Evaluation of Handheld Aerosol Extinguishers with Respect to Toxicity and Corrosivity
Defense Research and Development Canada is undertaking a research project that will look for alternatives to replace their existing Halon 1301 fire suppression systems with a safer and more effective option. At the current moment, the study focuses on a relatively new and emerging alternative in fire suppression, aerosol extinguishment agents. Previous studies have been done on the effectiveness of aerosol suppression agents; however, there is very little data related to the potential impacts due to accidental exposure to the agents after discharge into a compartment without a fire, or similarly due to exposure in conjunction with fire suppression. Therefore, there is a need for more in depth experimental analysis to determine if the agents are safe enough to use for fire suppression applications where exposure of personnel, environment and equipment to the aerosols cannot be avoided. The research presented in this thesis will focus on comparison of the characteristics of two specific aerosol variants designed for use in a 20 m3 occupied space. To evaluate the potential for physiological impact, experiments were designed to assess the aerosol systems in fire scenarios similar to those that naval Rapid Response Team (RRT) would experience. Thus, the aerosols were tested in five different scenarios, including fires fuelled by diesel fuel and wood cribs, as well as under cold agent discharge situations. Temperatures in the compartment were monitored throughout each test using 80 Type K thermocouples. The compartment environment and, particularly, evidence of NO¬x, CO, HCN and NH3 production, were investigated for each situation using Novatech P-695 and Gastec STR-800 pre-calibrated tube testing systems. Finally various materials were exposed during the various test situations in order to better assess the potential for corrosion of selected materials due to agent deposition. The thesis includes a detailed description of the experimental design, measurement apparatus and techniques used in the research, as well as key results from each of the tests performed. It was found that, NOx, NH3 and CO are produced during discharge of aerosol suppression agents. In addition, there is some evidence to suggest that deposition of aerosol particulates, combined with fire residues, could contribute to degradation of surfaces when left unattended for long periods of time.