consequently, vinyl-frame windows would not be suitable
for use, even with fire resistant glazing materials.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899