How High Can the Decibels Go Without Affecting My Hearing?

Many experts agree that continual exposure to more than 85 decibels may become dangerous.

Does the Length of Time I Hear a Noise Have Anything to with the Danger to My Hearing?

It certainly does. The longer you are exposed to a loud noise, the more damaging it may be. Also, the closer you are to the source of intense noise, the more damaging it is.

Every gunshot produces a noise that could damage the ears of anyone in close hearing range. Large bore guns and artillery are the worst because they are the loudest. But even cap guns and firecrackers can damage your hearing if the explosion is close to your ear. Anyone who uses firearms without some form of ear protection risks hearing loss.

Recent studies show an alarming increase in hearing loss in youngsters. Evidence suggests that loud rock music along with increased use of portable radios with earphones may be responsible for this phenomenon.

Can Noise Affect More Than My Hearing?

A ringing in the ears, called tinnitus, commonly occurs after noise exposure, and it often becomes permanent. Some people react to loud noise with anxiety and irritability, an increase in pulse rate and blood processor, or an increase in stomach acid. Very loud noise can reduce efficiency in performing difficult tasks by diverting attention from the job.

Who Should Wear Hearing Protectors?

If you must work in an excessively noisy environment, you should wear protectors. You should also wear them when you are using power tools, noisy yard equipment, or firearms.

What Are the Laws for On-the-Job Exposure?

Habitual exposure to noise above 85 dB will cause a gradual hearing loss in a significant number of individuals, and louder noises will accelerate this damage. For unprotected ears, the allowed exposure time decreases by ONE HALF FOR EACH 5 dB INCREASE in the average noise level. For instance, exposure is limited to 8 hr at 90 dB, 4 hr at 95 dB, and 2 hr at 100 dB. The highest permissible noise exposure for the UNPROTECTED ear is 115 dB for 15 MINUTES/day. Any noise above 140 dB IS NOT PERMITTED.

The Occupational Safety and Health Administration, in its Hearing Conservation Amendment of 1983, requires hearing conservation programs in noisy work places. This includes a yearly hearing test for the approximately five million workers exposed to an average of 85 d5 or snore of noise during an 8-hour work day.

Ideally, noisy machinery and work places should be engineered to be more quiet or the worker's time in the noise should be reduced; however, the cost of these actions is often prohibitive. As an alternative, individual hearing protectors are required when noise averages more than 90 dB during an 8-hour day.

When noise measurements indicate that hearing protectors are needed, the employer must offer at least one type of earplug and one type of earmuff without cost to employees. If the yearly hearing tests reveal hearing loss of l0 dB or more in higher pitches in either ear, the worker must be informed and must wear hearing protectors when noise averages more than 85 dB for an 8-hour day.

Larger losses of hearing and/or the possibility of ear disease should result in referral to an ear, nose and throat physician (otolaryngologist).

What Are Hearing Protectors? How Effective Are They?

Hearing protection devices decrease the intensity of sound that reaches the eardrum. They come in two forms: earplugs and earmuffs.

Earplugs are small inserts that fit into the outer ear canal, To be effective they must totally block the ear canal with an airtight seal. they are available in a variety of shapes and sizes to fit individual ear canals and can be custom made. For people who have trouble keeping them in their ear, they can be fitted to a headband.

Earmuffs fit over the entire outer ear to form an air seal so the entire circumference of the ear canal is blocked, and they are held in place by an adjustable band. Earmuffs will not seal around eyeglasses or long hair, and the adjustable headband tension must he sufficient to hold earmuffs firmly around the ear. Earplugs must be snugly sealed so the entire circumference of the ear canal is blocked. An improperly fitted, dirty or worn-out plug may not seal and can irritate the ear canal.

Properly fitted earplugs or muffs reduce noise 15 to 30 dB. The better earplugs and muffs are approximately equal in sound reduction, although earplugs are better for low frequency noise and earmuffs for high frequency noise. Simultaneous use of earplugs and muffs usually adds 10 to 15 dB more protection than either used alone. Combined use should be considered when noise exceeds 105 dB.

Why Can't I Just Stuff My Ears with Cotton?

Ordinary cotton halls or tissue paper wads stuffed into the ear canals are very poor protectors; they reduce noise only by approximately 7 dB.

What Are the Common Problems of Hearing Protectors?

