Hearing protection on a job site seems simple. Provide employees with hearing protection devices (HPDs). Unfortunately, this approach may be too simple. Unless you know 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 on engineering and administrative controls to reduce noise, and, as a final line of protection, provides HPDs that match the noise level present.
The question that must be answered is “how is it possible for hearing loss to occur when an HPD is in place?” Typically, there are four barriers to the correct use of hearing protection: matching protection level with noise level, consistency of use, the ergonomics of use, and employee communication needs. 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 eight-hour, time-weighted average of loudness. The Occupational Safety and Health Administration (OSHA) requires levels to be below an average of 90 dB for an eight-hour day. HPDs are given a noise-reduction rating (NRR). An HPD with a NRR of 29 would theoretically lower noise levels in the workplace by that level. However, testing and real situations 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 seven. For example, an earplug 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.
Another barrier to level of protection is the correct and consistent use of HPDs. During an eight-hour day, users will periodically remove the devices for breaks and lunch and possibly even for communication. Typically, this amounts to a cumulative period of one hour per day without protection.
These short periods of nonuse compromise the overall protection of HPDs. An HPD with a NRR of 25 may provide less than 10 dB of actual protection if they are removed for only one cumulative hour in noisy conditions.
Ergonomic design also is seen as a barrier to proper and consistent HPD use. If the HPD isn’t comfortable to wear, it may be removed more frequently or not worn at all. The obvious NRR rating of HPDs is zero if they never make it out of the employees’ pockets. Currently, there is no evaluation protocol for the comfort level of HPD. Various types of HPDs should be made available to employees to ensure they are comfortable.
Also, if an employee is physically unable to insert the HPD correctly, the device is much less likely to protect their hearing. For example, an earplug is inserted by reaching around the head and pulling on the ear with one hand, while the other hand rolls the foam plug to minimize its size, then places it in the ear canal. An incorretly placed HPD 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 properly or will not insert it at all. Manufacturers should be consulted for HPDs that will not present this problem.
The employees’ communication need is the final barrier to HPD use. On a job site, employees need to be able to hear to do their jobs. Critical workplace communication needs include the following:
• Warning signal detection
• Location of sounds on the site
• Verbal communication
The ideal level of protection is 75–80 dB. Much more is considered overprotection. Unfortunately, overprotection can lead to hearing loss. This may sound illogical, but if workers can’t hear verbal commands or warning signals, they will remove their HPDs 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. When choosing hearing protection for your employees, it is crucial to figure out the employees’ specific HPDs needs. The new testing methods that are being developed will help employers match the level of protection with the amount needed. These methods will help to decrease the difference between the theoretical protection of the HPD and the actual amount of protection provided. 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, employees will have the hearing protection they need, but will still be able to hear the ambient sounds necessary to safely complete their on-the-job tasks each day.
KELLY is a safety and health specialist with Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. She can be reached at 800.745.4818 and firstname.lastname@example.org. Joe O’Connor edited this article.