Hearing protection
Devices of hearing protection are required to reduce the level of noise impacts to or under the permitted level so that warning signals should still remain audible. The level of damage to hearing is 85 dB, but pursuant to a new EU regulation employers are obliged to supply devices of hearing protection over 80 dB.
The capabilities of hearing protection are defined with the use of SNR values. E.g. if the noise level is measured to be 110 dB, devices of noise protection of 26 dB SNR value have to be used to reduce the noise level to the safe 84 value.
To choose the adequate means of hearing protection, it is necessary to know:
- sound pressure level (with respect to change over time/spatial distribution),
- sound pressure levels measured in the 63–8000 Hz measured in the geometric mid-frequency octave scale
Ear plug
- small and light, fills the auditory passage
- comfortable for use with other protective equipment
- soft, not damaging, hygienic, quick, cost-saving solution with the dispenser
- takes longer time to adjust
- less visible for associates
- more difficult to insert and remove
- limited time of usability
- heavier
Ear muffs
- one size fits most of the head sizes
- easy to see from a distance
- smaller dispersion of attenuation
- usable even with minor ear infections
- less comfortable with other protective equipment
- its suitability may be restricted by the given workplace circumstances
- more expensive
Buy only ear muffs that carry permanent indications of:
- name, trademark or other identifying sign of the manufacturer,
- designation of the model,
- for specific wearing positions, the indication of FRONT, UP, LEFT and RIGHT,
- number of the relevant standard.
Devices of hearing protection can be classified into three groups on the basis of the degree of the prevailing noise level:
1. Group: Long-term noise level up to 95 dB – impulse noise up to 100 dB
2. Group: Long-term noise level up to 108 dB – impulse noise up to 120 dB
3. Group: Long-term noise level over 108 dB – impulse noise over 120 dB
Major standards pertaining to personal protective equipment for hearing protection:
| Number of the standard | Designation of the standard |
|---|---|
| MSZ EN 352-1 | Devices of hearing protection General requirements. Part 1: Ear muffs |
| MSZ EN 352-2 | Devices of hearing protection General requirements, Part 2: Ear plugs |
| MSZ EN 352-3 | Devices of hearing protection General requirements. Part 3: Ear muffs mounted on industrial helmets |
For ear plugs designated as "reusable", the recommended method of cleaning has to be defined.
The attenuation value of the ear muffs may be smaller by 5–10 dB in case the user wears thick-framed spectacles.
Electronic ear muffles make low noises audible or amplify them by 12 dB.
Any ear cushion having become inflexible has to be replaced.
When the head strap becomes excessively long, the entire ear muffs has to be replaced.