How the Ear Works
The auditory system is one of the most complex bodily functions in humans, but we can generally break it up into two parts:
- Peripheral: The peripheral system includes the outer ear, middle ear and inner ear, each of which has a unique role. The outer ear has three parts within it — the ear canal, the pinna and the eardrum. Next, the middle ear consists of three small bones called the incus, malleus and stapes, collectively referred to as the ossicles. These tiny bones are how the outer ear and inner ear connect. Finally, the inner ear is in charge of controlling both our balance and our hearing. It consists of the cochlea, which connects to the central auditory system and contains sensory cells that are crucial in the process of hearing.
- Central: Though it is much smaller than the peripheral hearing system, the central hearing system is still an essential part of our auditory experience. It is responsible for connecting the auditory nerve to the auditory cortex of the brain via a pathway through the brain stem. This system enables us to not only hear sounds but to also interpret them.
The sound waves that come from the various machinery, vehicles and tools in your workplace are vibrations in the air that travel through the ear canals and cause our eardrums to vibrate. Since the eardrum is so sensitive, it can pick up even the slightest noises, and intense sounds are difficult for it to take in repeatedly.
Interpreting Sound Waves
The process of interpreting sound waves starts at the tiny chain of bones in the middle ear, then travels into the inner ear’s cochlea. The cochlea has fluids within it that move due to the vibration of the sound wave, which activates our “hair cells.” These tiny organisms will then react to the sounds based on their frequency — this means high-pitched and low-pitched sounds will be interpreted differently and in different parts of the cochlea.
Auditory Nerve Impulses
The next phase is where the real interpretation of these sounds begins — it’s where we begin to assign meaning to different noises based on their sound waves and frequencies. Each of those microscopic “hair cells” will pick up on a sound’s frequency, then generate a response via auditory nerve impulses. These impulses then travel to the auditory cortex of the brain via the brain stem, which will translate them into a meaningful sound.
This entire process happens almost instantly — the time it takes for something to create sound waves and then travel to our brain is a fraction of a second.
Dangerous Noise Levels and Their Damaging Effects
Due to the sensitivity of the ear and the intricacy of the auditory system as a whole, humans must understand dangerous noise levels and their damaging effects. Avoiding excessively loud noises will help keep your ears healthy and well-functioning for as long as possible. That is why it’s vital to be able to address and mitigate dangerously loud noises in the workplace. Keeping your staff safe should always be your top priority as a business owner or manager.
Experts say hearing damage can occur from any noise level higher than 85 decibels, which is comparable to heavy traffic. As the decibels increase, so does the risk of hearing loss. On top of this, people who experience prolonged exposure to excessively loud noises will have a much higher potential to develop hearing problems. A general rule of thumb is to never take in sounds that are above the decibel threshold for longer than two minutes.
Hearing Loss Precautions & Protection
While those numbers and suggestions are practical for the average person, employees who are working in an abnormally loud environment should take extra precautions to avoid permanent hearing loss. A study by the National Institute for Occupational Safety and Health (NIOSH) analyzed U.S. workers to identify how many encounter dangerous noise levels in the workplace. They found hazardous noise levels affect about 22 million workers in America, and that hearing loss accounts for around $242 million of the nation’s workers’ compensation payments annually.
In a follow-up study, the NIOSH found that of those 22 million workers, 23% of them went on to experience significant difficulty hearing. Another 15% have tinnitus, a condition that leads to a continuous buzzing or ringing in the ear, despite a lack of sound. People can experience tinnitus in one or both ears. A separate 9% of the workers in the study suffer from both tinnitus and hearing difficulty. These statistics make hearing loss and auditory issues among the country’s most common work-related health issues.
Noise Level Regulations From OSHA
To protect American workers, the Occupational Safety and Health Administration (OSHA) enforces limits on the noise levels workers should encounter during their eight-hour days. Here’s how the formula works:
- An employee or contractor working a full eight-hour day can get exposed to no more than 90 A-weighted decibels (dBA).
- For every additional five dBA, the length of a worker’s exposure decreases by 50%.
- For example, if the noise level increases from 90 to 95 dBA, four hours is the longest a worker should be around the source of the noise.
