In this episode of the global Science of Safety Podcast, co-hosts Mark Reggers and Laurie Wells are joined by guest Eric Fallon, Doctor of Audiology and retired lieutenant colonel from the US Army. Eric is a technical specialist supporting protective communications with 3M Personal Safety Division. The discussion addresses complex situations that require the ability to hear sound and / or communicate while protecting the worker from the hazardous noise.
Tune in to listen about how the characteristics of the noisy environment might affect hearing protector choices and how different technologies support helping certain sounds to be heard while being protected.
Concepts discussed include:
- Overprotection,
- Hearing protector features: level-dependent, environmental listening, and noise-canceling microphones,
- Conducting walk-throughs to observe the communication needs of workers.
Example of these common workplace scenarios are provided to highlight how these technologies can be used.
This global podcast series provides another educational tool that can help increase your knowledge and is something that you can share with others in your organization and with your friends. The goal is to help provide a global perspective and foundation for those of you who are new to workplace health and safety and personal protective equipment (PPE) while also providing information for more experienced professionals who handle complex health and safety challenges.
You can listen, subscribe to, and share this podcast through Apple Podcasts, Spotify, Google Podcasts, Stitcher, and most major podcast apps and platforms.
If you have any questions or topic suggestions, you can get in contact with this podcast
by contacting your local 3M office or visit our worker health and safety website at 3M.com. If you’d like some assistance in your workplace when it comes to the appropriate selection, use, and maintenance of PPE please contact us today.
Around the world, we aim to help everyone get the job done safely today, tomorrow and in the future.
Below is the full transcript of the podcast:
Presenter:
The 3M Science of Safety Podcast is a free publication. The information presented in this podcast is general only, should not be relied upon to make specific decisions. Listening to this podcast does not certify proficiency in safety and health. You should always seek the advice of a licensed or certified professional in relation to your specific work or task.
Always consult the user instructions for any personal protective equipment you are using and follow local laws and regulations. Information presented is current as of the date of the podcast and requirements can change in the future. 3M owns all rights to the podcast, and any reproduction is strictly prohibited without permission.
Laurie Wells:
Welcome back to our previous subscribers, and welcome to our new listeners. The Science of Safety Podcast is presented by the 3M Personal Safety Division. This is a podcast that is curious about the science and systems behind workplace health and safety, with a focus on Personal Protective Equipment, or PPE, used to help keep workers healthy and safe.
I am Laurie Wells, one of your cohosts. And I have the great pleasure to have Mark Reggers with me as well. We are occupational health and safety professionals who like to ask questions– why, how, and please explain. Whether you’re a safety professional, occupational or industrial hygienist, someone with any level of worker health and safety responsibility in your workplace, a user of PPE, or a health and safety nerd like us, this is the podcast for you.
Laurie Wells:
Hey, Mark. Can you hear me over there?
Mark Reggers:
I certainly can, Laurie. I can hear you loud and clear, but not so loud. I haven’t had to have my volume too loud to give myself some noise-induced hearing loss with my headphones. But it’s amazing, isn’t it? The other side of the world, your audio is excellent.
Laurie Wells:
As is yours, Mark. I can hear you really well. But I’m thinking about if we were in a different work setting, sitting in a factory with lots of high noise and machinery and equipment, how well could we communicate then?
Mark Reggers:
It would be a challenge. And that is a challenge that many industries and many workplaces deal with on a daily basis.
Laurie Wells:
Absolutely. And a great segue to our topic today, which is about complex noise environments, how to hear and communicate with each other but still be protected when working in loud noise.
Mark Reggers:
As always, we have invited someone with a great deal of experience to talk to today about this very challenge that workplaces face. So, I’m so pleased to introduce our 3M colleague, Dr. Eric Fallon. Welcome, Eric.
Eric Fallon:
Hi, Mark and Laurie. I’m so happy to be here with both of you today.
