ABSTRACT
Fire or combustion is basically a chemical reaction; more specifically it is a rapid, self-sustaining oxidation process. In order to diagnose fires and explosions, a person must understand the basic chemical and thermodynamic principles involved in the fire process. This chapter discusses the simple combustion of methane and pure oxygen. Besides the heat associated with reactions and combustion processes, a material also contains a certain amount of heat by virtue of its mass and its temperature. For example, a brick at room temperature has obviously less heat in it than a brick that has been baked in an oven at 400°F for an hour or two. In most reference texts, the heat of combustion of a fuel is given as either a higher heating value (HHV) or a lower heating value (LHV). The HHV assumes that the products of combustion have cooled back down to the initial temperature and that the water produced in combustion has condensed to a liquid.
