Not Your Grandpa's Ear Muffs

Advances in passive hearing protection improve comfort, fit, and function.

• By Lisa Steckert
• Mar 01, 2019

This month marks the 146th birthday of the ear muff, first invented to keep Chester Greenwood's ears warm while skating in Maine. But by 1884, ear muffs were designed to deliver hearing protection for soldiers and sailors, then underwent further innovations to protect against jet engine noise during the Second World War.¹ Fashioned with stiff cushions and a strong headband, their nascent design was said to deliver a vicelike grip.

Today, ear muffs are arguably one of the most vital forms of industrial personal protective equipment. While ear muffs have long served to protect individuals from excessive noise and its damaging effects on hearing, the ways in which they do so are constantly evolving to afford workers improved comfort, fit, and function.

We rely on our sense of hearing both in and out of work to communicate, conduct tasks, experience the world, and stay safe. But excessive noise—a hazard faced by 22 million U.S. workers each year²—presents a permanent risk to our hearing and overall well-being. In fact, noise-induced hearing loss (NIHL) is the single most common permanent and preventable occupational injury.³

When you consider the toll hearing loss takes on individuals, business, and society, it's easy to see great value in preserving workers' hearing. Now, as we celebrate the ear muff's anniversary, is the perfect time to look at the latest advances in passive hearing protection. By making informed selections and taking advantage of new technologies, you can help each of your workers find the passive ear muff that's right for them—and ensure they return home day after day, decade after decade, with their hearing intact.

Impacts of Workplace Noise
When ear muffs were first designed as hearing protectors, the relationship between noise exposure and hearing loss seemed simple and was not well understood. Today, however, the effects of working in excessive noise are understood in much greater detail—and the cost of NIHL is much greater than previously believed.

Noise is considered loud (i.e., hazardous for humans) when it reaches or exceeds 85 decibels for more than eight continuous hours. ⁴ The effects of exposure to loud noise are multifaceted. For starters, noise at work can create physical and psychological stress, reduce productivity, interfere with communication and concentration, and contribute to workplace accidents and injuries by making it difficult to hear warning signals.⁵

One-time exposure to high-intensity impact or impulsive noise can lead to temporary effects such as a change in hearing (muffled hearing or a stuffed-up sensation) or tinnitus (ringing in the ears). Impulse noise of sufficient intensity can cause instantaneous permanent hearing loss and tinnitus.

Long-term exposure to continuous loud noise may cause permanent hearing loss, which may be incurable by surgery or hearing aids. NIHL is unlike most injuries because it’s often painless and progressive. In fact, it often goes unnoticed until irreversible damage has occurred. Yet once incurred, NIHL has a significant bearing on an individual's overall well-being. A loss in hearing may limit the ability to understand speech, impair the ability to communicate, reduces productivity, lead to social isolation and withdrawal, or increase the risk of high blood pressure and high cholesterol. ⁶

The cost to employers and society is huge, as well. U.S. companies pay $1.5 million annually in penalties for not protecting workers from noise, while a whopping $242 million is spent annually on workers' compensation for hearing loss disability.⁷

To address hazardous noise at work, the Occupational Safety and Health Administration's regulation 29 CFR 1910.95 calls for hearing protection to be provided by employers wherever noise averages more than 85 decibels during an eight-hour day. Noise measurements are based on a time-weighted average and all continuous, intermittent and impulsive sound levels from 80 decibels to 130 decibels are factored in. Refer to the OSHA regulation for complete details.

While painless, progressive, and permanent, occupational NIHL is also preventable with today's hearing loss prevention strategies and technology.⁸ Providing effective hearing protection to every noise-exposed worker is vital, but even the highest-attenuating hearing protection is useless if workers do not wear it. Here's what you need to know to find a comfortable, effective solution.

Anatomy of a Passive Ear Muff
A passive ear muff is comprised of four basic components. The cup is a rigid, molded plastic piece visible to others when worn. It is the outer shell to which the rest of the ear muff is attached, and the user's ears should fit entirely inside the cups.

