This is a metric edition of the 1961 revision of this standard, which it now supersedes. It is issued under the authority of the Hardware and Ironmongery Standards Committee and, as part of BSI's programme of metrication, the values in this standard are expressed in metric terms. Nominal bores are in accordance with the recommendations prepared under Technical Committee B/94, Modular Co-ordination in Building, for the metrication of pipe diameters.
For further information on the values given in SI units, reference should be made to BS 3163, 'The International System of units (SI),. The metric diameters given in this standard fall within the limits of tolerance given in the 1967 standard. These limits have been retained herein, expressed in whole millimetres. For the purposes of replacement, the pipes and fittings are thus interchangeable with those manufactured to the 1961 standard.
The 1967 revision was undertaken in order to simplify further the relationship between spun and sand cast pipes. This involved changes in the dimensional tables and the incorporation of an optional pressure test.
As hitherto, the pipes and fittings covered in this standard .are intended for use above ground. For cast iron pipes and fittings suitable for use underground, reference should be made to BS 78*, BS 437t, BS 1130t and BS 1211§.
This standard covers pipes and fittings of one grade only, the 'heavy' and 'extra heavy' grades having been deleted. The option of omitting certain features, such as the spigot bead, and one socket bead on either sand cast or spun pipes, still remains (Types A and B sockets).
Dimensions given in the tables are such that the pipes covered in the standard, manufactured by either process, are interchangeable and can be used with the fittings included. Double socket lengths of pipe have been included and these comply with requirements and tests laid down for the corresponding spigot and socket pipes.
In order to rationalize production and stocking, the range of angles for bends and branches was reduced in the 1967 edition to five (namely 92-1/2°,104°, 112-1/2°, 135° and 157-1/2°).
