Recent efforts have occurred in the fire investigation community to examine the behaviors of elevated fires and their contribution to large blazes. Lab scale research in the 1980s demonstrated the propensity of these fires to produce high levels of carbon monoxide and identified the ignition behaviors of the vitiated upper layer. Full scale testing of these fires has started but remains limited. A historical review of selected elevated fires demonstrates the threat of death or serious injury these fires pose as well as the difficulties investigators face in accurately identifying their origins. One investigative challenge they pose is the occasional steep, seemingly reversed damage gradient between the room of fire origin and adjacent spaces. Such apparent anomalies can prove vexing to investigators following the commonly accepted methodology of identifying fire origins by moving from areas of lesser to more extensive damage. In the past eighteen months, several, full-scale, elevated fire tests have been conducted attempting to recreate such conditions. In each test, the fires extended into adjacent spaces and burned beyond flashover. Subsequent examinations showed that in each case, the rooms of fire origin received far less damage than adjoining rooms.
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