AbstractAmong the various methods for predicting the development of a fire in real conditions we have chosen the one which works on a small‐scale model. The differences in gas concentrations, available fuel, and convection and heat transfer are recognized and discussed. A small‐scale model has been built in which any oxygen concentration, heat flux and air supply can be reproduced simultaneously. The method makes it possible to simulate a good range of conditions, and by controlling these conditions a better knowledge of the geometric reduction which is to be used in the smallscale model can be obtai