Mark Reggers:
So Eric, can you share a little bit more about your professional background, your role at 3M, and how is that important to your day-to-day work?
Eric Fallon:
Sure. I started my career in the US Army as a private in a combat specialty, and after a few years, made my way to college in the field of audiology in which I hold a doctorate degree today. I wound up serving for 25 years in the Army in a wide variety of roles, including serving as the US Army Hearing Conservation Program manager. And my final assignment was as the director of audiology, speech, and research at Walter Reed National Medical Center in DC. And now I’ve been with 3M as an application engineer for 12 years.
During my Army career, back to that, I also had several operational assignments, such as commanding an airborne unit. And I also had multiple combat deployments where I would find myself in very complex acoustical environments, which could transition from very quiet to extremely loud on a moment’s notice. The challenge with that type of complex sound environment is that the hearing and communication demands in quiet were not conducive to wearing hearing protection. But when the noise environment would transition, there often was not adequate time to employ and fit my hearing protection.
Another challenge I faced during my time in the military that I believe helps me now is my firsthand experience with communicating via radio in very loud military noise environments. So it’s those experiences in conjunction with my training as an audiologist that I feel have helped me in my role at 3M in assisting customers with some of the same challenges and needs as I’ve experienced.
Laurie Wells:
Well, you have a unique and interesting career, Eric. And I want to thank you so much for sharing your insight today with our listeners. Before we get too deep into the topic, though, I do want to remind people who are listening that we have covered some hearing protector topics on three previous podcasts, so please be sure to check those out. Today, we want to explore some of the more complex situations, like we described, helping people communicate with each other and hear what’s around them while they’re working in hazardous noise. So Eric, let’s start off by having you describe this challenge in a bit more detail.
Eric Fallon:
Happy to. Let’s start off talking a little bit about noise. We often describe noise exposure by a single number, right? An exposure averaged over time, like a Time-Weighted Average, or a TWA, depending on the local regulatory requirements for measuring noise exposure.
However, the reality is that noise levels can fluctuate a great deal. And that fluctuation could come in the form of either intermittent noise, where there may be periods where there is little or no noise, intermixed with periods of hazardous noise. Or it could be fluctuating noise, where the noise is always present and maybe even hazardous, but at varying levels. And so, it’s really important to understand the role that the type of noise and the noise environment plays when we start talking about communicating in noise.
Laurie Wells:
So you’re saying that one number, that average number may not actually represent the need for the noise reduction over the whole work time or the work experience.
Eric Fallon:
That’s right. And another challenge that I often see are hearing protectors that offer attenuation at levels that are much higher than the measured noise levels would require. And by hearing protectors, I obviously mean those that are issued. And while this might seem like a safe way to ensure that the worker is protected, regardless of what the noise exposure is, certainly if it goes a little bit lower, it can lead to what we call overprotection, which may degrade the worker’s hearing ability to a point that they actually remove the hearing protectors to hear sounds that they deem important in their environment.
Mark Reggers:
And I can see why there may be that tendency to overprotect workers with a high-attenuating hearing protector, going straight to the top, and how challenging it may be to select correct hearing protector for a noise-exposed worker when you factor in all these demands into one single product.
Eric Fallon:
Being able to hear while being protected from hazardous sounds can be a challenge. And obviously, the purpose of using hearing protectors is to reduce the sound, to reduce the hazard, if you will. And in many situations, that’s exactly what the worker needs. They may not have a big audibility or communication need in their work environment. But there are times when reducing sounds too much limits how well people can hear important sounds that are critical to doing their job, or in some cases, maybe even affecting their safety. And unfortunately, sometimes an employee may be tempted to adjust the fit of their hearing protector, or they might even choose not to wear a hearing protector at all if they feel like it degrades their hearing too much.
Laurie Wells:
Well, that makes sense. And communicating on the job is such a common need.
