This document specifies a method to determine the tendency of a propellant to undergo transition from deflagration to detonation (DDT). It applies to propellants of a grain size up to 8 mm. This method does not apply to black powder and rocket propellant. NOTE 1 Due to the nature of the shape of grains (heterogeneous), the combustion of the rocket propellant can cause a crack of the grain causing an explosion of the rocket motor. NOTE 2 Black powders properties differ significantly from propellant and explosives because black powders are capable of maintaining stable combustion at high velocities without experiencing deflagration detonation transition.