This International Standard specifies a method for determining the apparent overall density and the apparent core density of cellular plastics and rubbers. If the material to be tested includes skins formed during a moulding/extrusion, the apparent overall density or the apparent core density, or both, can be determined. If the material does not have skins formed during moulding, the term "overall density" is not applicable. For shaped materials, a different method such as buoyancy method may be used.