This report documents a number of changes to the 1992 release of the Canadian Forest Fire Behavior Prediction (FBP) System, and addresses several mathematical and physical inconsistencies in its underlying models that have been identified over the last 15 years of its operational use throughout Canada. Several additional equations are included to allow calculations of a few elements not included in the original release of the system. However, these updates and revisions do not represent significant changes to the structure of the FBP System, but are largely modifications and clarifications of some of the models within the system. The implementation of these mathematical changes to the FBP System into existing technology transfer products (e.g., field guides and aids, software products), should be virtually transparent to most users. Finally, 20 formal test cases are presented to allow the developers of applications based on the FBP System to test their products against known benchmarks. It is important to understand that this document does not represent a new version of the Canadian FBP System (described in ST-X-3 'The Development and Structure of the Canadian Forest Fire Behavior System'), but is rather a supplement to that publication. A correct and up-to-date implementation of the FBP System must rely on the information contained in both these reports.

[This publication is referenced in the "Synthesis of knowledge of extreme fire behavior: volume I for fire managers" (Werth et al 2011).]