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Analysis of Inter-laboratory Testing of Non-loadbearing Gypsum/Steel-Stud Wall Assemblies



William L. Grosshandler, Samuel L. Manzello, Alexander Maranghides, T Mizukami


This report summarizes the results of a test program conducted in 2006 and 2007 by the North American Fire Testing Laboratories (NAFTL) consortium. Gypsum/steel-stud wall assemblies, nominally rated at 1-h, were tested by six different organizations in North America employing ten different furnace facilities following the guidance provided in ASTM E 119-00. The participating NAFTL laboratories arrived at an identical 1-h rating for the gypsum wall specimen tested according to their respective standard operating protocols. The average time to failure (defined by the temperatures reached on the unexposed side of the specimen) was 65 - 2.8 minutes. The variability in individual peak thermocouple temperatures measured at similar locations on the different wall assemblies exceeded - 50DGF around one hour into the test, and reached a maximum of close to - 150DGF at the average time of failure. Differences in the time to failure for the ten close-to-identical wall assembly tests did not correlate at a statistically significant level with differences in average furnace temperature, the temperature-time integral, changes in ambient temperatures, or standard deviation among the furnace control thermocouple temperatures. Six inter-laboratory tests were also conducted by several Japanese organizations, yielding an average time to failure of 67.1 - 1.1 minutes. The inter-laboratory program described in this report is the largest ever conducted for fire resistance testing and forms the basis for future programs aimed at testing addential structural materials, elements and systems subjected to fire test standards referenced in building codes.
NIST Interagency/Internal Report (NISTIR) - 7471
Report Number


gypsum, walls, wall assemblies, fire tests, steels, furnaces, ASTM E 119, standards, failure, thermocouples, gypsum board, specific heat, temperature, fire resistance rating


Grosshandler, W. , Manzello, S. , Maranghides, A. and Mizukami, T. (2007), Analysis of Inter-laboratory Testing of Non-loadbearing Gypsum/Steel-Stud Wall Assemblies, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 19, 2024)
Created December 1, 2007, Updated November 10, 2018