A method for measuring the thermal radiative protection of actual fire fighters garments to an incident radiative heat flux of 8.4 kW/m2 is described. Typical results obtained with several conventional and prototype garments are presented. These results indicate the time to pain, and second degree burn as well as the pain alarm time. The thermal inertia of the garments is also measured based upon burn exposure time. Differences in physical properties such as garment thickness, total weight and number of layers are examined in order to establish the existence of any correlations.