Cone Calorimeter – a Tool for Measuring Heat Release Rate

The cone calorimeter is considered the most significant bench scale instrument in fire testing. This apparatus has been adopted by the International Organization for Standardization (ISO 5660-1) for measuring heat release rate (HRR) of a sample. It has been shown that most fuels generate approximately 13.1 MJ of energy per kg of oxygen consumed. Therefore, HRR is based on the fact that the oxygen consumed during combustion is proportional to the heat released. This device analyses the combustion gases and measures the produced smoke from a test specimen that is being exposed to a certain heat flux. At least the oxygen concentration must be analyzed to calculate the released heat, but to improve the accuracy, carbon monoxide and carbon dioxide concentrations can also be analyzed. The data collected from this bench scale real fire test can be used for fire modelling, prediction of real scale fire behaviour, pass/fail tests etc. In this work the principle and use of this technique will be described. Since this method measures heat release rate indirectly by calculations based on oxygen consumption, the uncertainties originating from assumptions, calculations and the tested fuels will also be discussed.