How to Choose HPDs to Avoid Overprotection
August 12, 2019
Driven by stringent industrial regulations, the US industrial hearing protection market is expected to surpass $650 million by 2024, reports say.
This means hundreds of new earmuffs and earplug models will flood the market, making the quest for the perfect hearing protection PPE even more difficult. Especially since workers complain that HPDs are plain uncomfortable or interfere with other protective equipment like hard hats, face shields and respirators.
So, what is the best hearing protection for workers? Honeywell’s hearing experts unanimously agree that hearing protection safety should provide optimal protection, proper fit and comfort, and, most of all, be worn at all times when exposed to exceeding noise levels.
More specifically, here is what you need to consider when choosing the right hearing protection tools for your workers and working environment.
Noise level measurement
To determine the level of hearing protection, you need to first accurately measure the level of noise inside your facility. This helps determine the level of attenuation required to adhere to current OSHA regulations.
Currently, OSHA’s noise standard (29 CFR 1910.95) requires employees to implement a hearing conservation program if workers are exposed to time-weighted average noise level of 85 decibels over an 8-hour shift.
Most manufacturers have created charts showing protection levels for their products. In the US, HPDs carry a label with a noise reduction rating (NRR) level that indicates the level of hearing protection. The NRR is calculated by subtracting the 85db from the noise level. For instance, chainsaw noise is 110db. To go from 110db to below 85db you need an earmuff with an attenuation of at least 25db. Hearing protection ratings can increase to a maximum of 33 for earplugs and 31 for earmuffs.
Is there an HPD that blocks sound 100%?
Yes, but is that safe? A worker who can’t hear the warning signal of a truck or piece of heavy equipment coming his way may be in danger. Workers who can’t hear and thus, cannot communicate effectively with peers are also more likely to make mistakes and tend to feel more isolated on the job.
Overprotection is a very real problem. So, simply going for the HPD with the highest NRR is not an option.
Comfort and fit
Is there anything more stressing than an earmuff that presses your head? Comfort and fit are tied together and play a significant role in determining workers to wear PPE. That is why Investing in an ear-plug fit testing system is well-worth it. Fit-testing provides a real-world metric that help managers understand if employees are receiving optimal protection for the noise environment they work in.
VeriPRO determines the Personal Attenuation Rating (PAR) of the earplugs each employee uses regularly on the job and can help managers determine whether employees require additional fit training or different style earplugs.
Compatibility with other PPE
When on duty, workers combine a variety of protective equipment to keep them safe – safety eyewear, clothing, shoes, gloves. Thus, selecting PPE that does not compromise the operation or efficiency of another PPE is quite important.
For instance, safety eyewear with thick frames (6mm) can cause a gap between the head and the earmuffs, providing an easy way for sound to penetrate the earcup, and thus, reducing optimal attenuation by 2 decibels. Other factors that contribute to creating this gap are:
- band pressure of the earmuff, heap shape and head size
- compliance of the ear cushion material (stiff material is prone to gaps)
- thickness of the eyewear frames
- compliance of the eyewear frames
An internal Howard Leight Acoustical Lab study showed that wearing safety eyewear with thin frames (less than 2mm), does not signify a decline in attenuation. The NRR is reduced by about 2db when worn with a medium-width frame (3mm) and by about 5db when worn with a thick frame (6mm).
When it comes to hard hats or helmets, it’s best to use cap-mounted earmuffs that slot onto hard hats.
For respirators, any style will work. Ultra slim neckband earmuffs allow good clearance between the earcup and the hood.
In certain industries, such food and beverages production, contamination with foreign objects is a big problem. As such, hearing protection needs to be easy to detect through visual detection equipment and thermal imaging cameras and sensors. One solution is to choose earplugs with attached cords to keep them from falling off, in the first place. The second is to wear detectable safety earplugs in contrasting colors to help with the visual inspection. Lastly, you can opt for earplugs that include fixed metal grommets that can be easily identified by metal-detecting sensors.
Oftentimes, people working with electricity, utilities or in mining operations are forbidden to wear PPE with metal elements. Metal conducts electricity, exposing workers to electrical hazards. To mitigate this risk, workers should opt for single-use, multiple-use, banded earplugs or dielectric earmuffs.
New hearing technologies
Do workers need hearing protection with bluetooth and radio to communicate or simply listen to music?
Studies show that ear protection with integrated stereo sound can make workers more productive and motivated on the job. Hence, new sound technologies embedded in connected earmuffs amplify important bass sounds such as alarms and warning signals from co-workers, while reducing unwanted dangerous noise.
Can too much sound kill you? It is speculated that 195 decibels (the sound made by a rocket launch) is enough loudness to permanently damage lungs. The largest European testing facility of its kind, LEAF, can produce up to 154 decibels of noise, through four sound horns, subjecting satellites to the same noise a launcher produces as it takes off and flies through the atmosphere.