GTIMK4
New member
OK - this is a HUGE post, but since I was trying to answer this same question on another board, I figure I'd just copy and post for your info.
I use the 3M 1100 cordless plugs. You should be able to get these at any Acklands or Unisource outlet in your area.
There is a LOT of good info about sound deadening ratings and how they are calculated on the links contained in the page below:
[I had to kill the link because it was screwing up the entire page]
*******************
Here is some excellent info on a how much we are exposed to while riding and wearing a full face helmet:
http://www.isvr.co.uk/at_work/m_cycle.htm
"Noise levels under motorcycle helmets
Noise levels under motorcycle helmets can be very high. Above about 65 km/h or 40 mph the wind noise generated by the airflow over a motorcycle and rider exceeds the noise from the motorcycle itself. Daily noise exposures of working motorcyclists may regularly exceed 90 dB(A).
We have measured noise levels at the ears of police motorcyclists in a wind tunnel and on the road, with several different helmets and motorcycles. Noise levels in the wind tunnel were similar to those on the road.
The graph above shows some examples of noise levels measured under motorcycle helmets during our tests on the roads. Although both BMW motorcycles were ridden by the same person wearing the same helmet, the noise levels differed. The BMW 1100LT has a windscreen which can be raised and lowered, and the noise levels varied with the height of the windscreen. The Kawasaki was ridden by a different person with a different helmet.
The measurements in the wind tunnel showed the main source of noise to be the turbulence at the edge of the windscreen's wake acting on the helmet. The rank ordering of helmets by the noise level depended upon the motorcycle and in particular the windscreen height - a helmet which is relatively quiet on one motorcycle can be relatively noisy on another and vice-versa. Low windscreens direct the turbulence to the base of the helmet, and modifications to improve the helmet seal around the neck can reduce noise levels on motorcycles with low windscreens. High windscreens direct the turbulence to the helmet visor and forehead, and modifications to improve the sealing of the visor to the helmet shell are then effective. Such simple modifications to helmets can reduce noise levels by 5 to 8 dB at the ear.
Wind tunnel tests with a flying helmet containing active noise reduction earmuffs demonstrated that noise levels as low as 70 dB(A) at 80 km/h and 80 dB(A) at 115 km/h were achievable at the ear. Similar systems within a motorcyclist's helmet suggest that this potential will not be realised unless the earmuffs are well isolated from the helmet shell and liner. Another method of achieving similarly low levels is to wear good earplugs. Many police forces in the UK are now providing these for their motorcyclists.
If you ride a motorcycle and your hearing sounds muffled afterwards, or if your ears ring, then you are suffering temporary hearing damage, which, if repeated regularly, may become permanent hearing damage. We recommend you consider wearing earplugs under the helmet. Because the earplugs reduce the noise, you may seem to be travelling more slowly, so take extra care to check your speed until you get used to the earplugs.
This project was carried out for the Home Office by ISVR Consultancy Services, the Department of Aeronautics and Astronautics, the Wolfson Unit for Marine Technology and Industrial Dynamics, and Hampshire Constabulary.
We have also measured the noise exposures of motorcycle patrols for one of the motorist breakdown rescue services. The measurements were carried out during the motorcyclists' normal duties to determine whether their full-day noise exposures were below the limits of the UK Noise at Work Regulations.
References in the open literature:
M.C. Lower, D.W. Hurst, A.R. Claughton and A. Thomas, 1994; Sources and levels of noise under motorcyclists' helmets. Proceedings of the Institute of Acoustics, 16, pt 2, 319-326. ISBN 1 873082 59 2.
M.C. Lower, D.W. Hurst and A. Thomas, 1996; Noise levels and noise reduction under motorcycle helmets. Proceedings of Internoise '96, Book 2, 979 - 982.
