Dissemination monitoring by LWIR hyperspectral imaging

With the purpose of validating dispersion models, ammonia (NH3) releases were performed in September 2018 and a network consisting of NH3 detectors and temperature sensors were positioned in a grid in front of the source. In addition, the test grid was also monitored by a focal plane array imaging system based on a LWIR detector, which was positioned at a safe standoff distance of 1 km. With this setup, it was possible to monitor the release and the development of the generated cloud during the dissemination, as well as monitoring surrounding areas for risk assessment purposes during and after each challenge. As the observation was performed in near real time (approximately 0.5 Hz frame rate for the measurement, data transfer, Fourier transform and analysis), it was possible to give immediate feedback to the release team and test control personnel. Of special interest are background concentrations below the detection limit, as once these are achieved this indicates whether an area is safe and/or when additional challenges/disseminations can occur.