PaulMarcel said:
I generally use the -26db set all the time except when routing, then use the -31db. The -26 are more comfortable.
DISCLAIMER: I'm aware that Paul-Marcel works on his own in his garage, and that his hearing protection allows ambient noise to travel through, but I thought I'd use his SNR values to illustrate that there is such a thing as "over-protection" when it comes to hearing protection. [wink]
In the UK, the Health & Safety Executive recommend that you should aim for between 80 dB and 75 dB at the ear and should avoid protectors resulting in less than 70 dB at the ear as this can lead to unsafe working environments and isolation. (see
http://www.hse.gov.uk/noise/goodpractice/hearingoverprotect.htm)
Of all the tools I own, the TS75 has the highest Sound Pressure Level dB(A) which equates to the noise level measured at the operators ears (of 95 dB). The lowest are my T15 and CXS (a mere 65 dB).
Using more than one tool at once should add no more than about 3 dB to the overall number. TS75 (95 dB) and CTL 26 E (71 dB) works out at 95.01 dB whilst the ETS 150 (72 dB) and CTL Midi (72 dB)work out at 75.01 dB.
So using the "loudest" machine, the TS75 (95 dB) with the CTL 26 E (71 dB) whilst wearing 31 SNR protectors, results in 68 dB at the ear which is slightly below recommendations. At 26 SNR, it's 73 dB at the ear which gives adequate protection and does not "over-protect". But the 26 SNR protectors would result in "over-protection" with some of the quieter tools and a lower SNR may be advisable.
Now obviously "over-protecting" won't damage your
hearing, but outside of the home workshop, it could cause the safety and isolation problems mentioned by the HSE.
Of course, the designs like those that Paul-Marcel uses, that allow sound at safe levels to pass through to the ear canal while reducing potentially harmful noises (above 85dB) change the equation slightly, but not everyone is using those.
Personally, given I work on my own in a small garage and my woodworking is part-time in nature (as the length of time of exposure is also a variable), I like to use different protection depending on the nature of the work. When using tools that can inflict severe physical damage to me in milliseconds (saws, routers etc.) I like to know the tool is on and in use! [scared]
When sanding for longer periods, I like to listen to music instead of the sounds of the tool and extractor. When drilling, I hardly ever have earing protection on unless it's already in place from other operations.
I guess what I'm saying is that one size doesn't always fit all (with regard to SNR level as well as type of protection) and as mentioned earlier in the thread, the best hearing protection is the one you actually wear.
