BS 21:1985
Specification for pipe threads for tubes and fittings where pressure-tight joints are made on the threads (metric dimensions)
https://doi.org/10.3403/00141824 (published 30/09/1985)
BS 21:1985 is maintained by ISE/110. This standard is available from the following sources:
Other historical versions of this standard document also exist:
- BS 21:1973 [current until 30/09/1985]
- BS 21:1938 [current until 31/12/1957]
- BS 21:1909 [current until 01/11/1938]
- BS 21:1905 [current until 01/11/1909]