Noise is sound that is loud, unpleasant, unexpected or undesired. Noise is especially dangerous because it interferes with communication and disrupts concentration. Excessively loud and prolonged exposure to noise can be very damaging to hearing. Both the level of noise and the length of exposure to the noise can increase the risk for noise-induced hearing loss.
Noise levels are measured in decibels (dB). The higher the decibel level, the greater the potential for hearing damage, as the hearing system can be injured by excessively loud and sudden events (fireworks, explosions, etc.). Prolonged exposure to high noise levels can lead to gradual hearing loss that is not detected immediately, and sounds that are louder than 85 dB can cause permanent hearing loss.
It is important to review working conditions and identify activities where noise levels will be excessive or prolonged. Proper hearing protection should be selected based on the conditions and suitability to the situation. Hearing protection devices are available to suit most any condition. Manufacturer’s recommendations for use should always be followed.
|Sample Noise Levels|
|Noise||Conversational voices||Idling tractor||Conveyor||Diesel truck||Power lawn mower||Leaf bower||Power tools||Chain saw|
Hearing Protection Options
Not all materials can block the same amount of sound. The manufacturer indicates how much noise (in decibels) the hearing protection device can block if used properly. This is called the noise reduction rating (NRR). For general use, look for an NRR of 25 or greater. The higher the NRR number, the better the protection. In extremely noisy conditions, workers may use multiple devices (both earplugs and earmuffs).
Quality hearing protection devices that are properly fitted are designed to reduce excessive noise levels while maintaining normal hearing abilities, and will not prevent the user from hearing important messages or conversation. There are numerous types and styles available to meet specific user needs and situations. One size does not fit all, so choose a device that provides protection and is comfortable to wear.
Earplugs are devices that are designed to be inserted into the ear canal to provide protection against excessively loud noises. They come in a variety of shapes and sizes, and are often made of foam, silicone, plastic or rubber. Some are formable plugs that must be compressed or shaped prior to insertion. These are typically foam and are considered disposable. Others are preformed plugs made from softer plastics or silicones that use “barbs,” which are contoured to provide a tight fit to the ear canal. But these but must be sized more carefully than the foam type. Custom, premolded earplugs are made of soft, flexible material preformed to fit the ear. They must be fitted (sized) for each ear. These plugs can be reused, but they should be washed after each use. Use premolded plugs when hearing protection is used on a regular basis.
Earmuffs are adjustable headbands with soft cups and cushions that seal around the ear. Earmuffs may be more comfortable to wear over a longer period than plugs. Workers should not wear earmuffs with eyeglasses or any other obstruction if the seal around the ears cannot be maintained. Earmuffs may be the best choice for occasional users of noisy equipment, such as a power lawn mowers or power tools. They are also available with built-in radios and audio connections to allow the user to listen to music or news while working. Just be sure the volume is not so loud to prevent hearing normal sounds and conversations. Workers may wear plugs under earmuffs for additional protection.