This International Standard establishes a general specification for acrylonitrile/styrene (or substituted styrene)/acrylester for pipes and fittings. The values given shall not be used for design purposes. This International Standard does not apply to a) materials containing less than 20 % acrylonitrile in the continuous phase; b) materials containing more than 5 % of another comonomer or polymer in the continuous phase; c) materials containing flame retardants; d) materials containing fibres.