Protective Devices
Protective devices for hearing health and safety are plentiful:
- Over the ear noise protection muffs look like headphones. [View]
- Some models have bluetooth capability making them similar to noise cancelling headphones but with greater sound blocking for harmful noise. [View]
- There are the familiar ear plugs. [View]
- Some ear plugs have intelligent design to block loud noises when safe levels are exceeded. [View]
Harmful Exposure Types
There are a diversity of potentially harmful audio types.
- Intermittent. If you are working on a construction job site, and someone is using a staple gun or hammering, depending on your distance from the sawing and the acoustics in the room, you may be exposed to intermittent harmfully high sounds. These sudden loud sounds can be harmful to the eardrums.
- Harshness. If you are working on a construction job site, and someone is sawing long strips of aluminum with an electric motor powered metal saw, depending on your distance from the sawing and the acoustics in the room, you may be exposed to a type of sound wave that is harsh and raspy. We can see a visual representation of a sound wave using audio equipment. A sawtooth type of sound would modulate harshly in frequency and it has the visual appearance of a saw blade. A smooth sine wave could potentially be less harmful because the waveform is not harsh. This is similar to the difference between fine grain sandpaper and rough grain sandpaper.
- Duration. Being exposed to loud sounds over an extended period of time without rest can be harmful.
- Resonance. Stringed instruments offer a good example of how a note played at one octave can cause strings for the same note to vibrate at other octaves. Similarly, a loud sound at the same frequency of an object, such as a wine glass, could cause damage to that object. It’s like turning up the volume of that object’s vibration. It could break. If a frequency is similar to your ear drum natural vibration frequency range, it could harm your ear drums. For example, unprotected exposure to a jet airplane engine at takeoff could damage the eardrums.
Sound Level dB
For more about sound levels and their potential harm, see the chart provided by the Chemistry department at Purdue. [View Chart]
Document History
This document was originally posted on 21 Jan 2019. It was updated on 4 Aug 2024 to use the WordPress block layout. The original title was: “Noise Level and dB Exposure Charts: How loud is too loud?” The title has been changed to “Noise Level dB Safety.”