Cooperative Personnel Services Firefighter (CPS) Practice Exam 2025 - Free Firefighter Exam Questions and Study Guide

The correct choice refers to deflagration, which is characterized by a combustion process that occurs at a rate slower than the speed of sound in the surrounding medium. This type of reaction involves a relatively low rate of pressure increase and predominantly involves thermal conduction rather than shock waves.

In deflagration, the heat released by the reaction is conducted through the unburned fuel, allowing the fire to spread through convection and conduction. Typical examples include the burning of solid or liquid fuels in an oxygen-rich atmosphere. This process is generally observed in common fire scenarios, such as house fires and other flames where rapid yet subsonic combustion takes place.

Other terms mentioned in the options describe distinctly different phenomena. Detonation, for instance, involves a supersonic shock wave and occurs with explosive materials, while flashover refers to the sudden spread of fire in an enclosed space when combustible gases reach their ignition temperature. Combustion is a broader term describing any chemical reaction that produces heat and light, encompassing both deflagration and detonation. Understanding these distinctions helps clarify why deflagration is the accurate choice for the described scenario.