What is 8-Hour Time-Weighted Average?

Average noise exposure figured for an 8-hour period.

What is Permissible Exposure Level (PEL)?

Maximum allowable 8-hour TWA noise exposure (OSHA's limit is 90 dBA).

Percent of PEL to which worker exposed. 90 dBA 8-hour TWA equals a dose of 100%. An 85 dBA 8-hour TWA equals 50%. The exchange rate is used to figure this.

What is Exchange Rate?

Amount of dBA at which noise dose doubles. OSHA uses a 5 dBA exchange rate which means that a worker exposed to 95 dBA receives twice the dose of 90 dBA.

What are Noise dosimeters?

Devices used in sound surveys to calculate noise exposure.

Noise Dose Calculator

How To Use the Calculator

Simply enter a Noise Dose value to determine that 8-hour Time-Weighted Average (TWA)

Want to convert noise exposures into a time-weighted average?

Try our TWA Calculator

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Key Definitions

8-Hour Time-Weighted Average: Average noise exposure figured for an 8-hour period.
Permissible Exposure Level (PEL): Maximum allowable 8-hour TWA noise exposure (OSHA's limit is 90 dBA).
Noise Dose: Percent of PEL to which worker exposed. 90 dBA 8-hour TWA equals a dose of 100%. An 85 dBA 8-hour TWA equals 50%. The exchange rate is used to figure this.
Exchange Rate: Amount of dBA at which noise dose doubles. OSHA uses a 5 dBA exchange rate which means that a worker exposed to 95 dBA receives twice the dose of 90 dBA.
Noise dosimeters: Devices used in sound surveys to calculate noise exposure.