The project is a part of the research programme "Timber constructions and fire" and has been financed by funds from the Swedish Fire Research Board. The aim of the project is to illustrate the possibility of calculating the fire resistance of building panels and wall constructions. The work has been planned in consultation with the steering group "Timber construction and fire" of the Swedish Fire Research Board. The calculations in this work are based on the model developed by the author and presented in [l]. The simulations comprise a total of 23 different calculation cases. The calculations have been compared with experimenrally determined fire resistances in most of the cases. In two cases the influence of a varied opening factor for a fire compartment type A is studied. This document refers to research grants 814-89-1 and 814-89-2 from the Swedish Fire Research Board within the limits of the special programme "Timber constructions and Fire" to the author's company Bedec Engineering. The special programme is a collaboration between the Swedish Fire Research Board, the Swedish Council for Building Research, the Swedish National Board for Technical Development and the Swedish Institute for Wood Technology Research. The author wishes to thank Marianne Abrahamsson who typed the final version of the manuscript and Lewis J Gruber for correction of the English language.