1Module 2 - Noise Audit Training Purpose of this moduleThis module provides training on noise required to conduct a noise audit. It covers the following topics:Noise & hearing loss preventionHearing protectorsFitting of hearing protectorsWashington state noise regulationsModule 3 also provides required training and covers how to take basic noise measurements and hearing loss recordkeeping.
2Module 2 - Noise Audit Training To do noise audits you must have training in the following:Noise and hearing loss preventionHearing protectorsFitting of hearing protectorsWashington state noise regulationsConducting basic noise measurementsHearing loss prevention recordkeepingThis module covers items 1–4. Module 3 covers items 5 & 6.
3Photo by Jim Cullenaus in Creative Commons DefinitionsSound LevelLoudnessMeasurements made by a sound level meterTechnically: the intensity of sound pressure waves hitting the ear drumPhoto by Jim Cullenaus in Creative Commons“Sound levels are measured in decibels. More about that in the next few slides.”
4Definitions Noise Often described as “unwanted sound” Sound that is too loud, disturbs sleep, interferes with conversation, or causes hearing loss.Community or environmental noise is regulated by local ordinances.Workplace noise exposure is regulated by L & I - DOSH.Photo by K. Pusztavari in Creative Commons
5Definitions Noise Exposure 1 Hour?8 Hours?Sound level and duration – how loud and how long a person is exposed to noise.What a person actually experiences at the ear – not just what noise a loud machine makes.“Sound levels drop off fairly quickly as you move away from a noisy machine – unless it is in a confined area where the loud noise will reflect off walls back to your ears.”
6Definitions Decibel (dB) The standard measurement of sound level A logarithmic scale – 95 decibels is ten times the intensity (or energy) of 85 decibels“The healthy human ear is able to hear sound over a huge range of loudness and frequency (pitch). Instruments can measure the amount of energy of sound and the unit of measurement used is the decibel. 95 decibels will do about 10 times the damage to the ear as 85 decibels. To most of us however, 95 decibels will sound about twice as loud as 85 decibels.”85 dB95 dB
7Definitions Another View of Decibels & Loudness One machines generates a noise level of 100 decibels.Two identical machines in the same room, will generate a noise level of 103 decibels.100 decibels“ To most of us, the two machines will sound only a little louder than the one machine. However the damage to the ears over time will be greater.”103 decibels
8Time Weighted Average (TWA) DefinitionsTime Weighted Average (TWA)TWA – average noise exposure a worker receives.TWA8 – Noise exposure over an hour day.The DOSH noise standard is based on an 8-hour average noise exposure.Highly variable noise levels are common in construction.“Noise in construction can include short exposures to very high noise, followed by long periods of relative quiet. But the average exposure can still exceed the DOSH noise exposure limits. (more about that in the next slides)”
9Average Noise Levels How noise exposure can vary over time 95 dB85 dBThis graph shows how a construction worker might be exposed to noise on a typical day. In the morning, he may use a loud grinder off and on several times, do something quiet just before lunch, then run a backhoe in the afternoon until quitting time. His average noise level for the day would be about 90 decibels.80 dB8 AMNoon5 PMA typical construction worker’s day of noise exposure
10The Outer Ear The visible ear and ear canal The shape of the ear canal can affect how well earplugs fit.
11The Middle EarThe middle ear includes the eardrum and these three tiny bones that transmit sound to the inner ear“ Sound vibrates the eardrum, which in turn vibrates the tiny bones which is converted to nerve impulses in the inner ear. The middle ear is where children and some adults can get infections (fluid in the ear) which can affect hearing.”eardrum
12The Inner Ear The inner ear includes the cochlea and nerves “The inner ear is able to detect and withstand a huge range of sound intensity, but it does have its limits.”Damage from noise exposure occurs in the inner ear
13The Inner Ear - CochleaThe cochlea contains tiny hair cells which are moved by sound waves.Loud noise knocks these hair cells over.Eventually they never recover, resulting in hearing loss.Inside the cochlea“The cochlea is filled with fluid that transmit sound energy to the hair cells. The hair cells that detect high frequency noise are usually damaged first, since they are at front of the cochlea.”Hair cells
14The Hair Cells in the Cochlea Normal hair cellsNoise damaged hair cells“ The tiny hair cells in this part of the ear are flatten out when exposed to high noise levels. If the exposure is short, the hair cells raise back up. If the exposure is long or extremely loud, the hair cells don’t recover and hearing ability is reduced. When all the hair cells are damaged, complete deafness occurs.”
