Three existing models of upward flame spread were tested against intermediate-scale experiments on a vinyl-ester/glass composite. Characterization of rate of heat release per unit area, needed as input to the models, was obtained at external radiant fluxes below the minimum for ignition by adaptation of a method due to Kulkarni. There are several limitations on the accuracy of the material characterization when applied to composites. Each of the flame spread models has definite limitations as well. Nevertheless, all three models produced predictions of spread behavior in sufficiently quantitative agreement with the experiments that they should prove useful for engineering analyses of flame spread potential.