How to Develop an Effective Hearing Conservation Program
An Easy Guide
June 17, 2019
Our sense of hearing plays an essential role in how we communicate and experience the world, how we stay aware of our surroundings and thus, safe. That’s why, when hearing loss becomes an all-too-common reality, taking its irreversible toll on individuals, businesses and society, organizations need to step in and take preventative action.
A Hearing Conservation Program places hearing loss prevention at its core. This typically includes these six initiatives:
1. Noise exposure assessment
2. Audiometric testing
3. Hearing protection selection and fit testing
4. Employee training and education
5. Record keeping
6. Program evaluation.
In this guide, we will go over the fundamentals required to start a Hearing Conservation Program for your organization. To name a few, we will discuss:
- What is NIHL?
- How to monitor noise exposure
- Types of hearing protection devices
- Earplug fit testing
- How to motivate employees to wear HPDs
But first, what causes hearing loss?
Over 5% of the world’s population – around 466 million people - suffer from disabling hearing loss, according to the World Health Organization (WHO).
Hearing loss – ranging from a mild difficulty in hearing conversational speech to profound deafness - is influenced by factors like genetics, certain diseases and medicines, and ageing, but also by a factor well within our control – excessive exposure to loud noise.
What is NIHL and how do you recognize it?
Noise-induced hearing loss (NIHL) is the most common preventable occupational injury, according to WHO. In a working environment, noise or unwanted sound at hazardous levels, is usually the by-product of industrial processes.
1. Is permanent and progressive
2. It’s usually bilateral (affects both ears)
3. Usually causes no pain
4. Leaves no visible trauma
5. Is often unnoticeable in its early stages and may take years to diagnose
6. Accumulates with each over-exposure
Its global economic impact for businesses is estimated at US$ 750 billion. But the localized and personal cost of NIHL translates to physical and psychological stress, hence, reduced worker productivity and efficiency.
Hearing loss in the workplace also increases the risk of accidental injuries. According to one study., respondents with hearing troubles were twice as likely to experience an accidental injury than those with good hearing.
NIHL occurs across a wide spectrum of industries, but workers in some industries are more exposed to dangerous levels of noise. These industries are agriculture, mining, construction, manufacturing, utilities, transportation and the military.
Studies show construction workers have significantly increased risk of hearing loss compared to others, with increasing risk by work duration.
Signs that noise may be a problem in your workplace
1. Employees hear ringing or humming after exposure to loud sounds.
2. Noise is impeding communication, so that employees must shout to be heard by a coworker an arm’s length away.
3. Employees experience temporary loss of hearing after leaving work.
If you observe any of the symptoms above, it’s time to measure environmental noise.
Hearing loss prevention starts with monitoring exposure to noise.
According to OSHA standards, a hearing conservation program is required “whenever employee noise exposures equal or exceed an 8-hour time-weighted average sound level (TWA) of 85 decibels measured on the A scale (slow response) or, equivalently, a dose of fifty percent.
So, employers are required to monitor all employees whose noise exposure exceeds 85dB in 8 hours. This includes all continuous, intermittent and impulsive noise between 80 and 130dB.
There are two commonly used methods of monitoring noise levels:
1. Area sampling using a sound level meter
2. Personal sampling with a noise dosimeter, also called a personal sound exposure monitor.
The sound level meter reads the instantaneous or continuous noise level in a specific area over a specific period, and is accurate only when noise levels are constant in the area.
For mobile workers, the personal noise dosimeter gives a more accurate measure of the unprotected exposure. Using this method, the dosimeter microphone is clipped on the shoulder near the ear. The dosimeter remains on the worker for a certain sampling period – several hours, or even the entire workday – and continuously monitors the incoming noise. At the end of the sampling period, a readout shows the average equivalent noise level for that entire sampling period.
Both methods measure the unprotected exposure; an estimate of the protected exposure must be made using the noise attenuation rating of the hearing protector. Since there’s no way to tell how much protection an individual worker is receiving from their hearing protector, such an estimate is merely a guess.
The best method is to directly measure the individual’s protected exposure with in-ear exposure monitoring.