15Long Term Exposure to Noise Our ears can recover from short exposure to loud noise, but over time nerve damage will occur.The louder the noise and the longer the exposure, the greater chance permanent damage will occur.There is really no such thing as “tough ears” or “getting used to it”.“People who say they are “used to the noise” have probably already lost some of their hearing.”
16Hearing Loss From Noise Exposure Hearing loss from noise exposure is often not noticed at first because it is so gradual.Usually a person loses the ability to hear higher pitches first.Often the first noticeable effect is difficulty in hearing speech.Photo by Mike Krzeszak in Creative Commons“Speech includes higher pitches such as in the letter “s”. People who have some hearing loss will often say “I can hear you talking, but I can’t understand you”. The difficulty in hearing speech is usually worse in a crowded room when many people are talking.”Other signs that a person is losing their hearing is that they will often turn up a TV or radio, or they may say they can’t hear birds singing or the voices of small children. Hearing aids only partially help people with severe hearing loss.
17Tinnitus From Noise Exposure Exposure to high noise levels can also cause permanent ringing in the ear or “tinnitus”.Tinnitus sufferers usually complain of constant whistling, squealing, roaring or buzzing in one or both ears.Severe tinnitus can disrupt sleep, reduce concentration and cause irritability and depression.“Tinnitus is difficult to treat. Many doctors will tell a person with tinnitus that “they just have to live with it” . There are several treatments that can provide some relief however, including certain drugs, masking devices worn in the ears, or other devices which help the brain ignore the sound.” [For more information on treatment on tinnitus contact the American Tinnitus Association in Portland, Oregon. Their phone number is or ]
18What is Too Much Noise Exposure? Damage from noise exposure depends on the loudness and length of exposure.Scientific studies have shown that hearing loss will occur when 8-hour average noise exposure exceeds 85 decibels.Photo by Ricard York in Creative Commons“The greater the noise level, the more quickly hearing loss will occur. Short exposure to loud noise can cause a temporary hearing loss. Normal hearing will return if no further exposure occurs. But years of exposure to very loud noise, even if the time of exposure is short each day, will gradually cause hearing loss. Most people can tolerate exposure to noise levels under 85 decibels for years without any noticeable hearing loss, but some people will have hearing loss when exposed to average noise levels as low as 80 decibels.”
19What is Too Much Noise Exposure? The risk of hearing loss increases dramatically as noise levels increase.Exposure to noise levels above decibels for even 5 minutes is very risky.Impact or banging noise above decibels will cause immediate damage to nerves in the ear.“Chain saws can be as loud as 110 decibels running at full power. Gunshots and jet engine noise are typically at 140 decibels or above depending on how close you are.”Photo by Tuomas Karppinen in Creative Commons
20Examples of Commonly Used Noisy Equipment Noise LevelsExamples of Commonly Used Noisy EquipmentEquipment Noise Level Back Hoe decibels Chain Saw 110 decibels Front-end Loader decibels Gunshot 140 decibels Jackhammer 112 decibels Lawn Mower 90 decibels Tractor decibels Circular Saw decibels“These noise levels are approximate.”
21Types of Hearing Protection There are three types of hearing protection – ear muffs, earplugs and ear caps.Ear muffs and earplugs provide about equal protection, ear caps somewhat less.earmuffs“The noise regulations require that employees can select hearing protection from at least two different types.”earplugsear caps
22Types of Hearing Protectors All hearing protectors are designed to reduce the intensity (loudness) of noise to the inner ear. All three types have advantages and disadvantages and people vary on which they prefer to use. Wads of cotton or cloth are not acceptable as hearing protectors.“We will cover the various types of hearing protection in the next several slides.“Cotton doesn’t work!!
23Hearing Protection – Ear Plugs Earplugs are made of foam, rubber or plastic and are either one-size-fits-all or in sizes small, medium and large. Some are disposable, some are reusable. They are lightweight, and require no maintenance. They are inserted into the ear canal.“Foam earplugs are disposable and are usually discarded after a day’s use or more frequently in dirty environments. Some plugs are connected by a cord to prevent dropping or losing them.”“ Re-usable plugs should be cleaned periodically in warm soap and water. Earplugs should not be handled with dirty hands. Some earplugs have little “handles” for use in dirty environments.”
