This International Standard specifies two calcination methods for the determination of the textile glass and mineral filler content of glass-reinforced plastics: Method A: for the determination of the textile glass content when no mineral fillers are present. Method B: for the determination of the textile-glass and mineral-filler content when both components are present. This International Standard is applicable to the following types of material: Prepregs made from yarns, rovings, tapes or fabrics; SMC, BMC and DMC moulding compounds; textile-glass-reinforced thermoplastic moulding materials and granules; filled or unfilled textile-glass laminates made with thermosetting or thermoplastic resins. The methods are not applicable to the following types of reinforced plastic: those containing reinforcements other than textile glass; those containing materials which do not completely burn off at the test temperature (for example, those based on silicone resin); those containing mineral fillers which degrade at temperatures below the minimum calcination temperature. For these materials, ISO 11667, Fibre-reinforced plastics - Moulding compounds and prepregs -Determination of resin, reinforcement-fibre and mineral-filler content - Dissolution method, may be used.