Noise is a part of everyday life—especially on industrial job sites—but when does sound become a safety hazard? Understanding how noise affects hearing is essential for protecting workers and complying with OSHA standards. Let’s break down the basics of sound intensity, hearing protection, and what your workplace needs to stay safe and compliant.
What Is a Decibel (dB)?
The decibel (dB) is the unit used to measure the intensity of sound. It’s not a linear scale—every increase of 3 dB actually doubles the amount of sound energy. That means even small increases in dB can have a big impact on your ears.
To give you an idea:
- 85–95 dB is the threshold of discomfort
- 120–140 dB is the threshold of pain
How Does Noise Cause Hearing Damage?
Hearing damage isn’t just about volume—it’s also about how long you’re exposed to loud sounds and your personal susceptibility. Still, there’s a clear line: regular exposure to noise above 85 dB can lead to permanent hearing loss.
OSHA’s Noise Exposure Standards
OSHA (Occupational Safety and Health Administration) requires employers to implement a Hearing Protection Program (HPP) when noise exposure exceeds 85 dB. Here’s what that includes:
- Limit exposure to no more than an average of 90 dB over an 8-hour shift
- For every 5 dB increase in noise, the permissible exposure time is cut in half
To manage that, employers must:
- Offer at least three styles of hearing protection (e.g., earplugs, earmuffs, custom molds)
- Use engineering controls to reduce noise at the source
- Limit time employees spend in high-noise areas
- Provide annual hearing tests for affected workers
What Is Noise Reduction Rating (NRR)?
The Noise Reduction Rating (NRR) tells you how much sound a hearing protection device (HPD) can block, measured in dB under ideal conditions. For example, if earplugs have an NRR of 32, they can block up to 32 dB of noise in a lab setting.
But real life isn’t a lab. OSHA adjusts for this using the formula:
Adjusted NRR = NRR – 7
So, an NRR of 32 becomes an adjusted NRR of 25 dB—a more realistic estimate of actual protection on the job.
Final Thoughts
Protecting hearing isn’t just about avoiding discomfort—it’s about long-term health, safety, and compliance. By understanding how sound works, recognizing the signs of overexposure, and implementing OSHA-compliant protection programs, employers can help ensure their teams stay safe—and sound—for years to come.
Browse our hearing protection products HERE.
To learn more about types of hearing protection devices, visit our related blog post.
Are you a visual learner? Watch our webinar on Hearing Conservation HERE.
