The basics are that a 100 decibels for more than 15 minutes can cause hearing loss. At 140 dBA noise causes immediate injury to almost any unprotected ear. A Jet Engine is 140 dB, thunder is about 119 db, and lawnmower is about 90dB.
An AR-15 or AK-47 is ≈155-165 dB. Suppressed ≈ 130-136 dB so loosely as loud as a Jet Engine.
Facts on noise levels
- Decibels measure sound pressure and are logarithmic. That means that only a 3db increase almost doubles sound pressure, a 6db increase quadruples sound pressure, etc.
- Gradual hearing loss may occur after prolonged exposure to 90 decibels or above.
- Exposure to 100 decibels for more than 15 minutes can cause hearing loss.
- Exposure to 110 decibels for more than a minute can cause permanent hearing loss.
- At 140 dBA noise causes immediate injury to almost any unprotected ear.
- There is also the more extreme ‘acoustic trauma’, which is an immediate loss of hearing after a sudden, exceptionally loud noise such as an explosion.
- Properly fitted earplugs or muffs reduce noise 15 to 30 dB each
- earplugs are better for low frequency noise, earmuffs are better for high frequency noise
- Combined, about 35 dB
Comparative noise levels and length of time for damage to occur
- Jet engine taking off 140 dB Instant damage
- Thunder/Ambulance siren 119 dB 3 minutes
- Hammer drill 113 dB 15 minutes
- Chain saw/Earphones/Concert 110 dB 30 minutes
- Bull Dozer 105 dB 1 hour
- Tractor/Power tools 96 dB 4 hour
- Hairdryer/lawnmower 90 dB 8 hours
Noise levels of Pistols
- .380 157.7 dB.
- 9mm 159.8 dB.
- .38 Spl 156.3 dB.
- .357 Magnum 164.3 dB.
- .45 ACP 157.0 dB.
Noise levels of Rifles
- .22 caliber rifle 130dB
- .223 (AR-15) ≈ 155.5dB
- .308 / 7.62mm (AK-47) ≈ 156.2dB.
Noise levels of Shotguns
- .410 Bore 28" barrel 150dB. 26" barrel 150.25dB. 18" barrel 156.30dB.
- 20 Gauge 28" barrel 152.50dB. 22" barrel 154.75dB.
- 12 Gauge 28" barrel 151.50dB. 26" barrel 156.10dB. 18" barrel 161.50dB.