Table A.13: SPL Examples and Hearing Protection
| SPL (dB) | Example | Hearing Damage Risk | Exposure Time Limit | Protection Needed |
|---|---|---|---|---|
| 0 | Threshold of hearing | None | Unlimited | None |
| 30 | Whisper, quiet library | None | Unlimited | None |
| 60 | Normal conversation | None | Unlimited | None |
| 70 | Busy traffic, vacuum cleaner | None | Unlimited | None |
| 85 | Heavy city traffic, blender | Risk begins | 8 hours | Consider for extended exposure |
| 90 | Lawn mower, shop tools | Moderate risk | 2.5 hours | Recommended |
| 95 | Motorcycle, power tools | High risk | 47 minutes | Strongly recommended |
| 100 | Chainsaw, snowmobile | High risk | 15 minutes | Required |
| 105 | Personal stereo at max | Very high risk | 4 minutes | Required |
| 110 | Rock concert, car horn | Very high risk | 90 seconds | Required |
| 115 | Loud rock concert | Extreme risk | 28 seconds | Required - double protection |
| 120 | Thunder, pneumatic drill | Extreme risk | 9 seconds | Required - double protection |
| 130 | Jackhammer, loud car audio | Immediate damage | < 1 second | Required - double protection |
| 140 | Jet engine, gunshot | Immediate damage | Instant | Required - double protection |
| 150 | SPL competition | Immediate severe damage | Instant | Required - double protection |
| 160 | Top SPL competition | Immediate severe damage | Instant | Required - double protection |
Hearing Protection NRR Ratings: - Foam earplugs: NRR 28-33 dB - Reusable earplugs: NRR 20-27 dB - Earmuffs: NRR 22-31 dB - Double protection (plugs + muffs): Effective NRR 35-40 dB