Design fires with mixed-material burning cribs to determine the extinguishing effects of compressed air foams

Abstract This study evaluates the efficacy of compressed air foam (CAF) in comparison to common fire extinguishing media. Newly developed mixed-material burning cribs were used as a normative fire load for extinguishing tests to accurately represent the significantly elevated utilization of synthetic materials in everyday life. A series of outdoor experiments was carried out to analyze the effectiveness of the fire extinguishing medium CAF using synthetical class-A foaming agents from two different manufacturers, and compared them to water and water-foam solution as a function of the extinguishing distance. In a second series, performed inside a fire room, the efficiency of CAF-usage in indoor fires was evaluated. Moreover, the results of the indoor test series provided information about the composition of smoke gases based on the kind of extinguishing tactic used to suppress the fire. The results showed that under the tested conditions CAF suppressed fire more effectively than both water and water with foaming agents. CAF was able to wet areas hardly accessible to other extinguishing media, and due to its various simultaneously occurring effects and its compact jet with high kinetic energy, it cooled down temperatures more efficiently than water or water-foam solution.