Hear This: Noise Conservation in the Workplace
By Barbara Nessinger, Editor-in-Chief
Some 22 million workers are exposed to potentially damaging noise at work each year, according to OSHA’s most recent estimates. In fact, in 2018, U.S. businesses paid more than $1.5 million in penalties for not protecting workers from noise, with an additional $242 million in workers’ compensation paid out for hearing loss disabilities. And, according to a 2017 study by the National Institute on Deafness & other Communication Disorders, nearly one in four U.S. adults between the ages of 20-69 show signs of hearing loss when tested. [“U.S. adults aged 20 to 69 years show signs of noise-induced hearing loss.” NIDCD, (Feb 2017)]
Workplace noise-related injuries can include temporary or permanent hearing loss and can create physical and psychological stress; reduce productivity; and interfere with communication and concentration. It can also contribute to workplace accidents and injuries by making it difficult to hear warning signals.
Aside from the fact that one cannot put a number on the prospect of a person losing their hearing, it is clear that efforts to protect employees’ hearing are hugely important. Efforts to instill proper noise-reduction PPE practices within the workplace are just as imperative.
UNDERSTANDING OSHA REGULATIONS
OSHA regulates workplace noise by requiring companies to limit the exposure of their workers to high noise levels. In order to ensure that workers are protected in environments with high noise levels (i.e., greater than OSHA-required levels), there are some critical elements to understand.
Noise and hearing conservation is addressed in specific standards for recordkeeping and general industry. To be specific, section 5(a)(1) of the OSH Act, often referred to as the General Duty Clause, requires employers to “furnish to each of his employees’ employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.” (This section also can be used to address hazards for which there are no specific standards, such as noise in agricultural operations.)
Many individual state standards exist, as well. There are 28 OSHA-approved, so-called State Plans that operate state-wide occupational safety and health programs. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA’s, and some might have different or even more stringent requirements.
Occupational noise exposure is addressed specifically by OSHA’s Subpart G–Occupational health and environmental control-1910.95, Occupational noise exposure. Its directives include Enforcement Guidance for Personal Protective Equipment in General Industry; Hearing Conservation Program; and Occupational Noise Exposure; Hearing Conservation.
WHAT TO KNOW ABOUT NOISE CONSERVATION
Deciphering OSHA noise regulations can be a daunting task. OSHA requires an employer to administer a hearing conservation program whenever employees are exposed to noise levels that are at or above an 8-hr, time-weighted average (TWA) of 85 dB (the so-called “Action Level”) or, equivalently, a dose of 50% of the maximum permissible level of 90 dB. This 8-hr TWA is also known as an “exposure action value.” Exposures longer than 15 minutes at 100 dB are not recommended.
Regular exposure of more than one minute at 110 dB risks permanent hearing loss. The minimum requirements of a hearing conservation program include a monitoring program; an audiometric testing program; hearing protection devices; employee training and education; and recordkeeping.
A sound survey is often completed to determine areas of potential high noise exposure. A noise screening is used to determine which areas are higher than 80 dB A. For these areas, an official sound survey will take place. This is normally completed using a sound level meter (SLM). 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. It is believed that engineering controls and administrative controls are ranked as the most effective protection from noise. Engineering controls are measures taken to reduce the intensity of noise at the source, or between the source and a person exposed to the noise, while administrative controls are limitations around noise sources that limit length of noise exposure.
The EU’s requirements on hearing conservation are somewhat more stringent than U.S. regulations. The EU requires a hearing conservation program be implemented when worker exposure levels exceed 80 dBA TWA.
It is sometimes possible to reduce noise levels sufficiently to eliminate OSHA requirements for a hearing conservation program, thus improving productivity, ensuring employee health and resulting in significant savings.
NOISE REDUCTION RATINGS
The 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, in a landmark 1990’s study found that the “labeled manufacturers’ NRRs substantially overestimated the actual field attenuation performance.” [“A controlled investigation of in-field attenuation performance of selected insert, earmuff and canal cap hearing protectors.” Park, MY; Casali, JG (December 1991).] As a result of that study, OSHA recommends that 7 dB be subtracted from the NRR to determine the amount of noise reduction afforded by a hearing protection device.
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 companies and sound-survey companies can help employers ensure their workers’ ears are protected and help keep them in compliance with regulations.