The cushion is the foam circle that fits around the user's ear and creates the interface with the wearer's head. Passive ear muffs rely on the quality of the cushion to deliver attenuation. A good interface of the cushion to the head around the ear is needed to create a seal. Poor cushion material that delivers a loose or broken seal renders the user unprotected from noise.

Inside the cup and located behind the cushion is another layer of foam specially designed to interrupt sound waves transduced through the ear cup. Finally, the headband holds the ear muffs in place and delivers the pressure that creates the cushions' tight, protective seal. When the headband delivers too much force, the user will experience uncomfortable pressure; too little leaves hearing unprotected.

Advances in Passive Ear Muffs
As with most types of personal protective equipment (PPE), an ear muff that is uncomfortable is more likely to be removed or unworn, even in the presence of hazards. Providing comfortable hearing protection is key, but finding passive ear muffs that feel good over long shifts and fit every worker's unique dimensions (head size and shape plus ear size, shape, and location) can prove challenging. Fortunately, new advances make it easier than ever to deliver comfortable, properly fitting hearing protection to the entire workforce.

Weight is a top consideration in selecting comfortable passive hearing protection devices. Because ear muffs are generally worn over the head, they can feel heavier the longer they're worn, especially when used in combination with other forms of above-the-shoulder PPE.

Innovations in headband styles are driving weight reduction. Headbands are made of tempered steel or molded plastic, each designed to retain its shape and deliver sufficient force. But beyond their foundation they vary greatly, from overmolded bands (steel coated in pliable plastic) and wires covered in padded textiles, to completely non-metallic (dielectric). Look for a headband with the level of resilience and interoperability that meets the specific application. Then, select those with lightweight design and materials to support long-time wear.

Headbands are also the site of new adjustment features that help individuals find a personally comfortable fit for their unique dimensions and work position. Poorly fitting ear muffs can slip out of place, rub, and create pressure points—and are likely to be removed. In addition to convenient sizing options on headbands, new features allow users to make micro adjustments to move the cup forward and back using slip fit, step and click, or ratchet mechanisms and achieve just-right placement.

Cup size is another area experiencing innovation. Historically, larger cup sizes equated to higher attenuation ratings. But a larger-than-necessary cup adds bulk and weight and reduces comfort. Technical advances in airflow control allow some cups to be much smaller in size and lighter in weight while delivering very high attenuation ratings.

The cushion is key to ear muff performance. It delivers the protective seal around the user's ears as well as attenuation. It also regulates the amount of pressure the user feels on his or her ears from the foam inside the cup. A poorly constructed or poorly attached cushion, or one whose foam is too dense, yields a poor-quality seal, little to no attenuation, and an uncomfortable fit. New seal technology yields big improvements in both comfort and protection. Pay close attention to the cushion's foam density and pliability and select cushions with high-quality foam securely enclosed in soft, non-abrasive plastic coverings to ensure all-day comfort and attenuation.

The best passive ear muff is the one that delivers the most comfort all shift long. Recent advances make today's solutions more comfortable and reliable than ever before, and even more innovation is just around the corner. When you're familiar with the latest offerings in ear muff materials, design, and technologies, you can confidently outfit your workforce with well-fitting and reliable solutions that protect each worker's invaluable, irreplaceable sense of hearing.

References
1. https://asa.scitation.org/doi/10.1121/1.2024272
2. https://www.cdc.gov/niosh/topics/noise/default.html
3. https://www.nidcd.nih.gov/health/noise-induced-hearing-loss#6
4. https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html
5. https://www.osha.gov/SLTC/noisehearingconservation/healtheffects.html
6. https://blogs.cdc.gov/niosh-science-blog/2018/06/28/noise-effects/
7. https://www.osha.gov/SLTC/noisehearingconservation/
8. https://blogs.cdc.gov/niosh-science-blog/2018/06/28/noise-effects/

This article originally appeared in the March 2019 issue of Occupational Health & Safety.