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Thermal Breakage of Double-Pane Glazing by Fire.

pdf icon Thermal Breakage of Double-Pane Glazing by Fire. (951 K)
Cuzzillo, B. R.; Pagni, P. J.

Journal of Fire Protection Engineering, Vol. 9, No. 1, 1-11, 1998.


National Institute of Standards and Technology, Gaithersburg, MD


glazing materials; cracking (fracturing); windows; heat transfer; equations; convective heat transfer


A model for double-pane window breakage due to heating by fire is developed that applied to both compartment fires and to urban/wildland intermix fires. This work builds on the model and computer code, BREAK1, for single-pane window breaking by fires, as described in previous publications, with additional features including the inter-pane gap heat transfer and sequential pane-breaking. A Mathcad-based computer code, McBreak, is developed that implements the double-pane model. Radiation is shown to dominate the inter-pane gap transport unless low-emissivity interior glass surfaces are used. Fires on the outdoor side of double-paned windows are included, since windows represent one of the most vulnerable features of dwellings in the urban/wildland intermix and double-paned windows help fire-harden a structure. Examples are presented for double-pane window breakage in compartment fires and wildland fires. Confirmed is the empirical observation that double-pane equipped structures might survive urban/wildland intermix fires better than their single-pane equipped neighbors.