Studies have shown that one-half of the workers wearing hearing protectors receive one-half or less of the noise reduction potential of their protectors because these devices are not worn continuously while in noise or because they do not fit properly.

A hearing protector that gives an average of 30 dB of noise reduction, if worn continuously during an 8-hour work day, becomes equivalent to only 9 dB of protection if taken off for one hour in the noise. This is because decibels are measured on a logarithmic scale, and there is a 10-fold increase in noise energy for each 10 dB increase.

During the hour with unprotected ears, the worker is exposed to 1,000 times more sound energy than if earplugs or muffs had been worn. In addition, noise exposure is cumulative. So the noise at home or at play must be counted in the total exposure during any one day. A maximum allowable while on-the-job followed by exposure to a noisy lawnmower or loud music will definitely exceed the safe daily limit.

Even if earplugs and/or muffs are worn continuously while in noise, they do little good if there is an incomplete air seal between the hearing protector and the skin. When using hearing protectors, you will hear your own voice as louder and deeper. This is a useful sign that the hearing protectors are properly positioned.

Can I Hear Other People and Machine Problems If I WearHearing Protectors?

Just as sunglasses help vision in very bright light, so do hearing protectors enhance speech understanding in very noisy places. Even in a quiet setting, a normal hearing person wearing hearing protectors should he able to understand a regular conversation. Hearing protectors do slightly reduce the ability of those with damaged hearing or poor comprehension of language to understand normal conversation, However, it is essential that persons with impaired hearing wear earplugs or muffs to prevent further inner ear damage. It has been argued that hearing protectors might reduce a worker's ability to hear the noises that signify an improperly functioning machine. However, most workers readily adjust to the quieter sounds and can still detect such problems.

What If My Hearing Is Already Damaged? How Can I Tell?

Hearing loss usually develops over a period of several years. Since it is painless and gradual, you might not notice it. What you might notice is a ringing or other sound in your ear (called tinnitus), which could he the result of long-term exposure to noise that has damaged the hearing nerve. Or, you may have trouble understanding what people say; they may seem to be mumbling, especially when you are in a noisy place such as in a crowd or at a party. This could be the beginning of high-frequency hearing loss; a hearing test will detect it. If you have any of these symptoms, you may have nothing more serious than impacted wax or an ear infection, which might be simply corrected, However, it might be hearing loss from noise. In any case, take no chances with noise - the hearing loss it causes is permanent. If you suspect a hearing loss, consult a physician with special training in ear care and hearing disorders (called an otolaryngologist or otologist). This doctor can diagnose your hearing problem and recommend the best way to manage it.

©1995. This leaflet is published as a public service; material may be freely used for noncommercial purposes so long as attribution is given to the American Academy of Otolaryngology - Head and Neck Surgery, Inc.,One Prince Street, Alexandria VA 22314-3357

BIKERNET.COM INDEPENDENT MOTORCYCLE NOISE STUDY

In a world of increased levels of constant noise and heightened 
efforts to curb excessive decibel levels motorcycles take a hit. 
Bikernet.com, the world's largest website in the custom motorcycle 
industry, sought to study motorcycle noise against constant 
environmental disturbances and put the motorcycle exhaust sound into 
proper perspective.

Motorcycles are unique in that they are the least pervasive of all 
vehicles jammed onto our roads today. They have the least protection 
and the best mpg ratings of all vehicles. We noted the obvious, 
motorcycles lack bumpers, airbags, double-wall doors or steel 
ceilings, yet take up 1/3 of the space of common sedans, and are more 
agile than trucks or compacts in avoiding dangerous situations. 
Motorcycles have but two defensive measures to enhance their agility; 
visual and auditory awareness. For decades motorists have used the 
excuse that they are unable to see a narrow motorcycle, so it's okay 
to hit one. State legislators are currently dealing with that fallacy.

Yet, still between 70 and 85 percent of all motorcycle/motor vehicle 
accidents are caused by motorists. Plus, the use of cell phones, GPS 
screens, DVDs, CD players and other major distractions are increasing 
the need for motorcycle awareness.

Recent statistics indicate that over 80 percent of motor vehicle 
accidents happened while the driver is distracted by cell phones, 
eating or other interruptions.

