Do the Fire Regs only apply to CC

Whilst out shopping I noticed what I think was a caravan rally , from my view point it looked like the caravans and tow cars had been shoe horned into their respective pitches. This took my mind back to the CC site rules regarding fire regs and distances between vans. Adjacent walls should be 6mtrs apart and 3mtrs between adjoining surfaces . ( The 3mtr measurement I don't understand , perhaps some one could enlighten me ? )  Why then do other caravan organisations not conform with the said regs ?