This standard specifies a method for the measurement of the thickness of metallic coatings using the X-Rays Light spectrum method. The standard describes the steps for determining the mass per unit area of the coatings by X-Rays fluorescence technology and allows the calculation of the linear thickness of the coatings based on the material density. The method enables simultaneous measurement of the thickness and composition of multiple coatings. Measurement range and uncertainty are affected by analytical instruments and operating procedures. Suitable for accurate measurement of the thickness and composition of metallic coatings.