What’s wrong with BS 373:1957?

Sadly, British Standard 373:1957 “Methods of testing small clear specimens of timber” probably won’t get to see it’s 60th birthday due to a rather critical error in the equations for calculating the Modulus of Elasticity from bending tests.  The 1957 edition of the standard was correct, but somewhere along the line the equations got corrupted.
Since the original 1957 publication, the standard has been reformatted. The content has not supposed to have been changed (why it still carries the 1957 date) – but mistakes were made in the copying of equations.  The current printing carries a 1999 copyright date so the equations have been wrong for at least a decade and a half.  It is perhaps because these equations are so familiar to engineers that nobody noticed that the beam depth with written with an exponent of 2 rather than a 3.

Original 1957 issue (from Appendix A)

BS3737 original

Current issue (1999 imprint)

BS3737 current

British Standards Committee B/518 will now look at a revision.

Update 10 April 2024: Not only did BS 373:1957 make it to its 60th birthday despite the error, it looks like it might even make the 70th! It’s a good job the people that use this standard know their engineering mechanics theory. But yeah… should still be fixed. If you are using BSOL (British Standards Online) quick view you probably also see an even more incorrect equation due to technical glitches with how older standards render in the viewer.

Original (correct) formatting is:

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