Eric Fallon:
It certainly can be, whether it’s work-related or just communicating with your coworkers. My advice to safety professionals with hearing conservation responsibilities is to perform what I call an audibility and communication assessment for their noise-exposed employees and work areas. This assessment can be as simple as walking through the different noise environments and observing how employees are using their hearing and notice if they may be removing their hearing protectors to hear.
Some common things that you may see in one of these assessments are employees having face-to-face conversations. You should look and see if that’s easy for them. They may be trying to listen to their equipment that they’re operating to ensure it is operating correctly. Or they may be trying to monitor a radio while they’re working in hazardous noise.
One thing I often notice are employees that are assigned radios. And they will have a lapel or a shoulder mic attached to the radio. And they’re attempting to hear those radio communications while they’re working in hazardous noise and often while they’re using traditional or passive hearing protectors.
During this walkthrough that I mentioned earlier, I also advise to pay attention to the noise, which is how we sort of started out here today. And notice, are there periods of quiet? Do workers remove their hearing protectors during these quiet periods? And if so, do they consistently replace their hearing protection when the noise returns? Because it’s critical that with that fluctuating or intermittent noise that they put the protection back on when they need it. Another assessment method that I suggest is to ask your noise-exposed employees about their audibility needs while they’re working and if their hearing protection may be limiting the things that they need to hear.
Mark Reggers:
That’s some really great advice, Eric, that I think many workplaces and our listeners will get some value from. I mean, adding audibility needs as a hearing-protection selection criteria could increase hearing protection use, factoring those things there. Now, you’ve mentioned your military background. So I want to ask you about your experiences in helping protect the hearing of military personnel who work in these very, very complex acoustical environments.
Eric Fallon:
As you just mentioned, they can be extremely complex and, as you can imagine, extremely noisy as well. Military aircraft can reach levels of 120 decibel sound pressure level and weapon systems that can exceed 180 dB peak pressure. So very, very loud pieces of equipment and weapon systems.
And yet, as I mentioned in my introduction, these military environments can transition from very quiet to extremely noisy instantly. So if you imagine soldiers out on a foot patrol– if you’ve seen a war movie, it’s often a very, very quiet environment– they’re trying to be very quiet. And they rely heavily on their hearing for what we call auditory situational awareness, hearing sounds in their environment. That’s not an environment where hearing protection is needed.
But then, without notice, that environment can become extremely noisy due to impulse noise from their weapon systems being fired, for example. And there’s simply no time to transition from that unfit stage to fitting their hearing protection. So the key in a situation like that is to utilize hearing protectors that make what you want to hear audible and quiet while at the same time, they maintain a protective factor so that those sudden bursts of noise are hopefully reduced to much safer levels.
Laurie Wells:
Now, you’ve described a very critical situation there. And so this is an incredibly important capability. But it sounds a bit magical. Tell us how it works?
Eric Fallon:
Well, it does sound magical, but not quite. So let me start by defining a couple of terms that I think are important to this discussion. The first is level-dependent hearing protection. This term, level-dependent, describes the feature that allows the amount of attenuation you get from a hearing protector or the noise reduction to vary depending on the level of environmental noise. So you can almost think of it as kind of on-demand hearing protection.
The second term that’s important here is a term that I use called environmental listening, being able to hear your surroundings. Some people often refer to this as auditory situational awareness. I may have used that term earlier in describing the military. So level-dependent hearing protection and environmental listening, you have to understand those two terms in order to build upon how these electronic hearing protectors help you.
Mark Reggers:
OK. I think I’ve got it. We have level-dependent and environmental listening, two really important key features here in these kind of environments you’re describing.
Eric Fallon:
That’s right. And so now, if we put those concepts together, your electronic level-dependent hearing protectors utilize microphones that are located somewhere on the body of the hearing protector. And they use an electronic circuitry and speakers to pick up the sound from the environment and then reproduce those sounds from outside the hearing protector and reproduce them on the protected side of the hearing protector.
