Hearing protection devices prevent noise-induced hearing loss by reducing sound levels reaching the ear. These essential safety tools come in various forms and offer different levels of protection based on specific needs and environments.
How Hearing Protection Works
A hearing protection device (HPD) creates a barrier between hazardous noise and the ear canal. When properly fitted, HPDs can reduce noise exposure to safe levels below 85 dBA over an 8-hour workday.
Types of Hearing Protection
Earmuffs Shield External Ear
Earmuffs consist of sound-absorbing foam-lined cups that fit over the outer ears. A headband applies pressure to create an effective seal around the ears. The cups align with the ear canal opening to maximize noise reduction.
Earplugs Block Inner Canal
Earplugs insert directly into the ear canal and come in several varieties:
- Pre-molded plugs have a fixed shape for push-to-fit insertion
- Formable plugs adapt to individual ear canal shapes
- Roll-down foam plugs expand after insertion for a custom seal
- Custom plugs are professionally molded to exact ear dimensions
Electronic Devices Offer Smart Protection
Electronic HPDs use microphones and circuits for active noise cancellation. They can selectively block harmful sounds while allowing speech and important environmental sounds to pass through. These sophisticated devices help workers communicate while staying protected.
Protection Levels and Standards
The Noise Reduction Rating (NRR) measures HPD effectiveness in decibels. However, real-world protection varies significantly from laboratory ratings. NIOSH recommends:
- 70% effectiveness for pre-formed earplugs
- 50% for formable earplugs
- 25% for earmuffs
Proper Use and Maintenance
Clean reusable HPDs regularly with mild soap and warm water. Replace:
- Reusable earplugs every 2-4 weeks
- Earmuff cushions every 3-8 months
- Any damaged protection immediately
When Protection is Required
OSHA mandates hearing protection when noise levels exceed:
- 90 dBA over 8 hours (standard workplace)
- 105 dBA (requires dual protection with both plugs and muffs)
The effectiveness of hearing protection depends heavily on proper fit and consistent use. Individual fit testing and training provide the best protection against noise-induced hearing loss.
The examples and perspective in this article may not represent a worldwide view of the subject. (June 2020) |
A hearing protection device, also known as a HPD, is an ear protection device worn in or over the ears while exposed to hazardous noise and provide hearing protection to help prevent noise-induced hearing loss. HPDs reduce the level of the noise entering the ear. HPDs can also protect against other effects of noise exposure such as tinnitus and hyperacusis. There are many different types of HPDs available for use, including earmuffs, earplugs, electronic hearing protection devices, and semi-insert devices.
The use of the HPD without individual selection, training and fit testing does not significantly reduce the risk of hearing loss. For example, one study covered more than 19 thousand workers, some of whom usually used hearing protective devices, and some did not use them at all. There was no statistically significant difference in the risk of noise-induced hearing loss.