Information for SuperBeam users:

The future of BS449

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BS449 v. BS5950

In the past we have occasionally been contacted when an over zealous building control officer has told a SuperBeam user that calculations to BS449 are no longer acceptable and BS5950 should be used instead. With the introduction of the new Part A Approved Document on 1st December 2004 we have had quite a few phone calls on this subject.

Whilst having a long overdue purge of old magazines and papers I came across this announcement on p.28 of BSI News, August 1992:

"Following the widespread concern over the proposal to declare BS 449: Part 2: 1969 'obsolescent', Sub-committee B/525/31 (formerly CSB/27) has decided not to proceed further with the implementation of this action at this time and the standard maintains its present status.In coming to their decision, the members of Sub-committee B/525/31 were mindful of the fact that BS449: Part 2: 1969 continues to be used by engineers and is a standard referred to in Approved Document A to Building Regulations. The Sub-committee conforms to the policy view of BSI that its future work lies with the development of Eurocodes and supporting standards."

- 15 years on, the definitive Eurocodes and supporting National Annexes are just starting to appear, whilst BS449 Part 2 is listed in the April 2007 BSI catalogue as "current, proposed for confirmation, partially replaced" - £162 (!!) if you're not a BSI member! BSI website

In the 2004 Part A Approved Document (available as a free download from the ODPM web site, in force from 1 December 2004), BS449 is no longer listed as an approved code. Replacing BS449 with BS5950 within SuperBeam with would mean that in many cases (e.g. a loft conversion ridge beam bearing on a timber post) limit-state and permissible stress calculations would be intermixed in the same set of calculations - something less than desirable. We pointed this out to ODPM last year, and their response was to confirm that the fact that a code does not appear in the Part A Approved Document does not mean that it cannot be used, and that the continued use of BS449 in domestic scale structural calculations would not necessarily be impermissible. To quote the new Part A AD "There is no obligation to adopt any particular solution contained in an Approved Document if you prefer to meet the relevant requirements in some other way".

In 'Structural Engineer' 15 March 2005, p.38 includes a letter from Geoff Harding of ODPM: "... Regarding the use of withdrawn Codes, building control authorities will need to be satisfied that such documents continue to provide satisfactory guidance for any structures under consideration. In this context reference should be made to the safety aspects given in paragraph 0.2 on page 6 of the AD.
In the case of BS449 its recommendations were considerably enhanced by amendment No. 8 prior to the document being declared obsolete several years ago. The Code will therefore no doubt continue to provide satisfactory guidance at least for the design of simple beams and other minor works.

When all the relevant supporting information is available we plan to to introduce EuroBeam™, a SuperBeam derived program based on Eurocodes EC3 and EC5 - see the Eurocodes Expert site for more information on the introduction of Eurocodes. When we reach this stage we will of course follow our usual practice and offer deep discounts to existing users. As to when we will be able to do this, who knows? The latest information (from access-steel.com is that the UK EC3 National Annexe will not now be published until later in 2007.

In the meantime we would hope that Building Control checking engineers will accept that it is better to continue to use BS449 for structures such as loft conversions that involve an intimate mix of steel and timber structural elements, and not unreasonable to use this code for simple steelwork calculations in domestic scale structures. For other work we would agree that BS5950, on which our ProSteel program is based, is the better code to use. Registered users of SuperBeam can now buy ProSteel for just £100+VAT

Tony Bryer, Survey Design Associates Limited

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Top Last revised 18 April 2007