These products often have some type of volume control so that you can actually make your environmental sounds louder or softer, based on your comfort level. And that way, the user can adjust the incoming sound to a comfortable level for their listening. But what’s important to know about these electronic level-dependent hearing protectors is that regardless of the volume setting, the electronic hearing protector has a sound level limiter that prevents the sound from being reproduced or amplified above some predetermined safe level.
All electronic hearing protectors have, also, some type of nonelectronic component, such as the cushion or an ear tip, if you will, that give that specific protector its attenuation rating. So think of these as products that rely both on an electronic component and then your more traditional passive component to help protect the user’s hearing against hazardous noise.
Mark Reggers:
So you’ve used some really good examples in your military experience. But what about an example for general industry, per se?
Eric Fallon:
Great question. An example I like to use is someone working in a maintenance shop. The shop can be pretty quiet when none of the equipment is running, right? But suddenly, someone turns on a machine and starts cutting metal. And everyone in that shop went from being in a quiet environment to suddenly being in a hazardous noise environment. So, the level-dependent function, together with the environmental listening, allows the workers to hear each other in quiet without needing to remove their hearing protectors but be protected when that saw starts whining because someone was cutting a piece of metal.
Laurie Wells:
Great, Eric. So now I’d like you to add on to that list of terms that you started. And a term that we hear a lot is noise cancellation. So, what does noise cancellation mean? And how does it apply to hearing protectors?
Eric Fallon:
Another really good question. There are a number of different meanings when we speak of noise cancellation. One type of noise cancellation that’s really found its way into the consumer marketplace is called Active Noise Cancellation, or ANC. You’ll also hear it referred to as Active Noise Reduction, or ANR technology. And this involves the electronic circuit picking up that sound with the environmental microphones, as I mentioned earlier, measuring the sound, and then recreating that sound 180 degrees out of phase.
And so what happens is when you combine two sounds and that are out of phase with each other, they cancel each other out. So ANR technology works really well for low-frequency sounds and is commonly used in headphones to improve sound quality. You may have used these on aircraft to help reduce that very low frequency or that low-pitch hum so that you can hear the music or the TV show that you’re streaming a little bit better.
And as I said, this type of noise cancellation works best in the low frequencies. So you may not get much protection against high-frequency sounds. And so you really can’t rely on active noise reduction for hearing protection needs across the spectrum.
As I discussed earlier, traditional passive hearing protection can also be used to reduce noise levels. So imagine a headset that’s designed for communication, The headset is connected to a radio. And the incoming radio transmissions are delivered inside the headset, beyond the passive earmuff cushion or ear tip, into what is now a less noisy ear canal.
So, in that example, it’s the passive cushion that was used to reduce the noise level. So you can have an electronic way of helping reduce the noise, although it’s primarily low frequency, or you can rely on the passive component of the hearing protector to help reduce noise to help improve what you’re trying to listen to as well.
Mark Reggers:
Mentioned earlier, there’s different meanings for noise cancellation. What else comes to mind?
Eric Fallon:
Well, what I’ve talked about so far has been primarily the way that you use noise cancellation for listening. But another use of the term “noise-cancelling” or “noise cancellation” applies to microphone technology. And in this case, I’m speaking about microphones used to transmit out over communication devices.
So, think about a worker standing in a high level of noise. And they’re transmitting over a radio using their communications headset. Ideally, what you want is for that transmission to contain that talker’s message and not all the environmental noise that may be in the background. So, if it’s a communications headset designed for noise, these headsets usually have a boom microphone that comes from the ear cup around to the front of the mouth. It should be positioned very close to the mouth.
And these noise-cancelling boom microphones, they basically have two ports– one that faces the mouth and the other that faces away from the mouth or on the opposite side of the mic. So these two ports, they both send sound. And if sound is striking both ports, both the part facing the mouth and the part facing away from the mouth, it assumes that that’s environmental noise, and it decreases the noise. And the sound that is striking the microphone closest to the mouth, that port, it deems that is what you want to transmit. And so that’s what the person on the other end would hear.
