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Gypsum Stairwell Enclosure Wall System Tests under Uniform Static Pressure



Hai S. Lew


The importance of the structural integrity of the exit stairway enclosures was clearly shown by the collapse of the World Trade Center Towers. The investigation report of the National Institute of Standards and Technology recommended that the design, functional integrity, and survivability of the egress and other life safety systems should be enhanced by considering accidental structural loads. Following this recommendation, the Ad Hoc Committee on Terrorism Resistant Buildings (TRB) of the International Code Council (ICC) advocated a code change proposal on the structural integrity of exit stairway enclosures during the 2007-2008 code development cycle of the International Building Code (IBC). The proposal required that for all buildings more than 420 ft in height, the exit stairway enclosure wall surface should be capable of resisting a uniform static pressure of not less than 2 psi applied perpendicular to the exterior of the enclosure. This report presents results of three two-hour fire rated gypsum stairway enclosure assemblies, which are commonly used in high-rise construction, subjected to a uniform static pressure applied to the surface.
NIST Interagency/Internal Report (NISTIR) - 7615
Report Number


Enclosure, gypsum, stairwell, tests, walls.


Lew, H. (2009), Gypsum Stairwell Enclosure Wall System Tests under Uniform Static Pressure, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 13, 2024)


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Created July 22, 2009, Updated February 19, 2017