Fire Safety Science Digital Archive

A numerical method is presented to determine the thermal conductivity of homogeneous insulation material using boundary temperature measurements. In this inverse analysis the direct problem consists of non-linear partial differential equation that is semidiscretized via the variational form of the heat conduction problem. The inverse problem is reduced to minimization of a regularized functional of residuals solved by numerical gradient methods. Tikhonov and mesh coarsing regularizations are used. This method is known as the Regularized Output Least Squares Method (RLS). The accuracy of the predicted results is examined from an illustrated I-D case of a fire protected steel plate. Transient test temperature of the steel plate is simulated. Noise of randomly varying amplitude is added to the simulated temperature. Results chow that good estimations on the thermal conductivity can be obtained without measuring temperature inside the insulation material. Comparisons with the accuracy of technique used in methods NT FIRE 021 and Pr ENV YYY5-4 of fire protected steel structures are presented.