AbstractAn expression is developed for the friction coefficient of a material in terms of the parameters that control the friction shear. This expression in conjunction with the frictional heating equation describes the hot spot temperature produced in a friction event. Hot spot temperature increases with an increase in the particle size and shear strength of the explosive material, with an increase in the (shock) loading pressure and friction velocity, and with a decrease in material thermal conductivity. The equations are discussed in terms of their implications regarding the factors that control the sensitivity of an explosive or propellant to frictional heating under various conditions, and the results of experimental studies given in the literature.