In-ear exposure monitoring measures and records the worker's actual protected noise exposure, over their entire work shift. This technology provides real-time monitoring throughout the workday, and alerts the worker when noise dose approaches or exceeds safe limits.
Assessment of hearing loss also requires a review of audiograms, hearing protection data and clinical history of a worker.
Performed by certified CAOHC-certified hearing conservationists, industrial hygienists and audiologists, audiograms are a common way to evaluate workers’ hearing sensitivity over time. These tests, performed within the first 6 months of an employee’s first exposure to noise (baseline audiograms), and annually thereafter, constitute a record of worker’s hearing thresholds over time at various frequencies.
A threshold between 0 and 25dBHL is considered the normal range for an adult.
· mild hearing loss happens at 25 to 40dBHL
· moderate hearing loss at 40 -55 dBHL
· moderate to severe at 55-70 dBHL
· severe hearing loss at 70-90 dBHL
· profound hearing loss - 90dBHL or higher
According to regulations, audiograms and audiogram results must be made available to all employees and at no cost. They also need to be stored for the duration of employment and a program follow-up should mention if a referral is required for further testing.
For more insight on hearing protection terminology, check out the Howard Leight glossary.
Hearing conservation practices require a clear picture of HPD effectiveness. Earplug fit testing provides a real-world metric to determine if employees are receiving optimal protection for their noise environment, require additional training or need a different model of HPD.
Earplug testing benefits safety managers, as well as employees. For managers, it fulfills regulatory requirements for training and documentation. For employees, it showcases the importance of proper protection in the workplace, helps them select and compare protectors to find the best choice for their ears and specific applications, and provides feedback on what a proper fit looks and feels like.
Other benefits of fit-testing:
- Workers can try different earplugs to find the best combination of fit, comfort, and attenuation
- Overprotection can be measured and identified
- Wearers give immediate feedback
- Perpetuates peer training as trained workers share their knowledge
A Honeywell Howard Leight study revealed that when inviting workers to try a second pair of earplugs, major leaps in attenuation were identified. Field testing of hearing protectors bridges the gap between the laboratory estimates of attenuation and the real-world attenuation achieved by workers as they normally wear the protectors.
The American National Standards Institute (ANSI) promulgates consensus standards used to inform regulations. In the OSHA Hearing Conservation Amendment, ANSI standards are cited for calibrating audiometers used in annual testing, and for sound level meters used in noise monitoring.
OSHA issues specific regulations for recordkeeping and general industry, including methods for estimating the adequacy of hearing protector attenuation and acoustic calibration of audiometers.
When noise exposures exceed mandated levels, engineering and administrative controls are the first line of defense. Engineering controls reduce sound exposure by modifying or replacing equipment or making physical changes at the noise source or the transmission path. Inexpensive engineering controls include choosing low-noise machinery, lubricating equipment, or adding sound walls to isolate the employee and the noise.
Administrative controls include such actions as giving noise-exposed employees break time in quiet areas, or rotating employees among noisy and quiet work spaces, as to safeguard them from long exposures to noise.
Sometimes, administrative and engineering controls alone are effective in reducing noise and solving the problem.
When are employers required to provide HPDs?
If administrative and engineering controls are not feasible, practical, or sufficient to reduce workplace noise to acceptable levels, the employer must fit employees with appropriate hearing protection.
Under OSHA, employers are required to provide hearing protection to all workers exposed to 8-hour TWA noise levels of 85 dBA or above, and use of hearing protection is mandatory at levels above 90 dBA. At least one type of earplug and one type of earmuff are to be available to workers.
How do I find the right hearing protection?
Diverse scenarios condition the selection of the most appropriate HPDs. When choosing hearing protection for your workers, it’s important to take into consideration a few key aspects:
1. The environment. Climate influences the selection of HPDs – earmuffs are generally more suitable in colder climates, for instance. The type of work being performed should also be considered: Is communication required or the noise intermittent, causing frequent donning and removal of hearing protection? Do the workers handle materials that are dusty, oily, corrosive, or caustic? Is detectability of foreign material in the process necessary? What other PPE is required to be worn with the hearing protection?
