Calculate sound levels in decibels, determine hearing protection requirements, and check OSHA exposure limits. Includes decibel comparison chart, safe exposure times, and tool noise ratings.
Configure your shop environment, noise sources, and hearing protection to calculate comprehensive noise level analysis and safety compliance recommendations.
Sound is measured in decibels (dB) on a logarithmic scale. Every 10 dB increase is perceived as twice as loud. OSHA sets 90 dBA as the 8-hour permissible exposure limit (PEL) and 85 dBA as the action level requiring a hearing conservation program.
TWA = 16.61 x log10(D/100) + 90 | Tool/Equipment | Noise Level (dBA) | Max Safe Exposure (OSHA) | Protection Recommended |
|---|---|---|---|
| Hand Tools | 60-70 | Unlimited | None required |
| Dust Collector | 80-90 | 8 hours | Optional (>85 dBA) |
| Table Saw | 85-95 | 4-8 hours | Recommended |
| Planer/Jointer | 90-100 | 2-4 hours | Required |
| Router | 95-105 | 1-2 hours | Required |
| Circular Saw | 100-110 | 15-60 min | Required (dual recommended) |
| Sound Level (dBA) | Max Duration/Day (OSHA) | Max Duration/Day (NIOSH) | Action |
|---|---|---|---|
| 85 | 16 hours | 8 hours | Action level - hearing conservation |
| 90 | 8 hours | 2.5 hours | PEL - protection required |
| 95 | 4 hours | 47 min | Engineering controls needed |
| 100 | 2 hours | 15 min | Dual protection recommended |
| 105 | 1 hour | 5 min | Limit exposure strictly |
| 110 | 30 min | 1.5 min | Avoid if possible |
Logarithmic unit measuring sound intensity. dBA is A-weighted to match human hearing sensitivity. Every 3 dB doubles sound energy; every 10 dB is perceived as twice as loud.
Average noise exposure calculated over an 8-hour workday. TWA of 85 dBA triggers OSHA action level; 90 dBA is the permissible exposure limit.
Lab-tested attenuation in dB provided by hearing protection. Effective NRR is derated - OSHA uses (NRR-7)/2 for real-world estimation.
Cumulative noise exposure as percentage of allowable daily exposure. 100% dose = PEL (90 dBA for 8 hours). Calculated as sum of (actual time / allowable time) for each noise level.
Decibel increase that doubles allowable exposure time. OSHA uses 5 dB (halving time every 5 dB). NIOSH uses 3 dB (more conservative). Also called doubling rate.
OSHA sets permissible exposure limit (PEL) at 90 dBA for 8-hour TWA. Action level is 85 dBA requiring hearing conservation program. Exposure above 90 dBA requires hearing protection and administrative controls.
TWA = 16.61 x log10(D/100) + 90, where D is noise dose. Dose = sum of (actual exposure time / allowable time at each level) x 100%. Use 5 dB exchange rate for OSHA (3 dB for NIOSH).
Choose based on noise level: Foam earplugs (NRR 25-33) for moderate noise, earmuffs (NRR 20-30) for comfort, dual protection (earplugs + earmuffs) for extreme noise above 100 dBA. Ensure proper fit and training.
OSHA requires annual audiometric testing for employees exposed to 85+ dBA TWA. Monitor noise when equipment changes, new processes begin, or employees report concerns.
Table saw: 85-95 dBA, Router: 95-105 dBA, Planer: 90-100 dBA, Dust collector: 80-90 dBA, Circular saw: 100-110 dBA. Actual levels vary by tool condition, material, and environment.
Noise dose is percentage of allowable daily exposure. 100% dose = PEL (90 dBA for 8 hours). Dose = (C1/T1 + C2/T2 + ...) x 100%, where C is actual exposure time and T is allowable time at that level.