Fluorescence characteristics of common solid fuels pre- and post-pyrolysis

The study of pyrolyzing fuels is essential in both combustion and fire safety research; however there exist few reliable experimental methods by which the pyrolyzing area of a fuel surface can be identified. Quantifying the location of the pyrolysis region is critical in the study of phenomena such as flame spread over solid fuels. Identifying the pyrolysis region can be achieved through temperature measurements or through visual observations; however both of these techniques can be heavily influenced by the presence of a flame (e.g., upward flame spread). A recent study has identified that the pyrolysis region of burning polymethyl methacrylate (PMMA) can be defined using laser-induced fluorescence. This study expands on these recent findings and presents the pyrolysis fluorescence characteristics of other common solid fuels. Experiments were conducted using PMMA, high density polyethylene (PE), polyoxymethylene (POM), poly-vinyl chlorate (PVC), polycarbonate (PC), nylon (PA6), polyisocyanurate foam (PIR), phenolic foam (PF), and untreated timber (pine). Each material was first pyrolyzed in a standard Cone Calorimeter exposed to 35 kW/m2. Both pyrolyzed and virgin materials were exposed to 266 nm light from an Nd:YAG laser. The fluorescence response was recorded using a Thorlabs CCS100 spectrometer. The results presented in this work allow experimentalists to identify the material specific fluorescence signature of polymer fuels, providing an explicitly defined pyrolysis region for a wide range of fuel types.