**********************************************
Here is a chart signifying what are the max "allowable" values and what are the values we encounter on a day to day basis. Note - when it says motorcycle, that doesn't mean inside the helmet at speed, as it does on the above post.
http://www.headwize.com/articles/hearing_art.htm
90 dbA 8 hrs
92 dbA 6 hrs
95 dbA 4 hrs
97 dbA 3 hrs
100 dbA 2 hrs
102 dbA 1.5 hrs
105 dbA 1 hr
110 dbA 0.5 hr
115 dbA 0.25 hr or less
Note: When the daily noise exposure is composed of two or
more periods of noise exposure of different levels, their combined
effect should be considered, rather than the individual effect of
each. Exposure to impulsive or impact noise should not exceed
140 dB peak sound pressure level.
Figure 2: OSHA Regulation 1910.95 - Occupational noise exposure
As seen in the OSHA Noise Exposure table in figure 2, the louder the sound, the less time it takes for damage to occur. OSHA limits noise exposure levels in the work environment to about 90dB for an 8-hour period, but permits exposure to higher levels for short periods. Many experts believe that the OSHA numbers are too high for hearing safety. EU countries have very strict laws about noise exposure. For example, U.K. employers must take action at two levels of noise exposure: 85dB and 90dB. At 85dB, employers must offer hearing protection and hearing education to employees. At 90dB or higher, employees MUST wear earplugs, and the employer MUST try to reduce the ambient noise level.
60 dB Everyday conversation, ringing telephone.
70 dB Restaurant.
80 dB Heavy city traffic, alarm clock at 2 feet, factory noise, vacuum cleaner, garbage disposal.
90 dB Subway trains, motorcycle, workshop tools, lawn mower.
100 dB Chain saw, pneumatic drill.
110 dB Dance club.
120 dB Rock concert speaker sound, sandblasting, thunderclap.
130 dB Jet take off, gunfire.
Figure 3: Decibel levels of common sounds.
**************************************8
SO WHAT DOES THIS ALL MEAN:
If an ear plug (like the ones I posted above) are rated for 29 dBA then you -7 from that and divide by 2. You get that number, which is about 11dB and you subtract it from the noise level.
SO - if it is 100dB inside the helmet and you subtract 11 dB then you are actually exposed to 89dB.
Since 89 is the UPPER limit of exposure, you might want to consider ALWAYS wearing earplugs.
I use the 3M 1100 cordless plugs. You should be able to get these at any Acklands or Unisource outlet in your area.
There is a LOT of good info about sound deadening ratings and how they are calculated on the links contained in the page below:
[I had to kill the link because it was screwing up the entire page]
*******************
Here is some excellent info on a how much we are exposed to while riding and wearing a full face helmet:
http://www.isvr.co.uk/at_work/m_cycle.htm
"Noise levels under motorcycle helmets
Noise levels under motorcycle helmets can be very high. Above about 65 km/h or 40 mph the wind noise generated by the airflow over a motorcycle and rider exceeds the noise from the motorcycle itself. Daily noise exposures of working motorcyclists may regularly exceed 90 dB(A).
We have measured noise levels at the ears of police motorcyclists in a wind tunnel and on the road, with several different helmets and motorcycles. Noise levels in the wind tunnel were similar to those on the road.
The graph above shows some examples of noise levels measured under motorcycle helmets during our tests on the roads. Although both BMW motorcycles were ridden by the same person wearing the same helmet, the noise levels differed. The BMW 1100LT has a windscreen which can be raised and lowered, and the noise levels varied with the height of the windscreen. The Kawasaki was ridden by a different person with a different helmet.
The measurements in the wind tunnel showed the main source of noise to be the turbulence at the edge of the windscreen's wake acting on the helmet. The rank ordering of helmets by the noise level depended upon the motorcycle and in particular the windscreen height - a helmet which is relatively quiet on one motorcycle can be relatively noisy on another and vice-versa. Low windscreens direct the turbulence to the base of the helmet, and modifications to improve the helmet seal around the neck can reduce noise levels on motorcycles with low windscreens. High windscreens direct the turbulence to the helmet visor and forehead, and modifications to improve the sealing of the visor to the helmet shell are then effective. Such simple modifications to helmets can reduce noise levels by 5 to 8 dB at the ear.
