If we are not hearing-impaired, the sounds we hear are vibrations in air. In addition to Tim Chin's answer, the BCAPL rulebook includes the 5 second rule. But when these pools are above inhabitable space, the noise and vibration at pool level needs to be. But when these pools are above inhabitable space, the noise and vibration at pool level needs to be. Bearing of Swimming Pools at the Villa Aurea, Lochau.