Fire resistance requirements often influence construction costs significantly. Excessive fire resistance is an unnecessary cost. The recent development of fire safety engineering and the trend toward performance based fire regulations open up new possibilities for optimising building design without compromising safety. This technical report describes a fire safety engineering process for estimating the fire resistance performance of building construction by calculation or test and the appropriate documentation of the assumptions that affect the outcome. The process described represents a standard of care that a professional engineer should use in a design submittal for regulatory review. The process is laid out in terms that are consistent with the accepted practice of fire safety engineering as documented in reports of ISO TC92 SC4, Fire Safety Engineering. The report includes a section on vocabulary to assist in the establishment of a consistent terminology in this area.