Results of the R-20F Method for Measuring the Water Equivalence of the Isolation Effect of Foams Used in Fighting Forest Fires

Abstract

Introduction: Aerial firefighting is a very expensive solution; however bombing just pure water is not always enough to suppress the fires. In many cases retardants or special agents are added to water to increase efficiency, wetting it or creating foam. Methods: This research used dried pine wood pieces as samples. Samples were divided into different groups: not treated samples for giving the reference data or treated samples to ensure data for calculating the isolation effect of foam. During the experiment with a randomly chosen foam agent product a 3% foam solution was mixed. From this solution 6 – 9 – 12 expansion rate foams were generated. Samples were also provided with a metal ring to ensure the exact depth of water or foam blanket. Each sample was put in a special heat oven which ensured the permanent 35 kWm-2 heat fluxes and measured the different ignition time. Results and discussion: Experiment demonstrated that the ignition times in case of foams are longer than in case of same equivalent pure water. The longer ignition time of foams can be expressed by the pure water amount. Results say that the maximum rate of isolation effect in value of water equivalent is more than 2.3 but always significantly more than just pure water.