This International Standard specifies a method for the determination of residual vinyl chloride monomer in homopolymer and copolymer resins of vinyl chloride. The method is based on a static headspace gas-chromatographic technique (i.e. the analysis of the vapour phase in equilibrium with the solid phase at constant temperature) and is suitable for all kinds of homopolymer and copolymer resin. It is done directly on the resin in powder form. For compounded material, granulate, extrudate, films, etc., use ISO 6401. NOTE In the case of compounded material, it is necessary to dissolve the sample in a suitable solvent in order to reach complete headspace equilibrium.