The purpose of this standard is to specify a method for determining the flash and combustion points of petroleum products, using the Cleveland open cup apparatus. It is applicable to all petroleum products with the exception of fuel oils and products whose flash point (determined according to this method) is less than 79 °C. NOTE- Attention must be drawn to the alternative method specified in the UNE 51-022 standard "Petroleum products. Determination of the flash point. Pensky-Martens method in closed glass". This last method is recommended for determining the flash point of fuel oils and should be used when you want to detect the possible presence of weak but significant concentrations of products with low flash points, which may escape detection when using the method specified in this standard.