What are flash fires?

Flash fires are characterized as combustion events that ignite and spread rapidly following immediate exposure to an ignition source. This definition aligns with the nature of flash fires, which can occur in a variety of environments where flammable vapors or gases are present. When these materials come into contact with an ignition source, they can combust almost instantaneously, leading to a brief but intense fire.

The other options do not accurately capture the essence of flash fires. While rapid combustion might lead to explosions, it does not specifically define the instant ignition characteristic of flash fires. Colored flames used for signaling are unrelated to the concept of fires and their dynamics. Similarly, combustion events where ignition is delayed describe a different scenario entirely, which does not occur in flash fires, where ignition is immediate. Understanding these distinctions is crucial for recognizing and mitigating the risks associated with flash fires in various settings.