Much like emergency vehicles, the sound a motorcycle makes is critical 
to its ability to alert motorists of its whereabouts. That became our 
study criteria and we tested four motorcycles to determine an 
acceptable decibel level to allow a motorcyclist to be heard. We also 
discovered a recent court case that demonstrated this contention. Å 
woman testified she was unaware of the presence of a motorcycle. Sound 
testing proved her a liar. We measured the decibel levels from 2 feet 
away from the open end of the muffler at 45 degrees. We also 
discovered that some states measure decibel levels from as far as 50 
feet away. In that case every motorcycle tested emitted less noise 
than most 18-wheelers.

2003 Harley-Davidson Road King Classic, 1,400cc with mild 
modifications and a full Screamin' Eagle 2-into-1 Exhaust System:
100 decibels at idle
108 decibels at cruising throttle
116 decibels fully revved.

2004 1200 cc Sportster with full aftermarket Samson 2-into-1 Exhaust system:
100 decibles at idle
108 decibels at moderate rpms
120 decibels fully revved.

Custom 1956 Harley-Davidson, 1488 cc, with custom 2-into-2 exhaust 
system with modified shorty mufflers:
102 decibels at idle
111 decibels at cruising speeds
124 decibels revved

2006 Softail Standard 1,400 cc, original from the factory:
97 decibels at idle
102 decibels at cruising speed
111 decibels revved

For reference, we measured the noise levels of cars and trucks passing 
our meter at between 35-45 mph at 10-50 feet distance. Passenger 
vehicles ranged in the 78-83 decibel range whereas trucks ranged from 
90-100 at that distance.

We took each one of these motorcycles and tested them in three traffic 
scenarios.

Passing: Wherein a motorcycle approached a passenger vehicle with 
windows rolled up and radio playing (and without). We tested the 
approach from both sides of the car.

Oncoming Intersection Scenario: Again we used a late model passenger 
vehicle with the windows rolled up a radio playing (and without). This 
time both vehicles approached an intersection and we determined if the 
motorcycle could be heard across an intersection in this test vehicle.

Cross Traffic: Again we tested whether a motorcycle can be heard 
closing on an intersection from a right angle from the oncoming 
vehicle approaching an intersection, when a building exists on the 
right hand corner.

We discovered that the stock motorcycle could not be heard in the 
passing test unless the motorcycle was along side a moving vehicle. If 
a radio was playing at 80 decibels within the vehicle the motorcycle 
would be nearly undetectable. A dangerous situation for a motorcycle 
that takes up limited mirror viewing area.

We discovered that with a radio playing the Sportster could be heard 
at just one car length behind the vehicle. The results were almost the 
same for the Road King.

With the radio off, these motorcycles could be discerned at two car 
lengths. A brief span of time in traffic to maneuver if a car altered 
its direction abruptly.

The custom bike could be easily detected following at 5 car lengths 
and close to 7 if the radio was not in the equation.

The intersection test was the most difficult because speed and 
distance are tricky to determine control. The un-altered 
Harley-Davidson was difficult to hear at all with or without radio 
interference.

The modified Road King and Sportsters had a fleeting chance of being 
heard across an intersection to warn a motorist. The only motorcycle 
that could be easily heard across an intersection was the 1956 Custom 
with modified exhaust.

The final test was most interesting. Again the stock bike would 
virtually arrive at the intersection unheard, whereas the Sportster 
and the Road King were detected for 3 car lengths before the 
intersection. Consequently there would be a moment of driver reaction 
time available, at 35 mph, for the driver or motorcyclist to react to 
a dangerous situation.

Again the custom bike with modified exhaust could be heard from over a 
block away prior to the intersection allowing the driver to be aware 
of an approaching motorcycle and make defensive maneuvers prior to 
entering the intersection.

Our study also identified the consistency of road sound in an 
industrial area in Wilmington, California, which affords almost year 
around riding weather. This street has an average of 450 trucks 
passing in an hour given at 93-100 decibels. An average of 673 cars 
pass daily during a peak hour at a constant 81-83 decibels and maybe a 
dozen motorcycles pass by during that hour for a culminated seconds of 
motorcycle noise at 80-100 decibels.

Our findings point out various considerations regarding motorcycle 
noise regulations. We are not in favor of disturbing or irresponsible 
motorcycle noise. We support Daytona, Florida's anti-revving 
ordinance. Abusive noise use is ticketed. We also support an ordinance 
that allows ticketing for any motorcyclist who abuses his motorcycle 
after 10:00 p.m. at night in a residential district. We believe that 
motorcycles need to make some noise, but that it must be handled 
responsibly.


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