The article presents the principles of load testing of a firebox taken to calculate it reduction, in cases other than those provided for in PN-B-02852:2001. In addition, examples of conducting proceedings are given to reduce the fire load for calculations in cases other than provided for by the standard. For this purpose, it was used own methods based on determination of fire development. It was assumed that the condition of applying corrective coefficients is lack combustion development deep into the material. The obtained results justify application of decreasing factors in calculations fire load density. The method presented in the article it can be used to take into account the load reduction in cases other than those provided for by the standard.
Keywords: reaction to fire; fire safety; tests of materials; classification; fire load.