Ahmed ElGhamrawi. Chemical composition. See Full PDF. Download PDF BRITISH STANDARD BS EN Hot finished structural hollow sections of non-alloy and fine grain steels — PartTolerances, dimensions and sectional properties The European Standard EN has the status of a British Standard ICS BS EN specifies the technical delivery conditions for hot finished hollow sections of circular, square, rectangular or elliptical forms and applies to hollow sections formed hot, with or without subsequent heat tre