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On the Significance of Transient Heat Release Rate Excursions Above a Set Limit



Thomas J. Ohlemiller, Richard D. Peacock


When a heat release rate limit for a consumer product is set by a regulatory agency, it is of interest to know whether small excursions above that limit, such as may occur due to production line variability, represent a disproportionate increase in fire hazard. This paper examines this issue. The heat release rate curve of the object is described by a Gaussian time variation; a perturbation peak, also Gaussian, is added to this main peak. The consequences for the build up of hazardous conditions in a room fire (where the object is the only item burning) and for the threat of ignition of secondary items are examined. For the peak heat release rate domain studied here, only the ignition threat is significantly affected by the perturbation peak. The results show the trade-off between the height of the perturbation peak and its duration for a fixed percentage of increase in the room area threatened by secondary object ignition.
Fire Safety Journal


flammability, heat release rate, ignitability, room fires


Ohlemiller, T. and Peacock, R. (2008), On the Significance of Transient Heat Release Rate Excursions Above a Set Limit, Fire Safety Journal, [online], (Accessed May 22, 2024)


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Created November 1, 2008, Updated February 17, 2017