Heat Transfer Analysis

Heat transfer analysis is a critical component of fire analysis and reconstruction. Essentially, heat transfer modeling provides information about the thermal history of an object or a fluid: what temperatures were reached, how long did it take to reach those temperatures, and how long did the temperatures last for. This heat transfer analysis can be used to assess whether component failure is likely, to determine if a particular material or item could have caused a fire, and answer questions related to friction heating, self heating to ignition (spontaneous combustion such as can occur with oil-soaked rags), the effectiveness of insulation materials, or the strength of structural materials (steel, composites) when exposed to high temperatures. A heat transfer analysis may entail analytical “pen and paper” calculations, or detailed finite element/finite volume heat transfer simulation techniques, e.g. using commercial computer codes such as COMSOL. Knowledge and experience are necessary to ensure that the correct heat transfer simulation tool is applied to answer the questions at hand in a cost-effective yet comprehensive manner. As a real-world example of a heat transfer analysis, the sequence of three images below shows time-dependent temperature contours on a vertical wall subject to thermal insult from an exposure fire. This information can then be used to determine when the wall would ignite or fail structurally.