When must I provide hearing protection for my employees?
Determining the need to provide hearing protection can be tricky. Employee exposure to excessive noise depends upon a number of factors:
Generally, the louder the noise, the shorter the exposure time before you must provide hearing protection. For instance, employees may be exposed to a noise level of 90 dBA for 8 hours per day before you must provide hearing protection for them. Suppose, however, that the noise level reaches 115 dBA in your workplace. Then you must provide hearing protection if their anticipated exposure exceeds 15 minutes.
Table 5 shows when you must provide hearing protection to employees exposed to occupational noise at specific levels for specific periods. Noises are considered continuous if the interval between occurrences of the maximum noise level is 1 second or less. Noises not meeting this definition are considered impact or impulse noises. Exposure to impact or impulse noises (loud momentary explosions of sound) must not exceed 140 dB. Examples of impact or impulse noises may include the noise from a powder-actuated nail gun, the noise from a punch press, or the noise from drop hammers.
For more information on noise, consult Chapter II:5, "Noise Measurement," of the OSHA Technical Manual.(10)
Will earplugs reduce employee exposure to high noise levels?
As with other types of hazards, you must implement feasible engineering controls and work practices before resorting to PPE such as earplugs or earmuffs. If engineering and work practice controls do not lower employee exposure to workplace noise to acceptable levels, then you must provide employees with appropriate PPE.
What if my employees are exposed to different levels of noise throughout the day?
If employees move from location to location and the noise level is different in each location, or if the noise levels in an area change throughout the day (e.g., equipment turns on or off), you must calculate an "equivalent noise factor" to determine whether you must provide hearing protection.
The formula for calculating this exposure is as follows:
What kinds of devices protect against high noise levels? Is cotton sufficient as earplugs?
Plain. cotton does not effectively protect against occupational noise. You may, however, choose from several products that are effective at protecting your employees' hearing.
If I provide my employees with hearing protection, can they then work in areas with any level of noise for any period of time?
No. Hearing protectors reduce only the amount of noise that gets through to the ears. The amount of this reduction is referred to as attenuation. Attenuation differs according to the type of hearing protection used and how well they fit. The hearing protectors you choose must be capable of achieving the attenuation needed to reduce the employee's noise exposure to within the acceptable limits noted in Table 5. Appendix B of 29 CFR 1910.95, Occupational Noise Exposure, describes methods for estimating the attenuation of a particular hearing protector based on the device's noise reduction rating (NRR). Manufacturers of hearing protection devices must report the device's NRRs on the product packaging.
Once I have selected equipment to protect my employees' hearing, how do I make sure they use it properly?
Train your employees to use the hearing protection. Checklist H will help you train your employees to use and care for the earplugs or earmuffs that you provide.
Once I have provided my employees with hearing protection and training in how to use it, how do I know that it is really protecting their hearing?
If your employees are exposed to occupational noise at or above 85 dBA averaged over an 8-hour period, then you must institute a hearing conservation program that includes regular testing of employees' hearing by qualified professionals. The OSHA occupational noise standard, at 29 CFR 1910.95, sets forth the requirements for a hearing conservation program.