Fire Safety Science Digital Archive

The cone calorimeter (ASTM E1354lISO 5660) has been suggested as a replacement or alternate for ASTM/E136/ISO 1182 in classifying the combustibility of materials. While the cone offers several advantages over the existing test, this paper identifies two potentially serious shortcoming as well: (1)the sensitivity of measured values to sample thickness and orientation, and (2) poor reproducibility at low levels of heat release which characterize noncombustibility. The first of these difficulties makes the results dependent on the scenario in which the material is to be employed; the second issue makes it difficult to obtain reliable measurements for combustibility classification. It is proposed instead that combustibility be classified on the basis of bomb calorimetry, ASTMD2015/ISO 1716. Like the cone, bomb calorimetry provides a continuous scale of combustibility, but it is also scenario-independent, more reproducible and gives rise to combustibility classifications which are directly relatable to those in current use.