There are lots of compartment test reports available. Some of the more well documented tests provide qualitative observations with a time-stamp, which can include the failure of gypsum wallboard. While I do not have specific references, I know that there are NBS/NIST test reports that provide such details.

While calcination of the gypsum wallboard is the phenomenon that produces failure, the wallboard can be breached due to full-thickness calcination, but also by local calcination at the fasteners that hold the wallboard to the ceiling. The heat conduction through the metal fasteners provides a faster rate of calcination locally than full-thickness calcination. Gravity provides the force for localized failure.

If you are looking for a means to determine the fire resistance rating of gypsum wallboard in fires through conduction heat transfer and backside temperature rise, then this test data would not be as reliable as looking at the failure of gypsum wallboard on a wall assembly. If the failure mode does not matter, then the test data for ceilings should provide what you are looking for.

Douglas J. Carpenter, MScFPE, CFEI, PE, FSFPE
Vice President & Principal Engineer
Combustion Science & Engineering, Inc.
8940 Old Annapolis Road, Suite L
Columbia, MD 21045
(410) 884-3266
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www.csefire.com