These, of course, are general guidelines, and the exact time of exposure and decibels your staff will experience depend on your industry and work environment. The NIOSH study also found the risk of hearing damage is higher for workers in specific sectors and professions. The manufacturing and mining sectors especially had increased risks for the frequency of dangerous workplace noise exposure and the chance of experiencing hearing difficulty in the future. No matter the type of work setting, though, these types of long-term hearing loss are irreversible, and hearing aids or surgery cannot treat them. Workers may also experience side effects such as:
- Mental and physical stress
- Decreased productivity
- Difficulty communicating and concentrating
- Increased occurrences of work-related injuries and accidents
Recognizing the Warning Signs of Hearing Loss
As you can see, the effects of long-term hearing loss and dangerous workplace noise levels are significant and difficult to avoid without addressing the issue at its root — by either lowering the noise levels at your workplace or reducing the amount of time your workers must hear hazardous noises. Luckily, there are typically several warning signs your staff is struggling with the noise levels at your place of business, such as:
- A humming or ringing in their ears at the end of the day
- Having difficulty hearing a co-worker or manager who’s standing close to them
- Experiencing spurts of temporary hearing loss, whether they are brief or prolonged
Industrial Noise Control Benefits
Controlling noise levels in the workplace does more than eliminate hazards. It also offers a number of advantages to your workforce. Effective noise control in industrial settings often contributes to:
- Increased productivity and efficiency: While some people find that music or other background noises enhance their focus, loud industrial noises are unlikely to contribute to anyone’s focus. By keeping noise levels to a minimum, on-site staff can choose to work in quiet or with background sounds they know contribute to their productivity. Without excessive noise serving as a distraction, staff can keep their focus where it needs to be and become more productive and efficient during their workdays.
- Better employee retention: Over time, excess noise can become more than an irritant. Some people may become so bothered that the noise overshadows all the work they do for you, leading them to decide to leave and find employment elsewhere. Minimizing sound distractions means minimizing the reasons your staff may have to seek new employment, boosting staff retention over time.
- Improved staff health and safety: High noise levels can lead to both short- and long-term issues, including hearing loss, tinnitus, migraines and other health concerns. Keeping noise levels low eliminates the possibility of these problems occurring.
- Enhanced communication and concentration: Lower noise levels can mean better focus among staff. The more work they do, the more likely it is that they will have to collaborate or communicate with other people around them. Maintaining workplace noise standards allows your people to connect with one another more effectively without distracting others.
- Regulation compliance: By making sure your property’s noise levels are in accordance with OSHA regulations, you can avoid fines and citations while gaining recognition for being OSHA-compliant.
Noise Hazards and Control Measures
The effects of excessive noise on health are well-documented. What can you do to ensure your business is minimizing sound hazards everywhere possible? First, you must consider where your noise pollution is coming from. In industrial settings, the source is often machinery, though other common sources are the manufacturing process and overzealous communication. Once you identify your sources, you can begin implementing specific processes to mitigate them, such as:
- Personal protective equipment (PPE): Ear plugs and headphones are some of the best protective options for staff working around loud machinery, especially if there are no other options to reduce their noise levels. When you introduce these staff-based noise reduction tools, be sure to train your staff on how to use them properly for maximum auditory protection.
- Engineering controls: In some cases, especially with newer machine models, there may be control settings you can adjust to minimize noise without affecting workflow. Check your equipment settings and consult with professional engineers to see if there are ways for you to lower sound levels right at their source.
- Administrative controls: Another avenue you could pursue is implementing administrative rules, such as limiting staff members’ time in noise-heavy areas or requiring PPE during specific operations. Managers and noise specialists should feel empowered to develop rules and standards that help their employees stay safer in the workplace.
How to Reduce Workplace Noise Exposure
Although they are more prevalent in some industries than others, hazardous workplace noises exist in more workplaces than construction sites and manufacturing facilities. People working in restaurants, offices, call centers, schools and more are all at risk of experiencing prolonged exposure to dangerously loud noises.
So, how can business owners and managers work to reduce their staff’s exposure to excessively loud noises? Here are a few tips from OSHA and other reputable workplace safety organizations:
- Lower the noise levels: If possible, the most direct way to address high-decibel noises at the workplace is to use engineering controls to decrease the noise levels. You can accomplish this by lowering the decibels at the source or as they travel from the source to the ear. This solution is not always possible, depending on the tools and devices needed to complete tasks, but things you can try include switching to low-noise tools, addressing any maintenance issues with your equipment or using sound walls or curtains to enclose the source of hazardous noises.
- Limit employee exposure: On the administrative side, you can keep your employees safe by limiting the length of time an individual can spend near the source of high-decibel noises. You can also provide soundproof rooms for workers to recover from loud noises during breaks.
