>>Standard football pressure is around 13psid - cabin pressure at SL is about 14.7 psi and at 8000' cabin altitude about 10psi - so there's only an extra 4-5 odd psi on a football that's designed to take 28psi (absolute).
>>I may have got diff and abs confused there, apologies. But it's not a big difference anyway, IMHO.
>>In any case, like balloons, if a football did burst it wouldn't explode outwards like a bomb - if you watch high-speed film of balloons bursting, the failure begins with a small rip or hole and the skin retracts along itself, not expanding outwards.
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Woa there. If a gauge measures 13 psi within the football this is in addition to 14.7 psi atmospheric. Where do you get the 28 psi 'absolute figure from (and how would you measure it - in a vacuum?)?
Balloons retract because they are elastically stretched when inflated. Puncturing them releases the forces keeping the balloon stretched, so it implodes. A football tends to be rigid (within limits) and so explosive destruction could propel pieces outwards as the internal pressure escapes. It's the principle of a bomb . . .