Flame propagation refers to the process by which a flame spreads through a combustible material or gas. This occurs when the heat from the flame raises the temperature of nearby fuel to its ignition point, allowing it to catch fire. The speed and manner of this propagation depend on factors like the type of fuel, its concentration, and environmental conditions such as temperature and pressure. In gases, flame propagation can occur in a continuous wave, while in solids, it may involve the burning of surface layers. Understanding flame propagation is crucial for safety in industries involving flammable materials and for designing effective fire prevention systems.