Along with disposable ear plugs and moulded ear plugs, earmuffs are a type of Personal Hearing Protection Device (PDHP). Unlike earplugs, which are inserted into the ear canals, earmuffs are placed over the ears and are connected by a head band that goes over the top of the head. They reduce the surrounding noise by way of the two shells that cover the ears of the user in order to insulate them. This type of hearing protection has certain advantages:
- Ease of use: instant protection with no obvious risks.
- Reusable and can even be shared if cleaned correctly: In a workplace the same set of earmuffs can be shared between workers.
- Affordable: A simple set of earmuffs costs between $15 and $60 each, but some models can exceed a few hundred dollars.
- High attenuation: Ear muffs commonly attenuate between 26dB(A) and 35 dB(A).
With these kind of advantages it is easy to see why so many people turn to ear muffs for all types of work in noisy environments, whether for professional use (metallurgy, aviation, construction, etc.) or personal (gardening, DIY, concerts, etc.).
SUMMARY
While it is undeniable that for a specific use this type of Personal Hearing Protection Device is sufficient, the limitations of earmuffs are evident when it is necessary to be protected from noise throughout a work day without constraint.
Let's take a closer look at three key features that Personal Protective Equipment (PPE) must offer to be accepted and utilised effectively by your employees: comfort, communication and adaptability.
Are Ear Muffs comfortable?
PPE that is not comfortable will not be worn by your employees for the whole day at work. If an employee feels uncomfortable while wearing it, they will be tempted to remove their hearing protection. The risk of hearing loss is therefore considerably increased because a PHPD that is not worn 100% of time exposed to noise is not effective.
In terms of comfort, earmuffs start to show their limitations.
Weight of earmuffs
Made mostly of stainless steel, PVC and other resistant materials, a passive noise cancelling headset weighs on average between 200 and 600 grams depending on the level of attenuation it provides. Indeed, the higher the attenuation, the greater the amount of foam or liquid needed for the insulation; therefore, the weight increases. This weight may seem irrelevant for one-time, short-term use, but becomes much less so by the end of an 8-hour workday.
The so-called "active" anti-noise helmets, which have one or more microphones placed on the shells to amplify or eliminate in real time the surrounding noise, are heavier because of this embedded technology. Their weight increases even further when you want to communicate in noise by the addition of another microphone, batteries, etc.
A fragile balance between insulation and compression
To protect effectively from a noisy environment, an earmuff must exert constant pressure on the ears of the wearer to create a permanent seal. Indeed, the slightest leakage significantly reduces the effectiveness of the protection, thereby increasing the risk of hearing loss. This is why it is not recommended to wear earmuffs over a hat.
Because of this permanent seal, a feeling of pressure can often be felt after several hours of use. This uncomfortable sensation may cause the user to remove the headset for relief, again posing a risk to hearing.
Ear muffs in extreme conditions
The use of ear muffs is often associated with extreme noise conditions. Indeed, it is the only protection that can be used as a second layer of insulation in cases where double hearing protection is necessary, i.e. when a single type of PHPD does not allow attenuation to fall below the threshold of 80 dB (A).
When worn in hot conditions, earmuffs negatively affect the comfort of the wearer. The pressure exerted by the pads on the ears leads to sweating and heat that make ongoing wear difficult.
Communication in noisy surroundings
The ability to communicate in noisy environments is another essential requirement in the selection of a Personal Hearing Protection Device that is best suited to the needs of your employees.
High attenuation and the need to communicate
Ear muffs commonly attenuate between 26dB(A) and 35dB(A) and are suited to environments in which sound intensities are high. In these conditions, it is difficult to communicate without removing the protector from the ear.
According to Australian Standards, if employees remove their hearing protectors for just 2 minutes, while exposed to noise in an 8 hour workday, their hearing protection loses 25% of its effectiveness. If they remove them for 2 hours while exposed to noise, the loss of efficiency increases by 75%.
Depending on the activity, not wearing hearing protection, even for a short time, can have serious consequences for hearing, as reported by a member of a French law enforcement unit who used noise cancelling headphones before choosing Cotral Lab moulded plugs:
"During our firing range sessions, we equipped ourselves with anti-noise helmets to protect us, but there are often problems due to a shot at the wrong time. [...] During an exercise, a grenade exploded and since then, I have suffered from permanent tinnitus."
When we need to communicate, PHPDs aren't equal.
Adaptability
Giving your workforce the same type of PHPD is like giving them all the same sized safety shoes: only a few people will be happy. To ensure that hearing protectors are accepted and worn by your employees they must align with their individual needs.
Adaptability to a noisy environment
Using an PHPD that has too great an attenuation compared with -the surrounding noise will protect against harmful noise, but equally will isolate the employee from sounds essential for safety, such as fire alarms, the approach of trucks and also from the machines on which he or she works.
Take the example of an employee in a logistics warehouse, working in an noisy environment averaging 90dB(A), who has been given a set of earmuffs with an attenuation of 30dB(A). The employee perceives his surrounding noise at 60dB(A) and finds that he is overprotected.
It is therefore vital to understand the levels of noise to which your employees are exposed before choosing the best PHPD with which to protect them.
Compatibility with other PPE
Although there are theoretical solutions for combining Personal Protective Equipment, in reality the compatibility of Ear muffs and other PPE can be problematic depending on the combination of items required (noise-cancelling headphones + safety goggles, helmet + headband + mask, etc.). When safety glasses are worn with the earmuff, it breaks the seal between the earmuff and the side of the face, thereby decreasing the effectiveness of the earmuff. The protection achieved will be far less than what the user thinks they are achieving. This can reduce a class 5 earmuff down to a class 3 earmuff.
In all cases, the question of comfort during prolonged use must be considered, particularly when in combination with other forms of PPE worn by your employees.
Conclusion
For occasional use or in extreme conditions where communication is not a necessity, Ear muffs can be a viable solution and are preferable to disposable ear plugs because of their ease of use. On the other hand, for everyday use where communication is a determining factor, it is highly recommended to consider another type of PHPD.