From Louie Gregg
Clive Semmens is right to criticise (1 November, p 21) Tony Budd’s calculation of the risk of a “once in 100 years” event occurring within 60 years (18 October, p 20). But he falls into the same trap himself, ignoring the odds of a building blowing down more than once in the same year. The risk over the building’s lifetime is in fact 1 – e-60/100, which is 45.12 per cent – not hugely different from Semmens’s 45.28 per cent, but theoretically important.
Sale, Greater Manchester, UK
