2020 Volume 70 Issue 3 Pages 75-82
Since motor gasoline is a highly volatile liquid fuel, the gasoline vapor generated from the liquid surface mixes with air to form a flammable air-fuel mixture in the surroundings. For this reason, when gasoline is spilled on a floor for the purpose of arson, attention must be paid not only to the fire hazard of the gasoline spill on the floor, but also the fire hazard of gasoline vapor that has already evaporated and diffused. The foam extinguishing agent products prevent the evaporation of gasoline and ignition of gasoline by covering the liquid surface of the gasoline with foam, but are not effective for gasoline vapor in the gas phase. In this study, we proposed a method for spraying aqueous film forming foam extinguishing agent containing low-volatile oil (hybrid combustion inhibitor) to gasoline spill in order to remove gasoline vapor and make the flammable gas incombustible. First, the vapor pressure change was measured when low volatile oil was mixed with gasoline. Next, we conducted gasoline vapor absorption experiments using the hybrid combustion inhibitor. We modeled the gasoline vapor absorption behavior by the hybrid combustion inhibitor and derived the vapor absorption coefficient. Furthermore, we conducted combustion suppression experiments for gasoline spills using a hybrid combustion inhibitor, and examined the inflammable effect of the proposed hybrid combustion inhibitor. We confirmed that by spraying the hybrid combustion inhibitor, the gasoline vapor in gas phase was absorbed and the combustion of gasoline vapor was suppressed. It was found that the combustion suppression effect of the hybrid combustion inhibitor can be predicted by using the proposed vapor absorption model.