And so these noise cancelling microphones work really, really well. And you can have individuals communicating in high levels of noise. And the person on the receiving end would not know that they’re in noise. I hope that makes sense.
Laurie Wells:
Yes, it does, actually. Yes, perfectly. Perfect description. And I have a really good visual image now in my head about how these noise-cancelling microphones work. And ultimately, I guess you could say that these noise-cancellation microphones provide a way to enhance the signal relative to that background noise that you don’t want to hear.
Eric Fallon:
That’s correct. Yeah. And it’s just part of the story. There are other ways that that signal– and by signal, I really mean the message that you want to transmit to someone across the radio– can be further improved by things like signal processing within the circuitry. That can be another way of helping remove some of the noise. So, some really great technologies out there to assist with the radio communications and high levels of noise that also offer you some type of hearing protection.
Mark Reggers:
Thinking of radios and this protective communication headset, how do they connect to the radios? Because there’s lots of different devices that workplaces need to use or want to use when talking about communication and these devices.
Eric Fallon:
That’s a really great question, Mark. I’ll start by mentioning that I see noise-exposed personnel using work cell phones as well as radios as part of their company’s communication strategy. So, 30 years ago, it was primarily just radios. But now, cell phones have really become very common for people to use as a communication strategy within the high levels of noise.
And as you can imagine with electronic communication headsets, it’s critical to get that incoming signal from the radio or the phone to the headset. And so this can be accomplished by connecting the headset to the device by cable or connecting it through some type of wireless technology, such as Bluetooth. There are too many radio options to go through right now. But in my experiences, I’ve been able to find solutions to help improve workers’ confidence and safety by helping them hear both their environmental sounds as well as the speech communications in many different environmental noise scenarios.
Laurie Wells:
Eric, you have given some information here today, along with some really great practical tips to our listeners, for troubleshooting these complex noise and communication environments. Is there anything else you’d like to add before we close?
Eric Fallon:
Sometimes, these situations of trying to communicate and maintain a degree of hearing and noise are pretty straightforward. But other times, it may take some experimenting to match up the right type of technology to the specific needs of that workplace or that workforce. In most cases, if a worker is struggling with audibility or communications related to the noise they’re working in or they’re currently issued hearing protectors, there’s often a solution available that will help them in that situation.
Mark Reggers:
Well, Eric, I can appreciate this is just the tip of the iceberg with this. There’s so much information here and so much more to learn. But look, thank you so much for bringing this information and potential solutions to our listeners today.
Eric Fallon:
Absolutely, Mark. It’s been my pleasure to be here to talk with you today.
Laurie Wells:
And I will echo Mark’s sentiment. Pardon the pun. But thank you, Eric, for not only information. But I know you’re quite a passionate hearing conservationist. And I appreciate your dedication to helping to protect and preserve hearing.
Eric Fallon:
Oh, thank you, Laurie and Mark. I hope people will realize that there are ways to overcome some of these barriers we’ve talked about today. And I’m happy to be part of the solution.
Mark Reggers:
Well, thanks for listening, everyone. You can listen, subscribe to, and share this podcast through Apple Podcasts, Spotify, Google Podcasts, and most major podcast apps and platforms. If you have any questions, topics, suggestions, or like some assistance in your workplace when it comes to the appropriate selection, use, and maintenance of PPE, you can get in contact with this podcast by contacting your local 3M office or visiting our website, mmm.com.
Around the world, we aim to help everyone get the job done safely today, tomorrow, and in the future. Thanks for listening. And have a safe day. Stay healthy, Laurie.
Laurie Wells:
Stay safe and sound, Mark.
Mark Reggers:
Thanks, everyone. Bye.
Laurie Wells:
Bye-bye.
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