What does the term "hypergolic" refer to in fire fighting terminology?

The term "hypergolic" refers to substances that ignite spontaneously when they come into contact with each other without any external ignition source. This characteristic makes hypergolic propellants particularly significant in fire fighting, especially when dealing with specific fuels used in aircraft that may contain hypergolic elements. Understanding how hypergolic materials behave is crucial for firefighters, as they can result in unexpected ignition scenarios that require specialized handling and extinguishing strategies. While the other options pertain to different aspects of fire fighting, the definition of hypergolic is specific to its ignitability and is crucial for effectively managing fires involving these types of substances.