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Effects of Specimen Edge Conditions on Heat Release Rate.

pdf icon Effects of Specimen Edge Conditions on Heat Release Rate. (1086 K)
Babrauskas, V.; Twilley, W. H.; Parker, W. J.

Fire and Materials, Vol. 17, No. 2, 51-63, March/April 1993.


heat release rate; cone calorimeters; fire models


When bench-scale specimens are tested for heat release rate, it is generally of interest that the behavior of the specimen simulate, as much as is possible, that of a real-scale product performing in a real fire. A number of issues have been raised recently by workers trying to understand the optimal conditions of specimen preparation and mounting. In the present study a large number of materials were explored in the Cone Calorimeter to determine the effect of edge conditions and edge frames. It was found that by the use of an insulated edge frame, heat release rate values can be obtained which are slightly closer to expected true values. The testing procedure, however, is significantly more complicated. This makes the insulated edge frame useful for collecting specialized data for fire modeling, but not for conducting routine reaction-to-fire tests. For routine testing use, it is recommended: (1) that no edge frame needs to be used unless the test specimen presents special difficulties, such as due to intumescence; (2) that in those cases where the use of the steel edge frame is found necessary, the results should be reported on the basis of an effective exposure area of 0.0081 m2. When reported on such a basis, the heat release rate results do not show a systematic bias, compared to results with no edge frame.