- Provide hearing-protection devices: For deafening work environments, sometimes decreased length of exposure isn’t enough to protect your workers. It might not be possible to lower the decibels of the noise sources at your workplace, either. In these cases, OSHA recommends providing your staff with protective hearing devices such as earplugs or earmuffs. If you do need to use this method, be sure you attempt to make engineering and administrative changes first, as protective hearing devices are typically not as effective on their own.
- Train your staff to recognize dangerous noise levels: Often, the upper-level management and owners of a workplace are not in the thick of it every single day like your staff is. It is, however, the responsibility of higher-ups to train workers on when to speak up about excessively loud noises. Give your team the tools to be able to recognize dangerous noises in their work environment, so they know when it’s appropriate to inform you of them. You should also provide your staff with information about OSHA’s recommendations on the relationship between decibel levels and exposure time, as we discussed above.
- Invest in regular occupational noise testing: The final tip to protect your staff from long-term hearing loss is to monitor your noise levels regularly so you can act fast to correct them. Even if you correct hazardous noise levels, you should continue to monitor for any changes you may need to adapt to. It’s always best to stay ahead of dangerous occupational noise levels to keep your workers as safe as possible. After all, if you end up having to establish a hearing test program at your workplace, it’s likely some of your workers have already experienced some damage that puts them at risk of developing long-term hearing problems.
Integrating Noise Control Into EH&S Management Systems
Implementing workplace noise standards is only the start of managing your environment, health and safety (EH&S) standards in regard to sound. Even the best-laid plans require consistent monitoring and surveying to ensure the application is going as planned. Keep these tips in mind as you integrate your strategies:
- Use multiple acoustic minimizing methods: Noise mitigation is often completed in three ways — absorption, blocking and covering. Use strategies that employ each method and see which ones are most beneficial for your job site.
- Create workplace noise surveys: Get information on how your guidelines are working straight from your staff. These surveys can give you valuable information on how your standards may help or hinder your staff.
The Purpose of Occupational Noise Evaluations
By investing in occupational noise evaluations at your workplace, you’re showing your staff that you care about their long-term health and safety. Occupational noise testing has several benefits, such as:
- Getting ahead of and potentially avoiding expensive or time-consuming solutions to sources of hazardous noises
- Staying abreast of the maintenance of noise-producing equipment and tools
- Knowing the status of your workplace noise levels
- Being proactive about keeping your workers safe
Investing in regular occupational noise evaluation is so valuable that OSHA has specific testing requirements for employers who provide their staff with hearing protection devices. These employers must offer their staff auditory tests at the following points:
- Within three months after starting to work with the hearing protection
- Anytime a health and safety representative requires it
- Annual for individuals having a standard threshold shift (STS)
- At least every two years, as a standard practice
Occupational Noise Evaluations Levels & Tools
Occupational noise evaluations test the levels in a work environment to ensure they do not equal or exceed about 85 decibels, which is the maximum level a worker can encounter during an eight-hour shift. For a 12-hour work shift the action level is 82 decibels. A sound level meter and a noise dosimeter are two tools used to evaluate a person’s exposure to dangerous noise levels. You can count on a reliable workplace health and safety company such as TRC to provide these services. You should invest in noise level testing regularly, and especially when you make changes to your production process, tools or equipment.
When you conduct annual audiometry testing, look for specific figures to ensure your employees are safe at the workplace. Be sure to conduct the first audiometry exam within a worker’s first six months at your office or another workplace to serve as a baseline for any changes that may occur due to noise exposure. You can use the results from this initial audiogram to determine if an employee is suffering from exposure to hazardous noise levels as they continue to work for you. Conduct tests at several frequencies — 500, 1,000, 2,000, 3,000, 4,000 and 6,000 Hz — for each ear for the most accurate and inclusive results.
If any employee’s audiogram results are alarming — whether during the initial exam or a follow-up test — it is your responsibility as the employer to notify them in writing within 21 days after verifying the results. This step is especially vital if a significant change in hearing has occurred in a short amount of time.
Contact TRC Today
If you’re ready to start addressing the noise levels at your workplace, you need a team of professionals who is ready and willing to help you analyze and adjust them. You can request a quote for workplace noise survey and consulting services from TRC. We are the experts at all things related to noise exposure control. We’ll come to your workplace to conduct quantitative measures of your noise levels, then provide effective solutions to this issue.
Keep browsing our site to learn more about our occupational noise evaluations, which can address noise-related issues such as vehicle traffic, ventilation and dust collectors, cooling towers, grinding equipment and more
