Heat for Pre-ignition and Flames

In this chapter of our book, Fire science from chemistry to landscape management, we explain the factors that influence the energy associated with the pre-ignition phase and the estimation of the adiabatic flame temperature. Before fuels can ignite, they go through a pre-ignition phase that removes water and other liquid volatile compounds from the fuel through dehydration and distillation and that heats the fuel up to the ignition temperature. The required energy is termed heat of pre-ignition as it is the energy required for raising the temperature of the fuel from ambient to the ignition temperature. In this chapter, we discuss estimating the heat of pre-ignition. Then, we estimate the adiabatic flame temperature using the low heat of combustion and the specific heat capacity. The interactive spreadsheet is useful for graphically visualizing how fuel moisture and other fuel characteristics affect the energy required for ignition. In subsequent chapters, we address the implications of heat from fires for the spread and intensity of flaming and smoldering combustion, and for the survival and recovery of plants, people, and ecosystem processes in forests, woodlands, shrublands, and grasslands throughout the world.