Ensuring Proper Hearing Protection
August 2009Hearing protection on a job site seems simple: Provide employees with Hearing Protection Devices.
Unfortunately, this approach may be too simple. Unless you have an understanding of how to effectively implement the use of HPDs, you may be creating a more dangerous situation, as well as failing to prevent hearing loss. All employers should implement a hearing conservation program that identifies the level of protection needed, relies first and foremost on engineering and administrative controls to reduce noise and, as a final line of protection, provides HPDs that match the noise level present. This article will focus on the last component, the effective use of HPDs.
The question that must be answered is this: How is it possible for hearing loss to occur when an HPD is in place? There are typically four barriers to the correct use of hearing protection:
• Matching protection level with noise level.
• Consistency of use.
• The ergonomics of use.
• Employee communication needs.
Matching Protection to the Noise Sounds are measured in decibels (dB) for loudness and hertz (Hz) for frequency or pitch. Required and recommended limits of noise exposure are based on an 8-hour time-weighted average of loudness. OSHA requires levels to be below an average of 90 dB for an 8-hour day.
HPDs are given a Noise Reduction Rating. An HPD with a NRR of 29 would theoretically lower noise levels in the workplace by that level. However, testing and real life may yield different results. In addition, the NRR of HPDs actually varies by frequency. Therefore, per OSHA guidelines, the protection rating is calculated by subtracting a factor of 7. For example, an ear plug with an NRR of 29 would lower levels by only 22 dB. To ensure proper protection, consult the manufacturer to select a device that best matches the loudness and frequency levels of the noises you may encounter on the job.
Use HPD Consistently
Another barrier to level of protection is the correct and consistent use of HPD. During an 8-hour day users will remove the device. It is removed for breaks, lunch and may be removed for communication. Typically this amounts to a cumulative period of one hour per day without protection. These short periods of non-use compromise an HPD’s overall protection. An HPD with a NRR of 25 may provide less than 10 decibels of actual protection if they are removed for only one cumulative hour in noisy conditions.
If the HPD isn’t comfortable to wear, it may be removed more frequently or not used at all. The obvious NRR rating of the device is zero if they never make it out of the employees’ pockets.
At present there is no evaluation protocol for the comfort level of HPD. Various types of HPDs should be made available to employees to ensure comfort.
Ergonomics of Use
Ergonomics is also seen as a barrier to proper and consistent HPD use. Quite simply, if an employee is physically unable to insert the HPD correctly, the device is much less likely to protect his hearing.
For example, an ear plug is inserted by reaching around the head pulling on the ear, and with the other hand rolling the foam plug to minimize its size, then inserting it in the ear canal. An HPD that is incorrectly placed in the ear canal doesn’t have the same NRR as when it is inserted correctly. If the insertion process is physically difficult or painful, the employee may not insert it probably or not insert it at all. Manufacturers should be consulted for HPDs that will not present this problem.
The communication need of employees is the final barrier to HPD use. On a job site employees need to be able to hear in order to do their jobs. Critical workplace communication needs include the following:
• Warning signal detection.
• Location of sounds on the site.
• Verbal communication.
Since there is a need on a job site to hear some amount of ambient sounds, there is such a thing as too much hearing protection. The ideal level of protection is between 75 and 80 decibels; too much more (less than 70 decibels) is considered overprotection. Unfortunately, those who are overprotected are more likely to experience hearing loss. Although this may sound illogical, if workers can’t hear verbal commands or warning signals, they will remove their HPD more often to hear these necessities. This increases the overall time during a day that the ears are unprotected, leading to a greater likelihood of hearing loss over time.
To decrease the amount of hearing loss at job sites it is necessary to overcome these barriers. It is crucial that when choosing hearing protection for your employees that more time and energy is spent on figuring out the specific needs of the employees for the HPD.
New testing methods are being developed that will help employers match the level of protection with the amount of protection needed. These methods will help to decrease the difference between the theoretical protection of the HPD and the actual amount of protection provided. Individual fit testing for each employee will help to settle the comfort and ergonomic issues as well.
By working with individual employees on the fit and comfort of the HPD, the employee will be more satisfied with the device and will therefore be more likely to use the HPD at all times on the job site. If employers choose HPDs that have sufficient protection and are flat attenuated (meaning that they provide an equal reduction in sound across frequency), employees will have the hearing protection they need but still be able to hear the ambient sounds necessary to safely complete their on-the-job tasks each day.
Diane Kelly is a safety specialist with INTEC, Waverly, Pa.