Specifies the majority of tolerances on dimensions used by ISO/TC 5/SC 1 in drawing up International Standards concerning steel tubes. Is intended for use as a basic document by all ISO technical committees concerned with the standardization of steel tubes. It cannot, therefore, be used as a standard for the definiton of a product. This second edition cancels and replaces the first edition (1977), the standardized tolerances on thickness of which have been technically revised.