NFPA 257

Abstract

Scope: <span lang="EN" xml:lang="EN">This standard prescribes standardized fire and hose stream test procedures that apply to the evaluation of fire window assemblies, including windows, glass block, and other light-transmitting assemblies intended to retard the spread of fire through openings in fire resistance&#8211;rated walls. This standard is not to be construed as determining the suitability of fire window assemblies for continued use after fire exposure. This standard provides a standardized method for comparing the performance of fire window assemblies. Purpose. This standard prescribes specific standardized fire and hose stream test procedures for determining the fire protection rating of window assemblies, glass block, and other light-transmitting assemblies used in openings in fire resistance&#8211;rated walls. This standard provides a means for evaluating the ability of a window, glass block, or other light-transmitting assemblies to remain in a wall opening during a prescribed fire test exposure, followed by the application of a hose stream. Tests made in conformity with this standard register performance and develop data that enable regulatory bodies to determine the suitability of fire window assemblies for use in wall openings where fire protection ratings are required. The tests described herein expose a specimen to a standard fire exposure that is controlled to achieve specified temperatures throughout a specified time period, which then is followed by the application of a specified standard hose stream. Variations from or changes in the construction or conditions of the window assembly as tested can affect the performance characteristics of the fire window assembly. The standard permits through-openings created by cracking, separation, or loss of glazing material, provided such openings do not exceed specified limits. This standard does not provide the following: (1) Full information regarding the performance of a specific fire window assembly where installed in walls constructed of materials other than those tested (2) Evaluation of the degree to which the fire window assembly contributes to the fire hazard by generation of heat and other products of combustion (3) Measurement of the fire window assembly\'s ability to control or limit the passage of smoke through the assembly &#160;