Wind tunnel tests with a flying helmet containing active noise reduction earmuffs demonstrated that noise levels as low as 70 dB(A) at 80 km/h and 80 dB(A) at 115 km/h were achievable at the ear. Similar systems within a motorcyclist's helmet suggest that this potential will not be realised unless the earmuffs are well isolated from the helmet shell and liner. Another method of achieving similarly low levels is to wear good earplugs. Many police forces in the UK are now providing these for their motorcyclists.
If you ride a motorcycle and your hearing sounds muffled afterwards, or if your ears ring, then you are suffering temporary hearing damage, which, if repeated regularly, may become permanent hearing damage. We recommend you consider wearing earplugs under the helmet. Because the earplugs reduce the noise, you may seem to be travelling more slowly, so take extra care to check your speed until you get used to the earplugs.
This project was carried out for the Home Office by ISVR Consultancy Services, the Department of Aeronautics and Astronautics, the Wolfson Unit for Marine Technology and Industrial Dynamics, and Hampshire Constabulary.
We have also measured the noise exposures of motorcycle patrols for one of the motorist breakdown rescue services. The measurements were carried out during the motorcyclists' normal duties to determine whether their full-day noise exposures were below the limits of the UK Noise at Work Regulations.
References in the open literature:
M.C. Lower, D.W. Hurst, A.R. Claughton and A. Thomas, 1994; Sources and levels of noise under motorcyclists' helmets. Proceedings of the Institute of Acoustics, 16, pt 2, 319-326. ISBN 1 873082 59 2.
M.C. Lower, D.W. Hurst and A. Thomas, 1996; Noise levels and noise reduction under motorcycle helmets. Proceedings of Internoise '96, Book 2, 979 - 982.
**********************************************
Here is a chart signifying what are the max "allowable" values and what are the values we encounter on a day to day basis. Note - when it says motorcycle, that doesn't mean inside the helmet at speed, as it does on the above post.
http://www.headwize.com/articles/hearing_art.htm
90 dbA 8 hrs
92 dbA 6 hrs
95 dbA 4 hrs
97 dbA 3 hrs
100 dbA 2 hrs
102 dbA 1.5 hrs
105 dbA 1 hr
110 dbA 0.5 hr
115 dbA 0.25 hr or less
Note: When the daily noise exposure is composed of two or
more periods of noise exposure of different levels, their combined
effect should be considered, rather than the individual effect of
each. Exposure to impulsive or impact noise should not exceed
140 dB peak sound pressure level.
Figure 2: OSHA Regulation 1910.95 - Occupational noise exposure
As seen in the OSHA Noise Exposure table in figure 2, the louder the sound, the less time it takes for damage to occur. OSHA limits noise exposure levels in the work environment to about 90dB for an 8-hour period, but permits exposure to higher levels for short periods. Many experts believe that the OSHA numbers are too high for hearing safety. EU countries have very strict laws about noise exposure. For example, U.K. employers must take action at two levels of noise exposure: 85dB and 90dB. At 85dB, employers must offer hearing protection and hearing education to employees. At 90dB or higher, employees MUST wear earplugs, and the employer MUST try to reduce the ambient noise level.
60 dB Everyday conversation, ringing telephone.
70 dB Restaurant.
80 dB Heavy city traffic, alarm clock at 2 feet, factory noise, vacuum cleaner, garbage disposal.
90 dB Subway trains, motorcycle, workshop tools, lawn mower.
100 dB Chain saw, pneumatic drill.
110 dB Dance club.
120 dB Rock concert speaker sound, sandblasting, thunderclap.
130 dB Jet take off, gunfire.
Figure 3: Decibel levels of common sounds.
**************************************8
SO WHAT DOES THIS ALL MEAN:
If an ear plug (like the ones I posted above) are rated for 29 dBA then you -7 from that and divide by 2. You get that number, which is about 11dB and you subtract it from the noise level.
SO - if it is 100dB inside the helmet and you subtract 11 dB then you are actually exposed to 89dB.
Since 89 is the UPPER limit of exposure, you might want to consider ALWAYS wearing earplugs.
just in case I ever get cited for earplugs in CA, I'd fight it till the law was changed.
(Love ya honey,,just kidding..kinda 
)
