Hearing Protection at Work: Why Choose with Precision?
Continuous noise in the workplace is one of the most insidious occupational hazards. Noise-Induced Hearing Loss (NIHL) is painless, bloodless, and clinically irreversible. The hair cells of the inner ear destroyed by excessive sound pressure levels do not regenerate.
To protect workers in metallurgy, metalworking, civil construction, the glass industry, and carpentry, choosing the right ear protector is essential. However, choosing does not simply mean buying the protector with the highest possible reduction value.
In this technical guide, JCR explains what the SNR rating is, how to interpret Portuguese legislation, and how to choose between earplugs and earmuffs.
1. What the Portuguese Law States (Decree-Law no. 182/2006)?
National legislation establishes very clear action thresholds regarding daily noise exposure:
- Lower Action Level (80 dB(A)): The employer is obligated to provide suitable hearing protectors to all exposed employees, as well as to promote awareness-raising actions.
- Upper Action Level (85 dB(A)): The use of hearing protection becomes legally mandatory, and the workplace must be clearly marked and delimited.
- Exposure Limit Value (87 dB(A)): The maximum level that may under no circumstances be exceeded at the worker's eardrum, already taking into account the attenuation provided by the ear protector.
2. What is the SNR Value (Single Number Rating)?
The SNR is the standard European index that measures the overall attenuation capacity of an acoustic protector, expressed in decibels (dB).
How to calculate residual noise in the ear:
If the workstation has a measured average noise level of 100 dB(A) and the operator uses an earmuff with SNR 30 dB: Effective Noise = 100 - 30 = 70 dB(A)
The Comfort Zone Rule:
- Below 70 dB(A) — Overprotection (Dangerous): If the protector attenuates sound too much, the worker becomes isolated from the surrounding environment, unable to hear warnings from colleagues, forklift horns, or emergency alarms. The natural tendency is to remove the protector, leaving them unprotected.
- Between 70 and 80 dB(A) — Ideal Comfort Zone: Perfectly safe level with preserved hearing.
- Above 85 dB(A) — Insufficient Protection: Imminent risk of medium-term hearing loss.
3. Earplugs vs. Earmuffs: Which to Choose?
| Feature | Earplugs (Foam / Silicone) | Earmuffs (Passive / Electronic) |
|---|---|---|
| Type of Use | Continuous throughout the entire work shift. | Intermittent (frequent entry and exit from the noise zone). |
| Thermal Comfort | Excellent for hot and humid environments. | Can cause ears to warm up in the summer. |
| Compatibility | Perfect with glasses, masks, and hard hats. | Require helmet-mounted models or neckband designs. |
| Hygiene | Disposable or washable reusable with cord. | Easy-to-clean cushions and hygienic replacement kits. |
| Ease of Fitting | Requires correct compression and insertion technique. | Immediate placement and intuitive adjustment. |
4. Advanced Technologies: Earmuffs with Active Communication
In teamwork or heavy machinery operation tasks, smart earmuffs featuring Bluetooth communication and level-dependent attenuation (such as 3M Peltor solutions) make it possible to attenuate harmful impact noises (gunshots, presses, hammers) while amplifying the human voice and essential ambient sounds.
Explore the Hearing Protection and Earmuffs solutions at JCR to equip your team with solutions tested and certified to EN 352-1 and EN 352-2 standards.
