Just lately, I've noticed many threads popping up discussing the ratings on earplugs/muffs. I haven't had time - in the last few days - to highlight how these ratings are made, and/or how their accuracy is derived. I've discussed this in detail in the past, so thought it would be better to create a thread with some relevant links.
I was going to post some excerpts, but thought it's probably better to just let you piece it together yourselves.
http://c.ymcdn.com/sites/www.hearin...16_Conference/Presentations/Alberto_Behar.ppt
https://www.etymotic.com/media/publications/erl-0108-2007.pdf
https://www.magidglove.com/nrr_snr_defined.aspx
https://www.shponline.co.uk/hearing-protection-a-how-to-guide-for-those-choosing-ear-defenders/
http://www.hse.gov.uk/foi/internalops/oms/2009/03/om200903app2.pdf
NRR (US) ratings are where most the confusion is derived. It's widely known that these numbers are based on an ideal fit under perfect conditions, so adjustments are often recommended to represent mis-use, bad fits, and factors such as removing the plugs during use (often for conversational purposes). All this can potentially devalue the attenuation, so a standard formula was made to make people aware of what their attenuation might actually be.
I was going to post some excerpts, but thought it's probably better to just let you piece it together yourselves.
http://c.ymcdn.com/sites/www.hearin...16_Conference/Presentations/Alberto_Behar.ppt
https://www.etymotic.com/media/publications/erl-0108-2007.pdf
https://www.magidglove.com/nrr_snr_defined.aspx
https://www.shponline.co.uk/hearing-protection-a-how-to-guide-for-those-choosing-ear-defenders/
http://www.hse.gov.uk/foi/internalops/oms/2009/03/om200903app2.pdf
NRR (US) ratings are where most the confusion is derived. It's widely known that these numbers are based on an ideal fit under perfect conditions, so adjustments are often recommended to represent mis-use, bad fits, and factors such as removing the plugs during use (often for conversational purposes). All this can potentially devalue the attenuation, so a standard formula was made to make people aware of what their attenuation might actually be.