This European Standard describes a test method for the determination of the burning behaviour of dust layers under defined initial conditions of air flow, temperature and ignition. A test result of burning class 1 with the described method does not mean that a dust cannot be ignited when dispersed in a cloud. This method is not suitable for use with recognized explosives, like gunpowder and dynamite, explosives which do not require oxygen for combustion, pyrophoric substances, or substances or mixtures of substances which may under some circumstances behave in a similar manner. Expert advice should be called in, when any doubt exists about the existence of hazard due to explosive properties.