The Importance of Hearing Protection
When most people discuss hearing loss prevention, their minds usually drift to loud rock concerts and headphones blasting so loud that people sitting on the other side of the train car can hear them. While these scenarios certainly have the potential to cause harm, the most concerning source of hearing damage occurs where people have little opportunity to avoid it: at the workplace.
The Bureau of Labor Statistics has reported more than 125,000 permanent hearing loss cases stemming from occupational noise hazards in the past decade. 21,000 of these cases came from 2009 alone.
Sadly, many project managers and employees are not aware of the dangerous levels of sound they are exposing themselves to every day. With added awareness and a greater focus on hearing loss prevention and hearing protection, hundreds of thousands of workers will be able to preserve their hearing abilities for many years to come.
What Causes Hearing Loss?
The human ear works by directing sound waves against the eardrum. This organ vibrates, creating a percussive effect that travels through a series of tiny bones called the ossicles and into the cochlea’s organ of Corti.
Inside the organ of Corti lies thousands of tiny hairs attached to nerve endings. As the sound vibrations journey from their exterior source all the way through the inner ear and into the organ of Corti, the microscopic hairs wave and send nerve signals to the brain. According to various factors like frequency, volume and wavelength, the sound will be interpreted by the brain to reveal important information about the listener’s environment.
With noises that exceed certain levels, the sound waves generate so much pressure that they put a huge amount of stress on the inner ear’s hairs. Over time, the nerve endings or the hairs themselves become damaged, and less sound gets through to the brain. People suffering from hearing loss gradually lose their ability to hear certain frequencies until they can barely hear anything at all.
What Noise Levels Cause Damage?
Sound volume levels are essentially a measure of the pressure creating the sound waves, which is measured in decibels (dB). Corresponding scale-adjusted dB levels for common noise sources are as follows:
- 35 dB — Soft whisper
- 50 dB — Urban street noise from inside the home
- 60 dB — Clearly-audible human speech
- 75 dB — Vacuum Cleaner
- 85 dB — Large diesel engine truck
- 95 dB — Jackhammer
- 100 dB — Circular saw
- 110 dB — Night club
- 125 dB — Jet engine
OSHA recommends no more than 8 hours of exposure to 90 dB noises a day for all workers. Increase that number by 5 dBA and the recommended exposure period is cut in half, so workers can listen to 95 dBA noise levels for only 4 hours and 115 dB noise levels for just 15 minutes.
The National Institute for Occupational Safety and Health (NIOSH) is even less forgiving. They recommend no more than 8 hours of exposure per day for sounds at 85 dB, and for every increase in 3 dB the time is cut in half. By this measure, NIOSH would suggest only 15 minutes of exposure a day to 100 dB sounds.
Reducing Noise’s Impact
The most effective means of reducing the level of hearing damage is to use engineered solutions that dampen the noise levels of equipment. Experts also recommend periods of silence following exposure to loud noises so that the hearing organs can recover. Workers ending their period of operating loud equipment should be given tasks far away from the next equipment operator, for instance.
Since these measures are not possible at every job site, hearing protection is recommended. Over-the-ear protective devices or plug-style protection can reduce the impact of loud noise sources significantly.
Ensure that your job site takes measures to both reduce the effect noise sources can have on workers and to provide workers with adequate hearing protection on a daily basis. They will appreciate what you have done for them, and if you follow these guidelines too you will be able to hear them clearly when they say “thank you.”