When Employees Need Protection
The Action Level
A workplace must have a hearing conservation program when employees are exposed to noise levels equal to or greater than 85 decibels (dBA), averaged over an eight-hour workday. This 85 dBA level is called the "action level." It represents the average noise exposure during a work shift, based on both the intensity of the noise and the duration of exposure.
Measure Noise Levels: Use a sound level meter to measure the noise level (in decibels, dB) at various times and locations within the employee's work environment.
Determine Exposure Times: Document the duration of time the employee is exposed to each level of noise. This should be performed for every distinct noise level encountered throughout the employee's workday.
Calculate the TWA: The TWA is calculated using the following formula:
Interpret the Result: Compare the TWA to relevant occupational noise exposure limits set by regulatory bodies such as OSHA. If the TWA exceeds these limits, it indicates that the noise exposure is excessive, and steps should be taken to reduce the noise level or the duration of exposure.
The Permissible Exposure Limit (PEL)
The action level is different from the Permissible Exposure Limit (PEL). The PEL is 90 dBA for an 8-hour TWA. If noise levels exceed the PEL, employers must use engineering or administrative controls to reduce exposure. If these controls are not enough, employees must also use hearing protection devices to reduce noise exposure to a safe level.
Maximum Permissible Noise Exposures*
| Duration Per Day | Maximum Exposure Level (dB) |
|---|---|
| 8 | 90 |
| 6 | 92 |
| 4 | 95 |
| 3 | 97 |
| 2 | 100 |
| 1 1/2 | 102 |
| 1 | 105 |
| 1/2 | 110 |
| 1/4 or less | 115 |
*Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level.
Knowledge Check Choose the best answer for the question.
7-5. What is the "action level" that requires the employer to establish a Hearing Conservation Program?
You forgot to answer the question!