Deciphering OSHA Noise Regulations

Deciphering OSHA Noise Regulations and understanding what the regulations mean to your business, your neighbors, and your workforce is an important step in being a good corporate citizen.

Every year, approximately 30 million people in the United States are exposed to hazardous noise in the workplace which may result in temporary or permanent hearing loss, create physical and psychological stress, reduce productivity, interfere with communication and concentration, and contribute to workplace accidents and injuries by making it difficult to hear warning signals.  The US Occupational Safety and Health Administration (OSHA) regulates workplace noise by requiring companies to limit the exposure of their workers to high noise levels. We would like to help you by deciphering OSHA noise regulations.

OSHA requires an employer to administer a hearing conservation program whenever employees are exposed to noise levels that are at or above an eight-hour time-weighted average (TWA) of 85 dBA (the so-called “Action Level”) or, equivalently, a dose of 50 percent of the maximum permissible level of 90 dBA.  Minimum requirements of a hearing conservation program include (a) a monitoring program, (b) an audiometric testing program, (c) hearing protection devices, (d) employee training and education, and (e) recordkeeping. HUH?????? Now you see why we want to help with deciphering OSHA noise regulations.

Companies that implement hearing conservation programs spend about $350 to $400 per program participant per year, where the highest program cost for companies surveyed was $1,800 per participant per year.  Workers’ Compensation costs for hearing loss were also found to average about 0.2% of payroll.

OSHA calculates worker noise exposure based on a time weighted average (TWA) that is calculated using noise levels to which a worker is exposed during normal working hours.  The OSHA permissible exposure limit (PEL) is 90 dBA over an 8-hour period, and the equivalent exposure times at different SPLs is given by the equation,

Equation 1where L is the measured A-weighted sound pressure level.   So (for example), OSHA will allow 4 hours of exposure at 95 dBA and 2 hours of exposure at 100 dBA.  A worker’s dosage is determined by calculating the sum of the product of his time spent at certain noise levels (Cn) multiplied by the equivalent allowable time at these noise levels:

Equation 2Once the dose is obtained, the TWA is calculated by the following equation:

Equation 3

For example, if a worker is servicing machines that emit noise of 100 dB four hours per day, and is exposed to noise in other areas of the facility of 90 dB for three hours per day, and background noise of 80 dB when no machinery is operating for one hour per day,

Dose = [(4/2.0) + (3/8.0) + (1/32.0)] = 2.41

TWA = 16.61 * log10[1.36] + 90 = 96.3 dBA

In this example, the TWA exceeds the OSHA action level of 85 dBA, requiring an employer-sponsored hearing conservation program.  In fact, in order to fall below the 85 dBA TWA action level, the dose will need to be 0.5 or less.

Sonic-Shield can assist your company by performing tests and analyses to determine compliance with OSHA noise guidelines and implementing effective soundproofing to reduce exposure of your employees to high noise levels.  In some cases, it may be possible to reduce noise levels sufficiently to eliminate OSHA requirements for a hearing conservation program, improving productivity, ensuring employee health and wellness, and resulting in significant savings.

Deciphering OSHA noise regulations can also be accomplished more simply by reading the following chart. You do not have to be an expert in algebra and formulas when it comes to deciphering OSHA noise regulations. Simply look at the chart below and talk to us about how to take readings for your business to understand if you are in compliance.

Deciphering OSHA Noise Regulations
U.S.-Occupational Regulations for Noise Acoustics



Deciphering OSHA Noise Regulations