The table shows both current and obsolete British EN standard in the 'Status' column. 'C' is current and 'W' is withdrawn. The 'date' is the original publication year. For ASTM standards, the table shows current standards only. ASTM standards are reviewed each year and the status updated, even if no changes have been made to the standard. The original and current year of issue is not therefore shown. In cases of doubt the catalogues maintained by the BS British Standards Institution or the American Society for Testing and Materials should be used.