Healthy human ears can generally hear sound frequencies ranging from 20Hz to 20,000Hz. But hearing loss occurs when sections of the nerves which carry sound information to the brain don’t work in the normal way. Noise-induced hearing loss (NIHL) is generally what occurs from exposure to sounds in the workplace.
Power tools, aeroplane engines or heavy traffic can cause damage to hair cells in the cochlea, which is how hearing can be damaged. This is because over time the hair cells get damaged or broken from sound vibrations, and when enough of them are damaged, loss of hearing occurs.
Sound is measured in decibels (dB). That’s because human ears can register sounds across a wide range of intensities, meaning a linear scale isn’t suitable for sound measurement.
To put this into a real-life context, a whisper is approximately 30 dB, a normal-volume conversation is around 60 dB, and a motorcycle engine is about 95 dB. By attending a live music concert, which is 105 to 110 dB, hearing loss can potentially occur in under five minutes. Therefore, employers must reduce sound levels to around 80 dB.