PPE Management: What Supervisors Need to Know About Fitting Earplugs
There are many ways workers learn how to wear earplugs - in safety briefings, group training sessions or in an introduction to a job site. Too often, the person providing hearing protector training is little more than a dispenser, handing the worker earplugs and saying, “Here, use these around loud noise” or “Stick these in your ears.” How loud is too loud? Simply put, the risk of damage to hearing is calculated on the basis of how loud and for how long. Experts agree that continued exposure to noise at or above 85 dB(A) over time can cause a hearing loss. You’ve been listening too loudly or for too long if you have ringing in your ears or dull hearing after listening to loud music. However, you may still be damaging your hearing even if you don’t have these symptoms. Without noise measuring equipment, it will be impossible for you to tell what noise level you are being exposed to. So, a handy rule of thumb is that if you can’t talk to someone 2 metres away without shouting, the noise level could be damaging. Workers need to know not only when and why they should use earplugs, but how to use them effectively.
Figure 1: Attenuation acheived by a good fit versus a poor fit of a foam earplug in a worker's ear. A poor acoustic seal causes no attenuation of hazardous low-frequency noise and little attenuation in high frequencies. Training any new skill - whether it's how to use a tool or how to be safe on the job - can be done by presentation or lecture, hands-on training, small group training, consulting from a distance, informal training or one-on-one training.
Achieving good earplug fit is not always easy, and there are several points trainers need to understand in order to use that one-on-one training time well. First, there are three steps to fitting an earplug: 1) preparing the earplug (for roll-down or foam plugs); 2) opening the ear canal; and 3) inserting the earplug. Let's look at each of these steps individually. PREPARE THE EARPLUG No-roll foam and multiple-use earplugs do not require much preparation, but a very critical part of getting adequate protection with foam earplugs is the roll-down. With clean hands, roll the entire earplug into the narrowest possible crease-free cylinder. Most instructions show rolling with the fingers of one hand, but I like to use two hands for a really tight cylinder. When rolled down well, the earplug should be a little longer and noticeably stiffer. This allows the earplug to work its way around the first bend of the ear canal. Once the earplug is rolled very tightly, whether you use two hands or one, move it quickly to the ear canal for placement. OPEN THE EAR CANAL For all types of earplugs, the more open the ear canal, the easier it is to insert the earplug and achieve a proper fit. To open the ear canal, simply reach over your head and pull on the top
of your ear. Usually, pulling up and back opens the canal best. However some ear canals open more fully by pulling out on the ear. There are a couple of methods to help users learn the best way to pull their ear open in oneon-one training. One is to look at the person's ear canal (be sure to look at both ears as they may be different) and give them feedback as to when the canal is most open. Another way is to take a picture of their ear canal at rest and then again as they reach over and open their canal. Many phones have cameras so it's easy to get a digital photograph and then just delete it. INSERT THE EARPLUG The earplug must be inserted well inside the ear canal to be effective. Once a roll-down foam earplug is prepared, quick insertion is a key to getting adequate attenuation. Stopping to admire the great job you've done with the roll-down is not a good idea! Opening the ear canal properly makes insertion of the earplug much easier. A properly rolled foam earplug should basically lie on the ear canal floor and expand to seal the entire canal. Whether using single-use or multiple-use earplugs, a little movement or wiggle often is required to place the earplug in the correct location, well inside the ear canal. Earplugs that are placed too near the entry to the ear canal are not as effective and can cause what's known as the Occlusion Effect. The Occlusion Effect is the amplification of bodyborne sounds caused when you occlude or close off the ear canal. With hearing protectors, the Occlusion Effect is reduced by inserting the earplug deeper into the ear canal, or by stiffening the soft portion of the ear canal by using an earplug with more surface contact in the ear canal.
CHECKING THE FIT There are several ways of verifying whether the earplug is properly fitted: Visual Check — For earplugs with a stem (a firm protruding piece intended to be grasped by the user for insertion), only the tip of the stem should be visible to someone looking at you from the front, or when you view yourself in a mirror. All flanges of a flanged-earplug should be well inside the ear canal. For earplugs without stems, the ends of the earplugs should not be visible to someone looking at you from the front. An earplug that clearly is visible from the front is a warning sign of poor insertion. Acoustic Check — A hearing protector only is useful when it achieves an acoustic seal in the ear canal. An acoustic seal causes a very pronounced lowering of noise levels. Here is one way of checking the acoustic seal of an earplug. With earplugs inserted, cup your hands firmly over the ears and release. The earplugs should be blocking enough noise so that covering the ears with your hands results in no significant change in noise level.
Subjective Fit Testing — Several new tools now allow accurate measurement of real-world attenuation, so that workers (and employers) can verify the protection offered by earplugs. One such system uses a method in which a probe microphone is inserted into specially modified earplugs. Users don these test earplugs and listen while a loud noise sample is played. Software then calculates how much noise is blocked by the earplug. Another system administers a short listening test to the users, both with/without earplugs inserted, and calculates real-world attenuation from the difference in the two tests. This system can be used with any earplug model (no modification required).
General rules for any type of earplug
Inspect the earplug prior to use - look for any cracks, tears or imperfections. To insert - reach one hand behind your head and pull your ear outward and upward to straighten the ear canal. Sometimes it helps to open your mouth while you insert the earplug. When the earplug is in your ear properly, only a small portion should be visible. You should always be able to grab the end with your fingers to rotate it and gently remove it.
To protect your hearing, earplugs must provide enough attenuation (measured in decibels).
Sound is made up of different frequenices, and most earplugs will attenuate at a different level for each of those frequencies. These levels vary between manufacturers, so you should check the packaging to see what protection they give. Most earplugs give greater protection at higher frequencies (4 to 8 kilohertz) than at lower frequencies, and it is these higher frequency sounds that are potentially more damaging to hearing. Remember that in real situations the attenuation is probably less than that measured by the manufacturers, as they will have tested brand new earplugs that fit well, and the tests will have been done in ideal circumstances. Attenuation is sometimes expressed as a single simplified noise-level reduction (SNR) figure.
Q: How long does it take to get used to hearing protectors? A: Think about getting a new pair of shoes. Some shoes take no time to get used to. Others - even though they are the right size - can take a while to get used to. Hearing protectors are no different from other safety equipment in terms of getting used to them. However, if hearing protectors are the wrong size, or are worn out, they will not be comfortable. In addition, workers may need more than one kind of protector at their job. For example, no one would wear golf shoes to go bowling. If hearing protectors are not suitable for the work being done, they probably will not feel comfortable. Q: How often should your hearing be tested? A: Anyone regularly exposed to hazardous noise should have an annual hearing test. In addition, anyone who notices a change in his/her hearing (or who develops tinnitus) should have his or her ears checked. People who have healthy ears and who are not exposed to hazardous noise should get a hearing test every three years. Everybody’s hearing can be damaged by loud noises and nobody can harden their ears against that damage. Some people are more susceptible to noise damage than others, but you probably won’t know how susceptible you are until you have damaged your hearing. Noise induced hearing loss is usually painless and gradual, which often makes it difficult to notice that it is there until it is too late. Once it happens it is permanent. When you damage the hair cells in your ear they die and cannot be repaired.