Measurement of infrared radiation emitted by the flame of a vegetation fire

An experimental study has been carried out on the radiation emitted in the infrared by a flame produced by the combustion of vegetation (vine branches) in a square tray of size 50 × 50 cm. Measurements have been performed with an FTIR spectrometer and an IR camera on the corresponding flame with characteristic height between 50 cm and 1 m. A specific device has been built in order to allow the simultaneous acquisition of spectra in the range between [1000–6000 cm−1] and pictures in selected bands of the infrared. Pictures with a camera in the visible range have been taken at the same time. A preliminary calibration using a reference emitter has been done in order to evaluate the emitted radiation quantitatively. By comparing the emission by flames with the one of this reference surface, the radiation emitted by a vegetation flame has been observed and analysed as a function of the wavenumber. The emission is observed to be predominant in a range around 2300 cm−1, due to CO2 production, and strong emission bands related to H2O are also observed. The experimental tools, FTIR spectrometer and IR camera, both in good agreement, show a weak emission due to soots, at least at this scale of relatively small flames.