At 85 dB you’ll have hearing damage from long term exposure without hearing protection. Normally considered 8 hours a day 5 days a week. So 2000 hours in a year. Higher sound levels have a lower threshold so shorter times. 120 dB is the threshold of pain, so immediate hearing damage. Also, dB are a 10x log scale. So every 10 dB is an order of magnitude increase. So the siren is actually about 3000x louder than when you should start wearing earpro.
At 85 dB you’ll have hearing damage from long term exposure without hearing protection. Normally considered 8 hours a day 5 days a week. So 2000 hours in a year. Higher sound levels have a lower threshold so shorter times. 120 dB is the threshold of pain, so immediate hearing damage. Also, dB are a 10x log scale. So every 10 dB is an order of magnitude increase. So the siren is actually about 3000x louder than when you should start wearing earpro.