BS 449 was first issued in 1932 and was revised in December 1935, July 1937, July 1948 and May 1959. It was reset and reprinted in February 1965 incorporating amendments Nos. 1 to 5 and reprinted in October 1967 incorporating amendments Nos. 6 and 7.
When a programme of Codes of Practice for Buildings was drawn up in 1942 under the aegis of the Ministry of Works, a Code of Practice for the structural use of steel in buildings was included in a series for all types of building construction: this was later (194B) issued as CP 113. Much of the information given in BS 449 and in CP 113 was the same and with the formation of the Codes of Practice Council within BSI it was decided that the two documents should be amalgamated and issued as a single publication under the main reference BS 449.
Part 2 of this standard has been prepared, in accordance with the change to the metric system in the construction industry, giving values in terms of SI units. For further information on SI units, reference should be made to BS 3763, ‘International System (SI) units' and PD 5686, ‘The use of SI units '.
The values given in Part 2 represent the equivalents of the values in imperial units in BS 449 : .1959, rounded to convenient numbers. Although the values are not exact equivalents of the imperial ones, Part " 2 does not constitute a technical revision of the standard and is' substantially similar in content to BS 449 : 959.
Amendment SEp No. 8 (AMD 94) published 12th September, 1968 introduced into this standard the use of steels complying to BS 4360, 'Weldable structural steels' superseding the requirements of 13S 15,BS 968 and BS 2762.
This amendment slip also noted the future insertion of grade 55 steel. Part 2 has now been expanded to include the use of this steel, and also includes an amendment to Subclause 3a, Amendment Slip "No. 6 (PD 5854) published 29th June, 1966 revised Subclause 3a and introduced into this standard, precautions against brittle fracture. This subclause on brittle fracture has now been further extended to be in parity with BS 4360. Because of the extent of the amendments made necessary by the publication of BS 4360 it has been found more practical to reissue the imperial edition of this standard incorporating these amendments rather than to publish a further amendment slip.
This imperial edition, which will be issued as Part 1, is now in the course of preparation.
For the purpose of compliance with this standard designers may use the values given in either BS 449 : 1959 or. this part, provided that one set of values is used consistently throughout the design of each part of a structure. A revision of this standard is currently in haud and the revised standard will be written in terms of SI units only.
Users of this British Standard should satisfy themselves that effective compliance is secured with local bye-laws and regulations and, for insurance purposes, with any requirements of insurance companies. The attention of users is also called to the importance of making provision, where necessary, for water, gas, electricity and other services, having particular regard to condition 5 in Clause 21 for cased beams and to condition 4 in Subc1ause 30b for cased struts.
This standard reflects the revised increased yield strength of grade 43 steels included in BS 4360.