HEARING PROTECTION SOLUTIONS
If engineering controls fail to maintain an 8-hr TWA below 85 dBA, then a hearing protection device (HPD) is mandated by OSHA. There are two general types of HPDs: earplugs and earmuffs. Each one has its own benefits and drawbacks. An industrial expert can usually help with the selection of what type of proper HPD must be worn (OSHA requires that HPDs are free of charge). Another option is to install acoustic panels, if applicable.
There are four general classes of earplugs: pre-molded, formable, custom molded and semi-insert. Pre-molded earplugs don’t 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, but all are able to be shaped by the user prior to insertion. Advantages include the fact that the device forms to the individual user’s ear; something pre-molded earplugs can cannot do. However, they have the disadvantage of requiring the user’s hands be clean before molding/insertion.
Custom-molded ear plugs are cast from each user’s own ear canals. Therefore, they provide a personalized, individualized fit. Semi-inserts usually consist of a soft earplug on the end of band. The band helps maintain the earplug’s position. One key advantage to the band is that the plugs can be quickly inserted and removed.
The obvious difference between earmuffs and earplugs is that earmuffs are not inserted inside the ear canal. Earmuffs instead create a seal around the outside of the ear to prevent noise from reaching the inner ear. They tend to be easy to wear and often provide a more consistent fit than an earplug.
Earmuffs are available that use the principle of active noise control to help reduce noise exposures. It’s important to note, however, that the protection earmuffs offer can be mitigated by a wearer’s large sideburns or glasses; these can cause the seal of the earmuffs to be broken.
The fit of a hearing protector is very important; if the HPD is not worn properly, the NRR is meaningless. There are now fit-testing devices on the market that will verify a proper fit of an HPD. Fit-test systems provide a Personal Attenuation Rating (PAR) that is currently dependent upon the company that manufactures the fit-testing system. Most fit-testing 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.
In addition to devices for noise reduction, many companies produce acoustic panels that can be made for industrial use. Acoustic panels can be an economical and effective means to controlling noise. The panels can increase the intelligibility of speech; mitigate distracting, unpleasant and even intolerable auditory conditions; and can decrease the risk of harm from exposure to excessive noise. Some pre-engineered acoustic panels come in a range of sizes and styles and can be readily positioned within the host room to achieve optimal noise reduction. They can often be customized and finished to fit and/or complement any given architectural layout.
TRAINING AND EDUCATION
The key to preventing noise-induced hearing loss or injury is proper training and education to those exposed to noise. Employees who receive proper training on how to follow a hearing conservation program can reduce their own risks. In addition to making sure workers know the physiological realities of noise exposure, it’s also important to provide information on the importance of annual audiograms and use of appropriate hearing protection.
To support retention of information and also to update and OSHA standards, refresher training can be extremely effective. Even with a “very modest amount of instruction attenuation performance can be significantly improved.” [“Instruction and the improvement of Hearing Protector Performance” Noise and Health Oct-Dec;7(25):41 (Williams, W.,2004).]
A hearing conservation training program can use a variety of materials and media to relay information to employees, including written, video, audio and hands-on experiences. Pre- and post-assessment measurements are also helpful, as are examples of the types of hearing protection available for the employees’ various needs. IHW
- “Preventing Hearing Loss Caused by Chemical (Ototoxicity) and Noise Exposure,” U.S. Dept. of Labor, OSHA Safety & Health Information Bulletins—2018-124 https://www.osha.gov/dts/shib/shib030818.html
ACGIH® is a 501(c)(3) charitable scientific organization that advances occupational and environmental health. Visit the ACGIH website at acgih.org: For information on and to register for upcoming webinars, visit the ACGIH website at acgih.org. To purchase the “Hearing Conservation Program Management” webinar on USB or the “ACGIH TLV for Audible Sound–Understanding the Proposed Notice of Intended Change to the ACGIH TLV for Noise” webinar on USB, visit the ACGIH Online Publications Store (acgih.org/Store) and search for Product ID WB-021-USB and WB-032-USB, respectively.
“U.S. adults aged 20-69 Years Show Signs of Noise-Induced Hearing Loss,” NIDCD, US Dept of Health & Human Services, Feb 7, 2017 https://www.nidcd.nih.gov/news/2017/us-adults-aged-20-69-years-show-signs-noise-induced-hearing-loss
Hearing Health Foundation’s Workplace Hearing Loss statistics/recommendations: https://hearinghealthfoundation.org/hearing-loss-in-the-workplace