Sound levels (or sound pressure waves) are measured in decibels and generally using a weighted scale called dB(A). The dB(A) scale is adjusted to take into account the varying sensitivity of the human ear to different frequencies of sound. As a result, very low and very high frequencies are given less ‘weight’ as these frequencies are less likely to cause hearing damage.
Using the dB(A) scale, a quiet room at night will measure around 20 dB(A) while a normal conversation is likely to measure around 60 dB(A).
140dB(A) is considered the extreme threshold of tolerance for a human ear and will cause considerable pain. However, 140dB(A) is not simply 7 times louder than 20dB(A). As the scale is weighted and calculated algorithmically, 140dB(A) actually is around 1,000,000,000,000 times more intense than 20dB(A)! This is because a small increase in the decibel level corresponds to a large increase in intensity, so every 10dB(A) increase means that sound energy increases 10 times.
In the UK workplace, employers have to supply hearing protection where noise is in excess of 80dB(A), but where levels exceed 85dB(A), hearing protection becomes mandatory.
For more information on the Health and Safety Executive regulations on noise exposure in the workplace, please click on the logo below.
At the Leeds Audiology Clinic, we provide custom made hearing protection from a variety of suppliers.
The most basic form of hearing protection is a foam ear defender. Although quite an effective barrier to noise, this style of earplug is only designed for single use due to the possible build-up of dirt and bacteria through repeated handling. Due to its single use, these products can quickly work out as an expensive solution where frequent wearing is required.
A more long-lasting and comfortable earplug is a custom moulded version. These are washable, hard wearing and can be worn for long periods of time without discomfort. There are options of soft silicone or hard acrylic models and these products can be made in a variety of colours including hi-vis. Some models have additional filters to reduce harmful frequencies whilst allowing normal conversations to take place. Attenuation for custom moulded earplugs is generally up 27dB but is frequency specific.
At the Leeds Audiology Clinic we use a variety of manufacturers for our over-the-counter and custom moulded plugs. Please call for more information.
For more information please call 0113 288 0170 or email firstname.lastname@example.org