Under the U.S. Occupational Safety and Health Administration general standard regulations, the permissible exposure limit for workplace noise is 90 decibels as a time-weighted average, or dBA, for an eight-hour work shift, according to the agency. OSHA also calls the limit a 100-percent dose of noise exposure. The OSHA exchange rate is 5 decibels, or dB, meaning an 85 dBA exposure equals a 50-percent dose. A 95 dBA exposure equals a 200-percent dose under the exchange rate.
As of 2015, the federal agency regulations state that the maximum exposure limit for continuous noise is 115 dBA for 15 minutes daily, states OSHA. Employers must implement administrative or engineering controls in the workplace when workers are exposed to sound levels of 90 dBA or higher. Companies must provide their employees with personal protective equipment and ensure that they use it when the controls do not lower the sound levels below 90 dBA. Replacing components and installing acoustical enclosures are among the engineering controls that OSHA accepts. Limiting worker exposure to the noise environment and rotating shifts are examples of OSHA-approved administrative controls.
Employers must administer effective hearing conservation programs on an ongoing basis when workers are exposed to a 50-percent dose of noise exposure, or 85 dBA or more, which is called the action level, explains OSHA. The purposes of the programs are to stop loss of hearing, lower worker stress and boost worker morale and productivity. Regulations require employers to monitor all types of noise levels between 80 and 130 dBA.