NFPA 257: Standard on Fire Test for Window and Glass Block Assemblies prescribes fire and hose stream test procedures that apply to fire window assemblies -- including window, glass block, and other light-transmitting assemblies -- intended for use in window openings to prevent the spread of fire through openings in fire-resistive walls. Fire barriers are only as strong as the holes poked through them. NFPA 257 establishes controls of the fire test as well as performance criteria and results for reporting procedures.
A new time-temperature curve has been added to the 2017 edition.
The new time-temperature curve was expanded from 45 minutes to 3 hours to accurately reflect the test method. In other changes, the allowed time between the test and the hose stream test has been reduced, and there's a new reference for the hose stream test procedure.
NFPA 257 is referenced by NFPA 101®: Life Safety Code® when a window opening is added to a fire rated wall, and also referenced by NFPA 80: Standard for Fire Doors and Other Opening Protectives. Essential for testing laboratories and manufacturers, the 2017 Standard edition contains updated references to ensure you're working with the latest information.