24Ear Plug ComfortSome people may find ear plugs uncomfortable to wear for long periods at first.Ear plugs rarely cause infection or prolonged irritation of the ear canal.Most people can find a comfortable fit by trying several different sizes, types or brands.Custom-molded earplugs can be obtained for maximum comfort.“ Ear plugs must be kept clean to minimize irritation. Sometimes they can push wax against the eardrum making it necessary for frequent wax removal. It can take a little time to get used to wearing earplugs. Custom-molded earplugs can be provided for people who find it difficult to use any other earplug. They must be replaced every year or so.”Custom-molded earplugs
25Getting a Good Fit With Earplugs The shape of the outer ear and the ear canal can affect insertion of earplugs.People have different size ear canals.The shape of the “tragus” on the ear can sometimes interfere with earplug insertion.“ This is why we have several types of hearing protection available for our employees.”
26Inserting Foam Earplugs Foam type earplugs must be inserted properly into the ear for complete protection.“The technique for inserting earplugs is to pull the ear up and back, roll the earplug into a small cylinder, push it into the ear canal and hold there for a few seconds until it expands and fills the ear canal. This will provide the tightest fit and greatest protection.”Roll earplug into small cylinder first, then insert in ear.
27Inserting Foam Earplugs “The left picture shows plugs only partially inserted into the ear canal – a common mistake. The springiness and shape of some foam earplugs can affect the fit. If one brand doesn’t work, a different brand or shape may fit better.”Earplug incorrectly insertedEarplug correctly inserted
28Pre-formed (Rubber) Earplugs Preformed earplugs come in several sizes.Proper seating in the ear is essential.Comfort is important – an uncomfortable plug will not be worn consistently.“ Preformed earplugs come in different sizes because people have different ear canal size and shape. The plug should be snug in the ear, but comfortable. A simple test to determine if the plug fits properly is to put your hands over your ears and see if there is a difference in the loudness. If there is a difference, the plug is not fitting properly.”
29Ear MuffsEar muffs cover the whole ear and are preferred by some people.They have replaceable pads and some high-tech styles filter out specific noise pitches.They last longer than most plugs.“The red muff shows the replaceable pads. These pads can become flattened, cracked or break down over time resulting in a poor seal on the head and noise leakage into the ear.”“Ear muffs are slightly better at reducing low-frequency (roaring or rumbling) noise.”
30Attached Earmuffs Some muffs are attached to hardhats or goggles. Some high-tech muffs can filter out certain frequencies or have radios inside for communication in high noise areas.“ Most earmuffs attached to hardhats are somewhat less protective than stand alone earmuffs. For really loud noise levels, earplugs can be worn under earmuffs.”
31Ear Muff Comfort & Glasses Muffs can be uncomfortable in hot weather.Muffs don’t seal well for someone with glasses or heavy sideburns.Position of the head band will also affect how well the muff is sealed.“ Some people find muffs uncomfortable from the pressure on the head from the band. The band is adjustable and different brands have different band tightness. Users should be given the opportunity to try on different brands and adjust the band for the most comfortable fit. Muffs that don’t seal well can leak noise into the ear. The young man in the photo will have noise leaks under the earmuffs because of his glasses and improper placement on his head.”
32Ear Muff Band PositionSome earmuffs are made with bands that can fit behind the neck or under the chin.The highest protection is on top of the head.Check directions to ensure muffs are adjustable for other positions.“ Some people prefer wearing the band at the back of the neck, or need to do so if they are wearing a hardhat or other cap. Some muffs can be adjusted for any position, others can only be worn with the band on top if the head and will not fit properly in any other position. The NRR rating for behind the neck or under the chin is 2 or 3 decibels less than the top of the head position.”
33Ear CapsEar caps are like earplugs, except they do not go into the ear canal, they only block it.They are good for occasional use or for people who find earplugs uncomfortable.They are not as protective as earplugs or muffs.“Earcaps only reduce noise to the ear by about 10 decibels at best. Depending on the fit, some will be even less protective. They would not be acceptable for constant noise exposure above 95 decibels. Like regular earplugs they should be snug, but not too tight, and the cap itself must be properly seated in the ear canal. ”
34Hearing Protection Attenuation Definition: How effectively noise protectors reduce noise to the ear[click again to show ear plug moving into ear canal.] The ear plug shown moving into the ear canal here will have a specific attenuation depending on the manufacturer when it is properly inserted as shown in previous slides.” [Note: this rough depiction does not show proper insertion.]It is the difference between noise out here,and the noise in here.
35Noise Reduction of Hearing Protection The “noise reduction rating” or “NRR” of hearing protection is measured in decibels.The NRR is found on the earmuff or earplug package. The higher the number, the greater the protection (attenuation).The actual effective protection is seven decibels less than rating on package.“The NRR rating is established by EPA in a laboratory setting where noise measurements are different than those taken in the workplace (C-weighting instead of A-weighting). Therefore, the A-weighted noise reduction is 7 decibels less the printed NRR as required in Table 2 of the Noise Rule. The A-weighted noise more accurately represents how the human ear responds to sound levels. Many experts say that because of improper fit and use, actual protection can be half the NRR rating on the package.”
36Combined Use of Earplugs and Muffs Dual hearing protection can be worn in extremely high noise areas (above 105 decibels).Wearing earplugs under earmuffs will provide effective protection two decibels less than the higher NRR rating of the two protectors.“Table 2 in the Noise Rule explains dual hearing protection in more detail. The point to remember is that you don’t subtract seven decibels from the NRR rating with dual hearing protection, but only subtract two decibels from the higher NRR rating of the two protectors.”For more information, see Table 2 in the Noise rule
37Very Loud Noise & NRRHearing protectors must have an NRR rating of at least 20 decibels for noise exposure above 115 decibels.Exposure to impact or banging noise above 140 decibels also requires using hearing protectors with an NRR of 20 decibels or greater.Piledriver – impact noise level can be as high as 195 decibels at 30 feet.“Most foam ear plugs and well-made ear muffs will have an NRR rating greater than 20 decibels. However, many ear caps do not, which is why knowing the NRR of a particular brand of earplug, ear cap or ear muff is so important.”Photo by ZeroOne in Creative Commons
38How can you hear anything with earmuffs on? Using earmuffs or plugs in noisy areas can actually make it easier to hear coworkers or machinery. They are similar to dark glasses that reduce the sun’s glare making it easier to see. Overprotection should be avoided.“Loud background noise can overwhelm the ears making it difficult to hear a coworker. When used correctly earplugs or muffs mute the background noise so that a coworker or warning bell is actually easier to hear. However, It is possible to overprotect with an earmuff or earplug that has an NRR higher than necessary. More is not always better. Select hearing protection that will reduce the noise to ear to just below 80 decibels. People who have some hearing loss will have more difficulty hearing while wearing plugs or muffs. Special earplugs or muffs are available that make it easier for these individuals to hear while wearing hearing protection. Hearing protection vendors may carry or be able to obtain these special plugs or muffs with filters. We obviously want to avoid the tragedy of a worker being back over by a dump truck as shown in the lower photo because he couldn’t hear the back-up alarm.”
39Proper Use of Hearing Protection Earmuffs and plugs provide good protection only when used properly.Sometimes people will remove hearing protection for “just a minute” in a noisy area.In areas of very high noise exposure, this can quickly result in noise overexposure.“Some workers will remove their plugs or muffs because they are uncomfortable, which is why this is an important question to ask workers who must wear them.”
40Proper Use of Hearing Protection It takes just a few minutes of unprotected exposure at noise above 115 decibels to risk hearing damage.Earplugs not well inserted into the ear canal will not provide complete protection.Likewise, earmuffs not snug and covering the ear completely will “leak” noise into the ear.“The Noise Rule requires that a warning sign like this one is posted at the entrance or perimeter of an area where the noise level is above 115 decibels. Many employers post these or similar signs when the noise level is above 85 decibels.”
41Hearing Aids Are Not Hearing Protection Hearing aids do not block out enough sound for most workplace noise. Some hearing aids can actually increase the noise level at the ear. Just turning off the hearing aids will not prevent further hearing loss from noise exposure.“Some people with hearing loss think that if they just turn off their hearing aid they will not suffer any more hearing loss since they are already deaf. More noise exposure will only make their hearing loss worse. Some of the newer digital hearing aids have detectors that can instantly turn off or turn down in high noise areas. Users of these devices should check with their audiologist or hearing aid vendor if they are going to be worn in high noise areas.”
42Portable Radios/CD Players/I-Pods Standard portable radios, CD players or I-Pods do not provide protection from noise.The earphones are not earmuffs and the music only adds to other background noise.These devices can exceed 85 decibels by themselves.Photo by Cato Bravo in Creative Commons“Some people have the mistaken idea that these devices can act as hearing protection, since they do drown out quieter background sounds. But they don’t drown out louder background noise. Some of the newer headphones and earbuds made in recent years do provide noise protection, but our company policy on their use is [state your policy]”
43Hearing Loss Prevention(Noise) Rule DOSH adopted a revised rule on Hearing Loss Prevention/Noise in 2003.This revised rule had no new requirements, but included noise audits as an option to audiometric testing.To view rule, click here“The noise rule has been in effect since 1973 with a number of revisions since then.”
44Hearing Loss Prevention/Noise Rule The Rule has six main requirements:Conduct employee noise monitoring,2. Install feasible noise reduction controls when employees are exposed to 8-hour average noise over 90 decibels,3. Make sure employees wear hearing protection when exposed to 8-hour average noise levels of 85 decibels or greater,“These requirements apply to all employers and businesses who have employees exposed to loud noise.”
45Hearing Loss Prevention/Noise Rule The Rule has six main requirements (continued):4. Train employees on effects of noise and use of hearing protection,5. Periodically check employee’s hearing with audiometric testing (or use the noise audit option),6. Post warning signs at high noise areas.“Warning signs are required when noise levels are above 115 decibels.”
46Noise Rule Requirements Noise MonitoringThe Noise Rule applies to any employer who has employees exposed to average noise levels of 85 decibels or above.If workers need to shout to be heard three feet from each other, the noise level is probably above 85 decibels.Noise levels must be measured with noise instruments.85 decibels“ We will keep records of noise level measurements for as long as you are employed with us and we rely on noise audits results.”
47Noise Rule Requirements Reduce Noise Levels Where FeasibleIf employees are exposed to average noise levels above 90 decibels, you must reduce noise levels with controls such as enclosures, barriers, or mufflers.Controls are possible for many noise sources.The DOSH Noise Reduction Ideas Bank has examples of controls.90 decibels[Noise controls your company has installed can be discussed here.]Click here to go to Noise Reduction Ideas BankEnclosed and muffled generator
48Noise Rule Requirements Provide Hearing Protection for EmployeesWhen controls are not possible, provide hearing protection for employees.Employees can select a hearing protector from at least two choices.Hearing protectors must be appropriate for conditions.Make sure employees wear hearing protectors whenever they are exposed to excessive noise.[You can show the different types of hearing protection you provide your employees here.]
49Noise Rule Requirements Hearing Protection RequirementsThe table below shows noise levels and when hearing protection must be worn.Noise Level Employee Exposure Time85 decibels 8 hours or more90 decibels 4 hours or more100 decibels 1 hour or more105 decibels 30 minutes or more110 decibels 15 minutes or more115 decibels Hearing protection always required“These limits are found in the DOSH regulations on noise and are based on scientific studies of the effects of loud noise on people. You can still work in areas with these noise levels as long as you have proper hearing protection – ear muffs or ear plugs.”
50Noise Rule Requirements Audiometric Testing (Hearing tests)Provide hearing tests to employees who are exposed to average noise levels above 85 decibels.Provide the hearing tests within six months of first employment or first exposure to noise.Provide hearing test records to affected employees.Audiometric testing booth“We have made the decision to conduct noise audits in lieu of audiometric testing as allowed in the Noise Rule.”Noise audits are an option to audiometric testing for short-term employees.Audiogram
51Noise Rule Requirements Worker TrainingTrain exposed workers when they are first assigned to a noisy job or position.Train on the following topics:Effects of noiseNoise controls used in your workplacepurpose of hearing protectioninstructions on hearing protection usePurpose & procedures of audiometric testingTo view a worker training module on these topics, click here
52Noise Rule Requirements Noise Warning SignsPost warning signs at the entrance or edge of areas or rooms where noise levels exceed 115 decibels.
53Check Your Understanding Question 1Hearing loss will occur when:The noise levels hurt the earsThe noise level is above 85 decibelsThe noise level is above 85 decibels over 8 hours.c) is the correct answer. However, noise levels that hurt the ears will likely cause hearing loss too.
54Check Your Understanding Question 2Exposure to noise for a short time can cause hearing loss when:When the noise level is above 115 decibels.When the noise is right next to the ear.Short exposures will not cause hearing loss.d) A person is very sensitive to noise.a) Is the best answer.
55Check Your Understanding Question 3What is the best hearing protection?Ear plugsb) Ear muffsc) Either earplugs or earmuffsd) The one that the employee prefersd) is the best answer, providing the employee is trained and wears them properly. An employee will not likely wear hearing protection that is uncomfortable. c) is also correct
56Check Your Understanding Question 4What is NRR?The noise level of rifles.The noise rating of loud machines.The noise reduction rating of hearing protection.A measure of how well earplugs work.c) Is the correct answer. d) is also partially correct, although not just for earplugs.
57Check Your Understanding Question 5The WISHA noise rule requires the following:Provide hearing protection for all employeesb) Find ways to reduce noise levels first.c) Wear earplugs when the noise level is above 85 decibels.d) Provide hearing protection in noisy areasb) Is the best answer. c) is partially correct, if noise controls are not feasible.