Requirements for manufacture and testing of steel vessels for use in systems operating with any maximum working pressure up to 10 bar.Cross References:BS 21BS 1387BS 1449:Part 1BS 1449:Part 2BS 1501:Part 1BS 4814BS 4870:Part 1BS 4871:Part 1BS 5135BS 5169BS 5500BS 5750BS 6001BS AU 50:Part 3EEC Directive L229:1980UK Water Fittings Bye-laws Scheme Information and Guidance Note No. 5-01-02