Class A Foam Water Sprinkler Systems
Class A foam is often used in the suppression of wildland and structural fires, with manual application methods. This report examines the feasibility of utilising class A foam extinguishing medium in automatic wet pipe sprinkler systems. Previous researchers report that for certain applications the addition of class A foam solution to a sprinkler system increases suppression effectiveness. Researchers investigating applications with manual fire fighting techniques, using this extinguishing medium, report mixed conclusions. The integration of class A foam hardware with standard wet pipe sprinkler technology is discussed. Consideration is given to potential corrosion effects and compatibility with sprinkler hardware items. A review of environmental issues revealed that some products are readily biodegradable, while others are not, and that results vary with the test method used. Tests undertaken to investigate the relationship between the applied sprinkler head pressure and the foam expansion ratio, revealed that only a slight increase in the expansion ratio occurred when the pressure was increased from 50 kPa to 85 kPa. Expansion ratios obtained were similar to those obtained by other researchers using AFFF type foam solution. Foam-water distribution tests indicated that the distribution densities obtained with class A foam sprinkler arrays are within close proximity to the densities obtained using pure water. It is suggested that future work in this area should be based around the protection of extreme class A hazard type fires.