Perhaps the most common cause of fires in large bulk storage is self-heating leading to spontaneous ignition. Self-heating is partly due to microbial activity, chemical oxidation and physical processes and can lead to spontaneous self-ignition within a few days, but more commonly after weeks or months, depending on the circumstances.
Whether the self-heating sets off and finally causes an ignition and a fire or whether it stabilises at a temperature can be difficult to predict. The self-heating may be depending on several different reactions and physical phenomena. However, it is known that at certain conditions, depending on the material and its properties as well as the sorounding environment, a critical temperature will be reached. At the critical temperature, the heat production in the material is higher than the cooling i.e. the temperature will increase uncontrollably and the material will ignite.
RISE has studied self-heating within the work in the competence platform Fuel Storage Safety. RISE has also been part of the research program CECOST (Centre for Combustion Science and Technology) and other research projects. In the project SafePellets, RISE studied self-heating of pellets in four different scales i.e. microcalorimetry (cm3), heating basket (dm3), pilot scale tests (m3) and full scale tests in a storage silo (4000 m3).
To study a material's propensity for self-heating RISE offers traditional heating basket tests, but also tests in the microcalorimeter. Microcalorimetry enables tests at typical storage temperatures i.e. 40 °C to 70 °C.
Based on work made in our laboratory, we can offer services such as: