The OSHA standard contains a series of program requirements.Engineering Controls: 29 CFR 1910.95(b)(1) requires that "feasible administrative or engineering controls shall be utilized. If such controls fail to reduce sound levels...personal protective equipment shall be provided and used to reduce sound levels..."
Monitoring: 29 CFR 1910.95(d) requires that monitoring be conducted when "any employee's exposure may equal or exceed an 8-hour time-weighted average of 85 decibels.
Testing: 29 CFR 1910.95(g) requires an "audiometric testing program" for "all employees whose exposures equal or exceed an 8-hour time-weighted average of 85 decibels".
Hearing Protectors: 29 CFR 1910.95(i) states that "employers shall make hearing protectors available to all employees exposed to an 8-hour time-weighted average of 85 decibels or greater at no cost to the employees"
Training: 29 CFR 1910.95(k) mandates an annual "training program" for "all employees who are exposed to noise at or above an 8-hour time-weighted average of 85 decibels..." and mandates certain aspects of the training that must be included. This includes the effects of noise on hearing; purpose, advantages, disadvantages, and attenuation of different types of hearing protectors; purpose audiometric testing.
Record Keeping: 29 CFR 1910.95(m) states that employers "shall maintain an accurate record of all employee exposure measurements..."
A sound survey is often completed to determine areas of potential high noise exposure. This type of survey is normally completed using a sound level meter (SLM). There are three types of sound level meters. Type 0 is precision instrument normally used in laboratories. A type 1 is for precision measurements taken in the field. Type 2 sound level meters are less precise than type 1 and are often used to take all-purpose sound level measurements. Noise monitoring is generally completed using a noise dosimeter that integrates "all continuous, intermittent and impulsive sound levels" to determine a person's noise exposure level.
Surveys must be repeated when there are significant changes in machinery and/or processes that would affect the noise level.
Engineering controls and administrative controls are the preferred method to prevent noise exposure. Normally, they do not require personal protective equipment and therefore are normally more protective. However, it is not always feasible to use administrative and engineering controls as the only ways to prevent noise over-exposure. The key is to maintain an 8-hour time-weighted average of less than 85 dBA so that personal protective equipment is not required. On October 19, 2010, the US Department of Labour proposed that the term "feasible" be interpreted as that which is capable of being done, thus enhancing OSHA's ability to enforce this aspect of the standard.
If engineering controls fail to maintain an 8-hour time-weighted average below 85 dBA, then a hearing protection device (HPD) is required. There are two general types of HPDs: earplugs and earmuffs. Each one has its own benefits and drawbacks. The selection of the proper HPD to be worn is commonly done by an industrial hygienist so that the proper amount of noise protection is worn. OSHA requires that HPD be given free of charge.
There are four general classes of earplugs. These include: premolded, formable, custom molded and semi-insert.Premolded earplugs do not require the plug to be formed before it is inserted into the ear. This prevents the plugs from becoming soiled before insertion.
Formable earplugs are made of a variety of substances. However, all each substance shares the common feature of being able to be shaped by the user prior to insertion. One drawback of this is the obvious need for the user to have clean hands while shaping the earplug. They do have the advantage of forming to the users ear, while many premolded earplugs do not accomplish this very well.
Custom molded ear plugs are unique for each person, since they are cast from each user's own ear canals. Therefore, they provide a personalized fit for each individual.
Semi-inserts are generally a soft earplug on the end of band. The band aides in maintaining the earplug in position. They are often useful since they can be quickly removed and inserted.
Earmuffs are another type of HPD. The main difference between earmuffs and earplugs, is that earmuffs are not inserted inside the ear canal. Instead the muffs create a seal around the outside of the ear to prevent noise from reaching the inner ear. Earmuffs are easy to wear and often provide a more consistent fit than an earplug. There are earmuffs available that use the principle of active noise control to help reduce noise exposures. However, the protection earmuffs offer may be mitigated by large sideburns or glasses as the seal of the earmuffs may be broken by these objects.
The United States Environmental Protection Agency (EPA) requires that all hearing protection devices be labeled with their associated noise reduction rating (NRR). The NRR provides the estimated attenuation of the hearing protection device. However, it has been found that the "labeled manufacturers' noise reduction ratings (NRRs) substantially overestimated the actual field attenuation performance." To determine the amount of noise reduction afforded by a hearing protection device, OSHA recommends that 7 db be subtracted from the NRR. The NRR is generally given in a C-weighted format, so to obtain the A-weighted reduction, one must subtract 7 db. OSHA also recommends a 50% safety factor, therefore the final OSHA recommended reduction would be (NRR-7)/2.
Fit Testing for Hearing Protection
The NRR now has some help. Fit testing devices on the market that will verify a proper fit of an HPD (hearing protection device). The fit of a hearing protector is very important, because if the HPD is not worn properly, the NRR becomes irrelevant. Products that will verify proper fit include: 3M EARFit Validation System, FitCheck, FitCheck Solo, INTEGRAfit, SafetyMeter, and VeriPro. Fit-test systems provide a Personal Attenuation Rating (PAR) that is currently dependent upon the company that manufactures the fit-testing system. Most fit test systems provide an A-weighted PAR, which means that the attenuation can be subtracted from the A-weighted noise exposure assessment of the employee or hearing protector user.
Table: Fit-testing systems, PAR measurement method and application to estimate protected exposure level.
Audiometric testing is a very important part of a hearing conservation program. Audiometric testing allows for the identification of those that have lost significant hearing. Additionally, the testing allows for the identification of those who are in process of losing their hearing. Audiometric testing is most important in identifying those who have permanent hearing loss. This is called noise-induced permanent threshold shift (NIPTS).
Proper training and education of those exposed to noise is the key to preventing noise-induced hearing loss. If employees are properly trained on how to follow a hearing conservation program, then the risk of noise-induced hearing loss is reduced. OSHA requires said training to be completed on an annual basis. Proper training is imperative since "even with a very modest amount of instruction attenuation performance can be significantly improved."
OSHA requires that records of exposure measurements and audiometric tests be maintained. Records are also required to have the following:name and job classification
date of the audiogram
employee's most recent noise exposure assessment
background sound pressure levels in audiometric test booths.
Noise exposure measurement records must be maintained for at least 2 years. Audiometric test records must be retained for the duration of the affected employee's employment. Additionally, employees, former employees, representatives designated by the individual employee and the Assistant Secretary all must have access to these records.
Proper program evaluation is important in maintaining the health of hearing conservation program. The National Institute for Occupational Safety and Health (NIOSH) has created a checklist to help evaluate the effectiveness of a hearing conservation program. It can be found on their website. NIOSH recommends that fewer than 5% of exposed employees should have a 15 dB Significant Threshold Shift in the same ear and same frequency.
The National Institute for Occupational Safety and Health is pushing a higher emphasis on a hearing loss prevention program rather than a hearing conservation program. While this change may seem superfluous, it is important to note the advancement. Prevention implies a response by the workplace caused by initial signs of employee hearing loss rather than instilling a new set of policies (such as "buy quiet") and thinking (such as hearing protection training and education) to decrease the possibility of occupational hearing loss from happening in the first place.
The Buy Quiet policy is an easy way to progress towards a safer work environment. Many traditionally noisy tools and machines are now being redesigned in order to manufacture quieter running equipment, so a "buy quiet" purchase policy should not require new engineering solutions in most cases. As a part of the "buy quiet" campaign, the New York City Department of Environmental Protection released a products and vendor guidance sheet in order to assist contractors for achieving compliance with the New York City Noise Regulations.
In order to make these plans effective, employees and administration need to be educated in occupational noise-induced hearing loss prevention. It is also necessary to identify and examine sources of noise first before being able to control the damage it may cause to hearing. For example, the National Institute for Occupational Safety and Health has conducted a study and created a database on handheld power tools for the sound power levels they expose their operators to. This Power Tools Database allows contractors in a trade-skill profession to monitor their exposure limits and allow them preparation to prevent permanent hearing damage.
Due to increased worry among both parents and experts regarding Noise-induced hearing loss (NIHL) in children, it has been suggested that hearing conservation programs be implemented in schools as part of their studies regarding health and wellness. The necessity for these programs is supported by the following reasons: 1. Children are not sheltered from loud noises in their daily lives, and 2. Promoting healthy behaviors at a young age is critical to future application. The creation of a hearing conservation program for children will strongly differ from those created for the occupational settings discussed above. While children may not be exposed to factory of industrial noise on a daily basis, they may be exposed to noise sources such as firearms, music, power tools, sports, and noisy toys. All of these encounters with noise cumulatively increases their risk for developing Noise-induced hearing loss. With NIHL being a fully preventable ailment, providing children with this type of education has the potential to reduce future incidence of this condition. There are multiple organizations in existence that provide educators with the appropriate material to teach this topic; teachers simply need to be proactive about accessing them. Below are examples of hearing conservation programs that have been designed specifically for children.
This is the primary goal of most hearing conservation programs at the elementary, middle, and high school levels is to spread knowledge about hearing loss and noise exposure. When an educational program is being created or adapted for use with children, behavior change theories are often employed to increase effectiveness. Behavior theory identifies possible obstacles to change while also highlighting factors that may encourage students to change. The following are elements that are also considered during the implementation of a new program for children:
1. Adaptation of the program for the specific population (age, demographic, etc.)
2. Use of interactive games, lessons, and role-playing
3. Time to apply the skills that are taught
4. Reoccurring lessons on the same topic area
Dangerous Decibels is a program designed to teach concepts related to the prevention of noise-induced hearing loss. Proven to be effective for children in 4th through 7th grade, children are engaged in hands-on activities during this 50-minute presentation. The class will learn about what sound is, how their ears hear and detect it, and how they can protect their hearing from dangerous decibels. Throughout the program, the class focuses on three strategies: Turn it Down, Walk Away, and Protect your Ears.
Created by the American Speech-Language-Hearing Association, this campaign aims to teach children and their parents about practicing safe listening routines when listening to music through personal devices, such as an iPod. With the help of sponsors, ASHA hosts an educational concert series to promote safe music listening.
Run by the Ear Science Institute of Australia, this school program was created to educate elementary-age children on the risks of high listening levels and the effects of hearing loss. Program has a mascot named Charlie and utilizes sound level meters, computer games, apps, and take-home packets to teach the concepts. Teachers also receive addition activities and worksheets for continued learning opportunities.
Organized by the United States National Institutes of Health, this is a campaign created with the aim to increase parental awareness of both the causes and effects of noise induced hearing loss. By targeting parents instead of children, the goal is for adults to influence the behaviors of their children before bad habits are even created. Resources provided include web-based games and puzzles, downloadable graphics, and tips for school and home environments.
Created by The Hearing Foundation of Canada, the Sound Sense classroom program teaches children how hearing works, how it can stop working, and offers ideas for safe listening. The classroom presentation satisfies the requirements for the science unit on sound taught in either grade 3 or 4, as well as the healthy living curriculum in grades 5 and 6. In addition, the webpage provides resources & games for children, parents, and teachers.
Just as program evaluation is necessary in workplace settings, it is also an important component of educational hearing conservation programs to determine if any changes need to be made. This evaluation may consist of two main parts: assessment of students' knowledge and assessment of their skills and behaviors. To examine the level of knowledge acquired by the students, a questionnaire is often given with the expectation of an 85% competency level among students. If proficiency is too low, changes should be implemented. If the knowledge level is adequate, assessing behaviors is then necessary to see if the children are using their newfound knowledge. This evaluation can be done through classroom observation of both the students and teachers in noisy classroom environments such as music, gym, technology, etc.
The Mine Safety and Health Administration (MSHA) requires that all feasible engineering and administrative controls be employed to reduce miners' exposure levels to 90 dBA TWA. Miners may not be exposed to sounds exceeding 115 dBA with or without hearing protection devices (30 CFR Part 62).
The Federal Railroad Administration (FRA) encourages, but does not require, railroads to use administrative controls that reduce noise exposure duration when the worker exceeds 90 dBA TWA (73 FR 79702).
The U.S. Department of Defense (DOD) specifies that engineering controls be employed to reduce the noise levels at the source. The goal of these controls is to reduce ambient steady-state noise levels to 85 dBA regardless of TWA exposure and to reduce impulse noise levels to below 140 dB pSPL (Instruction 6055.12).
The European Union (EU) requires a hearing conservation program be implemented when the worker exposure levels exceed 80 dBA TWA. Note that this is stricter than hearing conservation regulations in the United States. The directive specifies a variety of noise reduction methods, including administrative controls to reduce worker exposure duration, the provision of quieter equipment, and adequate maintenance of machinery and other noise sources (European Parliament and Council Directive 2003|10|EC).