2. The Noise Reduction Rating (NRR) is an estimate of the average sound level reduction or attenuation provided by an HPD in a laboratory environment. It is not an accurate predictor of an individual’s protection from noise exposure. NIOSH recommends subtracting 7dB from the NRR, if noise is measured on a dBA scale (A-weighted decibel scale), and division of the result by 2. The NRR derating scheme can be found in ANSI’s CSA Z94.2-14 Hearing Protection Devices Standards. However, all derating schemes come up short as none tells the individual user his/her actual attenuation.
3. The user’s personal attenuation rating (PAR) from individual fit testing. The PAR is an actual attenuation value measured for an individual earplug fitting., HPD fit testing is an OSHA Best Practice and is currently the only way know how much attenuation an individual worker is capable of receiving from his or her hearing protection.
4. Ease-of-fit and in-ear comfort for workers. This has a heavy impact on the effectiveness of an HPD. If the hearing protector isn’t comfortable, it is less likely to be worn—or worn correctly—and provide the noise reduction it was designed to offer.
Types of earplugs
Earplugs provide an air-tight seal of the ear canal. They come with different attenuation ratings (NRRs) for different noise levels.
They can be either disposable (single-use) or reusable (multiple use).
Foam earplugs are affordable, effective and easy to use. They conform to the shape of the ear canal and change shape dynamically to accommodate jaw movement from chewing, talking, etc. That’s what makes them particularly effective and one of the reasons they provide the highest attenuations of any HPDs.
Banded earplugs are connected by a flexible band and are suitable for people who move in and out of noisy areas. They are worn under the chin can be easily stored around the neck when not in use.
Detectable earplugs are designed for high-visibility and detectability by a variety of methods in processing environments where foreign material contamination must be avoided.
Regardless of the material, earplugs are most effective when the wearer has been properly trained on use and insertion. Read further to learn about how to achieve correct fit.
Made from rigid cups with soft cushions that seal around the ear, earmuffs come in a variety of shapes and sizes. Three common designs include: over-the-head, cap mounted and behind-the-neck.
To block noise effectively, a tight seal between the ear cushion and the head is critical. Gaps provide an easy path for sound to bypass the earcup, thus reducing the amount of attenuation provided by the earmuff.
Here is a useful video on how to achieve proper fit with earmuffs.
Why choose an earmuff over an earplug?
It’s easier to achieve proper fit with an earmuff, but earplugs typically provide higher noise reduction if used correctly. Obtaining correct deep insertion of an earplug is more challenging. Other advantages of earmuffs include convenient wearing during exposure to intermittent noise and more warmth in cold environments. Earmuffs can also be worn with hearing aids and are longer lasting. However, by comparison, earmuffs may become uncomfortable when used for longer periods of time and may be incompatible with other PPE such as hard hats or eyewear.
In some situations, PPE needs to preserve situational awareness and remain communication-friendly, preserving speech while protecting hearing.
Depending on the work environment, any hearing protection that reduces sound levels far below the OSHA-defined 85 dBA action level and interferes with communication may be considered overprotecting. The ideal HPD reduces hazardous noise levels to a safe range without overdoing it.
The best hearing protection devices have no value if they are not worn. Getting workers to wear HPDs starts with helping them understand the long-term implications of NIHL.
Here are some tactics to help workers start caring and become experts at identifying the early warning signs of NIHL:
- Discuss with employees their annual audiograms and explain the results
- Publish information on noise and noise levels
- Use audio demonstrations to illustrate the impact of hearing loss
- Use older, experienced employees as teachers and advocates: “When you teach, you learn twice”
- Reward workers who comply and assist their colleagues
- Encourage workers to take HPDs with them for use at home
One-to-one trainings are also effective in educating workers on how to use and maintain PPE.
By the way, here is a quick guide. on how to clean and care for hearing devices.
When it comes to timing, many employers find that the most effective time for administering hearing conservation training and fit testing is in conjunction with the annual audiometric testing, when the worker is tuned into his personal safety and health.
Finally, always make sure your program is running smoothly by constantly evaluating performance – asking for employee feedback, and reviewing responsibilities and records.
Hearing conservation is a serious issue. We're here to help. Here is a list of useful resources to help you get started in building a hearing conservation program within your organization.