A purely empirical procedure was presented at the Beijing symposium in 2005 to formulate fire losses based on fire statistics in Japan. The procedure is based on a non-liner soil mechanics formulation called Hardin-Drnevich model, fitting fairly well with the probability of exceedance of monetary loss and floor area damaged by fire observed in a number of types of fire-resistant building. The present paper is intended to summarize recent findings, focusing on factors determining the nonlinear characteristics of the empirical formulation in terms of area damaged by fire within the building of fire origin. First, the applicability of the model is examined for various building types remaining to be addressed. Then, some potential factors are analyzed for their effects on the occurrence of relatively small and more frequent damage. Finally, a more mechanistic model is proposed based on the analysis of timber house fires, relating the risk profile in the vicinity of the extreme with the dimension of properties at risk.