100 dB (0.002 kPa)

Barely noticeable

110 dB (0.006 kPa)

Readily acceptable. Rattling of loose windows/doors/ceiling panels

128 dB (0.050 kPa)

Currently acceptable by South African authorities as being a reasonable level for public concern. No more than 10% of measurements should exceed this value)

134 dB (0.100 kPa)

§ Limit is 133dB if lower frequency limit of the instrument is 2Hz.

§ Currently accepted by South African authorities that damage will occur below this level. (No measurements should exceed this value outside of the mining boundaries.)

-Good Highveld thunderstorm

140 dB (0.200 kPa)

§ Exceed by strong wind gusts

§ Poorly mounted pictures, rattling of objects on shelves/display units, potential for these to fall

170 dB (6.3 kPa)

Will break a well mounted window