In the previous report[1], we have already presented a model on fire spread in small scale buildings which are in fear of being wholly involved in fire from the early stage because of their smallness.

The previous model was, however, somewhat insufficient and apart from actual fire in some points, so in this report we present a little more improved model.

The chief improved points of the new model are

a)	experimental data of burning rate are directly substituted in the burning rate in the model i.e. Mp'i in Fig. 1 whose value was unreasonably large in the old model because it was calculated by mechanical application of the virtual point heat source fire plume model.
b)	a model of air entrainment into hot gas door jet has been introduced.
c)	expression of heat of combustion has been changed by separating the heat into the latent heat of pyrolysis and the heat of gaseous phase combustion. and
d)	model of thermal radiation heat transfer has been improved by using Net-radiation method so that we can calculate the heat transfer even when the hot gas layer is nonblack.

In this report, some of the results of the computer simulations based on the new model to investigate into the physical propensities of dwelling fire and the results of the model experiments to verify the model are briefly described as well.