In a previous study, we proposed a two-dimensional equation to model fire spread. This study was in keeping with our long-term goal to create a forest fire simulator. The model was tested for laboratory fire experiments conducted on pine needle litter and allowed us to exhibit the main features of these fires. The study was carried out for a single fuel load however. The aim of the present paper is to further validate this model. First the influence of fuel load on the model predictions for horizontal fire spread is examined. These results which are in agreement with the experimental data, were then compared to predictions from other physical models. In addition, comparisons are made between numerical and experimental results under slope conditions for line-ignition fires. In this last case, the influence of the fuel load is also considered.