For more than a century, smoke explosions have been documented in the fire service literature.  Yet even with this long history, smoke explosions have received very little attention in the fire research community.  Anecdotal evidence from firefighters have shown a number of overpressure events that cannot be explained as a gas leak or flammable liquids ignition.  Regardless of the label used to describe these events, be it, backdraft, smoke explosion, rich flashover, or delayed flashover, the sudden ignition of flammable gases (created by the fire) that pressurizes the compartment and expels flames from the vents is simply referred to as an overpressure event (OPE).

In this class, we will examine real fire incidents where an OPE has occurred.  We will analyze the common and unique observations that were made both during the events and on videos after the incidence.  This class does not attempt to fit these events into existing descriptions for backdraft, smoke explosion, hot air explosion etc.  Rather, the events are simply referred to as OPEs, described as the rapid expulsion of combustion products from a building or other vessel followed immediately by flames that cannot be explained by the accidental release of flammable gases or the ignition of flammable liquids.  The class will then focus on several research studies on OPEs that demonstrate the common features as well as the uncommon features in experimental OPEs.  Other explosive hazards that are injuring and killing firefighters will be discussed.