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Window Breakage Induced by Exterior Fires.


pdf icon 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.