Hearing protection device
[1] The use of the HPD without individual selection, training and fit testing[2] does not significantly reduce the risk of hearing loss.
But in practice, the Compliance Safety and Health Officer must record the excess of these values with a margin, in order to take into account the potential measurement error.
[17] The shooting of firearms can cause damage to a variety of cochlear structures due to the high peak sound pressure levels that they generate.
It is important for the consumer to know that this is only a single number estimate derived from a laboratory experiment, and the NRR will vary per individual wearing the hearing protection.
NIOSH and OSHA have derating values to help give the person an idea of how much sound is being attenuated while wearing the hearing protection.
[23] Earmuff style hearing protection devices are designed to fit over the outer ear, or pinna.
Some HPDs reduce the sound reaching the eardrum through a combination of electronic and structural components.
This type may be beneficial for users who are in noisy environments, but still need access to lower level sounds.
This type of hearing protection is particularly recommended for workers in the mining industry because they are exposed to extremely high noise levels, such as an 105 dBA TWA.
[31] In order to prevent irritation or infection of the ear, reusable HPDs should be cleaned on a regular basis.
[32] Earmuff cups and cushions should be cleaned regularly with soap and water, and be replaced if they become cracked or otherwise compromised.
It is also recommended by the U.S. National Institute for Occupational Safety and Health, audiologists and other hearing healthcare professionals when one works exposed to noise levels that exceed 85 dB.
[1] NIOSH base their recommendations for use of hearing protection by a calculation called time-weighted average (TWA).
NIOSH recommends that OSHA use an 85 dBA time-weighted average during an 8-hour period as their exposure limit.
The amount of protection from noise can vary based on the physical fit of the device and the skill of the worker.
[1] There are many challenges to achieving the needed protection from the device, from barriers to adequate use, to issues related to comfort, convenience, lack of training, to beliefs and attitudes towards its use.
[36][37][38][39][40][41] Hearing protection device manufacturers in the United States are required by the EPA to label HPDs with a noise reduction rating, or NRR.
[1] The NRR is measured by manufacturers using American National Standards Institute (ANSI) specified procedures in a laboratory environment.
There were no technical means to take into account the variability of the HPD noise attenuation in different workers for a long time.
The advent of new technologies has solved the problem, and individual measurement of noise attenuation is considered the most promising trend in personal noise protection[47][21] Hearing protection fit-testing has been developed in order to determine the actual attenuation of the device as it is worn for an individual.
[1] The PAR is unique to the HPD tested and the individual wearing the protection, and personal fit testing US OSHA and the National Hearing Conservation Association (NHCA) Alliance recommend that employers conduct individual worker noise attenuation measurements (HPD fit-testing) as a best practice and valuable tool for improving employee training.
NIOSH has tried to alleviate the problem by developing a freely available program (online) for evaluating noise attenuation with liners.
NIOSH fully took into account the significant difference between the real and laboratory effectiveness of personal protective equipment,[55] but other organizations began to recommend similar methods, and they were fixed in state and international standards.
