- Folding head fastener which can be worn under the chin or on the head
- Perfect to be worn sporadically or occasionally
- Weight: 15g
Plug: Polyurethane foam
H High frequency attenuation 25 dB
M Middle frequency attenuation 20 dB
L Low frequency attenuation 19 dB
Noise Regulations require employers to take action about extreme noise at work and reduction in sound levels (attenuation) can be achieved with earplugs.
Sound intensity is measured in decibels (dB). The human ear can register sounds across a huge range of intensities so a linear scale is not suitable for sound measurement. The decibel scale is logarithmic where the sound intensity doubles for every 3 dB increase. An increase of 20 dB would increase the sound intensity by 100. (50 dB is 100 times louder than 30 dB)
The SNR (single number rating) is the system within the European Union to indicate the protection offered by hearing protection. The number is an average dB reduction that can be used to compare hearing protectors. The higher the SNR, the higher the level of noise attenuation provided. To determine the acoustic pressure on the ears, subtract the SNR value from the average measured noise level.
If the noise level is 108 dB and the SNR is 28 then the experienced noise level is 108 – 28 = 80 dB on average.
HML estimates the attenuation by hearing protection in 3 frequency bands. H = High , M = Medium, L = Low