Window Breakage Induced by Exterior Fires.
Window Breakage Induced by Exterior Fires.
(2954 K)
Mowrer, F. W.
NIST GCR 98-751; 46 p. June 1998.
Available from:
National Technical Information Service
Order number: PB98-148208
Keywords:
building fires; windows; ceramics; fire resistant
materials; heat flux; glazing materials; glass; large
scale fire tests; occupants
Abstract:
Exterior fires can penetrate building envelopes via a
number of pathways to become interior fires. One
pathway 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 protective
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 and a heat-resistant ceramic glass.
Potential protective treatments include insect screens,
vinyl film sun shades and aluminum foil. The
application of aluminum foil over the exterior side of a
window was found to be an effective treatment to prevent
window breadage 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. 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 expected. 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. Consequently,
vinyl-frame windows would not be suitable for use with
fire resistant glazing materials.
