The limits
NIOSH recommends a maximum of 85 dBA for 8 hours, halving the time for every 3 dB increase (88 dBA → 4 h, 91 dBA → 2 h, 100 dBA → 15 minutes).
OSHA's legal limit in US workplaces is 90 dBA for 8 hours with a 5 dB exchange rate, which allows more exposure. Hearing-conservation programmes start at 85 dBA.
Frequently asked questions
What is a noise dose?
The percentage of the daily allowable exposure you have used. 100% means you have reached the limit.
Is this medical advice?
No – it is general information based on occupational guidelines.