Enter Workday Exposures
Example Data Table
Sample inputs and typical output using an 8-hour shift and OSHA settings.
| Example task | Level (dBA) | Duration (h) | Allowable time (h) | Partial dose (%) |
|---|---|---|---|---|
| Jackhammer | 100 | 1.00 | 2.0000 | 50.00 |
| Cut-off saw | 95 | 2.00 | 4.0000 | 50.00 |
| General site | 85 | 5.00 | 16.0000 | 31.25 |
Total dose ≈ 131.25% and OSHA TWA ≈ 91.96 dBA.
Formula Used
How to Use This Calculator
- Choose OSHA or NIOSH, then set the shift length.
- Enter each task’s A-weighted level and duration in hours.
- Optionally enable hearing protection and enter an NRR value.
- Click calculate to view dose, equivalent levels, and task details.
- Use CSV or PDF exports for documentation and toolbox talks.
Professional Article
Eight focused notes to support safer construction noise planning.
Why Noise Exposure Matters on Sites
Construction crews work near impulsive and continuous noise. Repeated high exposure can cause permanent hearing loss, tinnitus, fatigue, and reduced awareness. Many safety programs target 100% daily dose for the chosen standard. This calculator converts task logs into dose so supervisors can verify limits and plan quieter sequences.
Understanding dBA and A-weighting
Sound meters often report A-weighted decibels (dBA), approximating human hearing. A 10 dB increase is perceived roughly as twice as loud and represents ten times more energy. Because energy rises fast, short loud tasks can dominate the daily total even when most work is moderate.
Dose Method and Exchange Rate
Dose combines time and level. For each task, allowable time T comes from the criterion level and exchange rate: every exchange-rate increase halves allowable time. With a 5 dB exchange rate, 95 dBA allows half the time permitted at 90 dBA. With 3 dB, allowable time drops faster. Example: at 100 dBA for an 8-hour shift, OSHA allows about 2 hours, while NIOSH allows about 0.25 hours. This difference drives higher NIOSH dose values for time on task directly.
OSHA vs NIOSH in Practice
OSHA commonly uses a 90 dBA criterion with a 5 dB exchange rate, while NIOSH uses 85 dBA with a 3 dB exchange rate. Selecting NIOSH usually yields a higher dose for the same tasks. Some projects adopt NIOSH-style goals for prevention, then document both results for reporting.
Typical Construction Sound Levels
Typical ranges: hand grinder 90–100 dBA, circular saw 95–105 dBA, jackhammer 100–110 dBA, dozer cab 80–90 dBA, heavy truck pass-by 85–95 dBA. Levels vary with distance, enclosure, maintenance, and materials. Enter measured values when possible, or start conservative and refine later.
Using Hearing Protection Inputs
When hearing protection is enabled, the calculator applies an estimated attenuation from the labeled NRR. Field performance is often lower than the label, so the calculation uses a conservative adjustment and optional derating. Compare protected versus unprotected results to support selecting plugs, muffs, or dual protection.
Interpreting Dose, Lex, and TWA
Dose% shows how the day compares to the chosen limit. Lex is an energy-equivalent level normalized to the shift, useful for tracking trends. Leq summarizes the tasks you entered over their total time. For the OSHA model, TWA is also shown as a familiar indicator derived from dose.
Control Strategies and Documentation
Use results to prioritize controls: increase distance, add temporary barriers, rotate workers, schedule noisy tasks when fewer people are nearby, maintain tools, or substitute quieter methods. Keep logs of levels, durations, and controls used. Export CSV or PDF for toolbox talks, daily reports, and audits.
FAQs
What inputs should I use if I do not have measurements?
Use conservative estimates from similar tools or vendor data, then update with meter readings. Enter a separate row for each distinct task, distance, or operating mode to improve accuracy.
Why does selecting NIOSH increase the dose?
NIOSH uses a lower criterion level and a 3 dB exchange rate, so allowable time decreases faster as level rises. The same duration at high levels contributes a larger fraction of the daily limit.
Does this replace a professional noise survey?
No. It is a planning and documentation aid. For compliance decisions, rely on calibrated instruments, qualified personnel, and site-specific procedures, especially for impulsive or highly variable noise.
How is hearing protection applied here?
It estimates attenuation using a conservative NRR adjustment, then applies optional derating. Real-world fit and wear time matter, so treat protected results as an estimate and verify with field checks.
What does Lex over shift mean?
Lex is an energy-equivalent level normalized to the full shift length. It helps compare days with different task mixes by expressing the overall exposure as one consistent dBA value.
Why can a short loud task dominate the results?
Decibels are logarithmic. A small level increase represents much more energy, so minutes at very high levels can add as much dose as hours of moderate noise.
What actions can reduce dose quickly on site?
Increase distance, add barriers, maintain equipment, select quieter methods, limit time near sources, and schedule noisy work when fewer workers are nearby. Combine engineering and administrative controls before relying on protection.
Protect crews by planning noise controls and monitoring daily.