Learn how to resolve the conflict of workers who need to wear hearing protection but still hear speech or warning signals.
Employees at your company need to wear hearing protectors, so you give them the highest level of protection available, right? Not always.
If you believe that one ear plug or muff is pretty much like the next, with the noise-reduction rating (NRR) as the only difference, you may be putting employees at risk if they need to communicate with co-workers or hear warning signals.
Overprotection
In many cases, wearing a hearing protection device (HPD) with too high of an NRR could cause overprotection, which is too much attenuation (decibel reduction in sound power and pressure levels) of a specific noise caused by inadequate hearing protector selection.
There are situations where a particular hearing protector may attenuate high frequencies (speech and signals) substantially more than low frequencies (ambient or background noise). The result is that important consonant sounds of speech may be unintelligible, and warning signals such as backup alarms on forklifts might not be heard.
Communication
Workers with too much hearing protection may not be able to communicate with a co-worker and might remove their HPDs to talk or, if they wear ear plugs, not fully insert the plug into their ear, both of which could cause noise-induced hearing loss.
In industrial settings, low-frequency sounds tend to mask or obscure mid and high-frequency sounds, which leads to decreased speech intelligibility.
Warning signals
As with speech, the ability to hear warning signals, alarms, and machinery operating noise can be diminished when wearing the wrong type of HPD. With machinery noise, for example, the operator needs to be able to hear a signal that would indicate a malfunction.
Solutions
What is the proper type of HPD that allows the wearer to hear necessary speech and signals? The simple answer is a protector that has moderate attenuation of mid- and high-frequency sounds and the proper NRR for the situation. Arriving at a complete answer, however, is not so simple.
The effectiveness of a hearing protector is highly dependent on wearing time. According to EN 458, when someone removes an HPD for even a brief time in the noise exposure, the effective protection provided is significantly reduced.