Fundamental experimental analysis of the ignition risk of sparks generated during collisions between small UAV propellers and personal protective equipment

Small unmanned aerial vehicles (UAVs) are increasingly utilized in a variety of environments, including those containing flammable substances, where the risk of ignition is a significant concern. In this study, we investigate the risk of sparks generated by UAV propeller collisions with personal protective gear to ignite these gases. We utilized a high-speed infrared camera to measure the temperatures of sparks produced during such collisions. The experiments involved collisions between various types of protective gear and rotating propellers, during which spark generation was observed upon impact. The high-speed infrared camera recorded the spark temperatures at the moment of impact. The sparks produced by these collision reached temperatures ranging from 375 [°C] and 900 [°C], exceeding the auto-ignition temperatures of hydrogen, diesel oil, and gasoline vapors. Notably, even protective gear that did not produce visible sparks reached temperatures up to 375 [°C], which surpasses the auto-ignition temperatures of some flammable substances, such as gasoline and kerosene. Based on the experimental results, we discuss the potential risks of igniting hydrogen, diesel oil, gasoline, and kerosene due to propeller collisions with protective equipment. •PPE efficacy in reducing injury risk has been studied via collision experiments.•Flammable-substance ignition risk during propeller–PPE collision investigated.•High-speed infrared camera recorded temperature of generated spark during collision.•Ignition risk based on auto-ignition temperatures of flammable substances examined.