(81al) Experimental Study of Ignition Bulk Storage by Hot Points

Fire and explosion risk is generated by chemical or biological oxidation of combustible materials. An experimental study of ignition risk due to hot points in the storage of bulk materials is required to ensure fire safety. Many parameters are involved in this phenomenon: the nature of the material, storage volume and temperature, type and size of hot point, etc. The aim of this study is to describe an adapted experimental protocol to determine critical ignition temperatures of powders under different conditions and with several types of hot points. Material selected for this study is a powder of « Lucy coal ». Ignition was carried out in 1000 and 2700 cm3 cubic baskets by two sizes of inert cylinders at a given temperature and by an inert sphere at a given initial temperature. The critical ignition temperature is defined as the hot point temperature in the centre of a 5°C interval of the 2 temperatures: 1) ignition and 2) no ignition. First results demonstrate that the set-up protocol is operational. Critical temperatures measured for the two cylinders and for the sphere are in the same range. Discrepancies between the results obtain under these three test conditions have been explained considering basket sizes and hot points geometry. Data obtained need now a comparison to available theoretical modeling. These results will then allow predicting material behavior under other storage conditions.