The noise dosimeter in dB Ride is for guidance only. It is not a measurement to ISO 9612 or OSHA's monitoring rules, and a phone is not a calibrated instrument. Workplace noise assessments are the employer's responsibility and rely on competent persons using IEC 61672 or IEC 61252 instruments. If you think your workplace is too loud, talk to your safety officer, occupational health service or employee representative.
The numbers that matter: dose, TWA, LEX,8h and peak
In occupational noise, what counts is not the level at a single moment but the noise dose over the day:
- Dose: the share of the allowed daily exposure, in percent. 100 % means the reference exposure of the standard has been reached.
- TWA (OSHA, NIOSH) / LEX,8h (EU): the 8-hour average that corresponds to that dose. Short, very loud phases count heavily; quiet breaks bring the value down.
- Peak (LCpeak): the highest C-weighted peak sound pressure, e.g. from hammer blows, compressed air or bangs – exposure that is too short to show up in the average.
OSHA, NIOSH and EU limits compared
| Standard | 100 % dose | Exchange rate | Levels counted | Key values |
|---|---|---|---|---|
| OSHA PEL (29 CFR 1910.95) | 90 dB(A) over 8 h | 5 dB | from 80 dB(A), slow | Action level 85 dB(A) TWA (= 50 % dose): hearing conservation program. Peak max. 140 dB |
| NIOSH REL (1998) | 85 dB(A) over 8 h | 3 dB | from 80 dB(A), slow | Recommended limit 85 dB(A) TWA. No exposure above 140 dB peak |
| EU 2003/10/EC | 85 dB(A) over 8 h (in dB Ride) | 3 dB | all (energy-based) | Lower action values 80 dB(A) / 135 dB(C), upper 85 dB(A) / 137 dB(C), limit values at the ear 87 dB(A) / 140 dB(C) |
OSHA's PEL is legally binding in the US; NIOSH is a recommendation based on newer research and is stricter. In the EU, the action values apply without hearing protection; the limit values apply at the ear, i.e. taking hearing protection into account. Germany is stricter still: under hearing protection, 85 dB(A) and 137 dB(C) must not be exceeded.
The exchange rate: double the energy, half the time
Decibels are logarithmic. With the 3 dB rule (NIOSH, EU), every +3 dB halves the time until 100 % dose. OSHA uses a 5 dB rule, which allows considerably more time at high levels.
| Level | NIOSH / EU | OSHA |
|---|---|---|
| 85 dB(A) | 8 h | 16 h |
| 88 dB(A) | 4 h | approx. 10.6 h |
| 90 dB(A) | approx. 2.5 h | 8 h |
| 91 dB(A) | 2 h | approx. 7 h |
| 94 dB(A) | 1 h | approx. 4.6 h |
| 95 dB(A) | approx. 48 min | 4 h |
| 97 dB(A) | 30 min | approx. 3 h |
| 100 dB(A) | 15 min | 2 h |
That is why short, loud jobs like grinding, hammering or leaf blowing matter: with the 3 dB rule, 15 minutes at 100 dB(A) carry as much sound energy as a whole working day at 85 dB(A).
How to measure with the noise dosimeter in dB Ride
Open the dosimeter
Choose “Noise dosimeter (occupational)” in the menu – or long-press the app icon to open it directly. Pick the standard (EU, NIOSH or OSHA) and your shift length, e.g. 8 hours.
Place the phone sensibly
The microphone must be uncovered – not in a trouser pocket or under a jacket. A position close to your head is most meaningful, e.g. a shoulder or chest mount with the microphone facing out. For a rough estimate, a fixed spot at the workstation also works.
Start and get to work
The dosimeter keeps measuring in the background, even with the screen off. The notification shows the dose and LAeq. Optionally, a level alarm alerts you by vibration or notification when a threshold is exceeded.
Stop and review
Stop after your shift. The measurement is saved and can be shared as a PDF report – with standard, duration, readings and notes on the limits.
What the app shows
- LAeq since start and TWA / LEX,8h so far
- Projection to your shift length: TWA / LEX,8h and dose if the average exposure so far continues for the whole shift
- Dose so far and time to 100 % at the current average exposure
- LAFmax and LCpeak max with a traffic light for peaks
- which value has been reached (action level, PEL, REL, action or limit values) and a note if there were gaps in the measurement
Dose and averages are always measured A-weighted and peaks C-weighted – regardless of the weighting you chose on the meter screen.
Limits: what a phone cannot do
- Very high levels: phone microphones usually clip above 110–120 dB. Peaks above 135 dB(C) – impact wrenches, nail guns, gunshots – can usually not be captured. The peak traffic light is only an indication, not proof.
- Accuracy: without calibration, absolute readings can be off by a few dB depending on the phone model. The calibration assistant and a reference meter fix that; device profiles exist for some models. More in Phone decibel meter accuracy.
- Hearing protection: the app measures ambient noise, not the level under your earmuffs or earplugs. Their attenuation is not included.
- Position: a phone on the workbench measures something different from a dosimeter on your shoulder. Same position means comparable readings.
Beyond work
Noise damages hearing in your free time as well. The dosimeter shows what adds up during DIY with a circular saw or rotary hammer, at a long concert or on a motorcycle. Under a helmet at 100 km/h (62 mph), 85–95 dB(A) is common – more in Motorcycle helmet noise. On a motorcycle: start before riding, stow the phone safely and don't operate it while riding.
Frequently asked questions
Can a phone app replace a noise dosimeter?
Not for compliance. Workplace noise assessments call for competent persons using instruments to IEC 61672 (sound level meters) or IEC 61252 (personal sound exposure meters), following methods such as ISO 9612 or OSHA's monitoring rules. A phone is not a calibrated instrument. For guidance – to see whether a job gets close to the action levels – a dosimeter app is still useful.
At what decibel level is hearing protection required?
Under OSHA, a hearing conservation program is required from an 8-hour TWA of 85 dB(A) (the action level), and the permissible exposure limit is 90 dB(A). NIOSH recommends 85 dB(A) as an 8-hour TWA with a 3 dB exchange rate. In the EU, employers must provide hearing protection above 80 dB(A) LEX,8h or 135 dB(C) peak and make sure it is worn from 85 dB(A) or 137 dB(C).
What is the difference between LAeq, TWA and LEX,8h?
LAeq is the energy average over the actual measurement time. LEX,8h (EU) normalises a working day's exposure to 8 hours: 4 hours at 88 dB(A) followed by quiet gives an LEX,8h of 85 dB(A). TWA (NIOSH/OSHA) is the 8-hour average calculated with the exchange rate of the respective standard.
Why does dB Ride show a different dose for OSHA than for NIOSH?
The standards calculate differently: NIOSH and the EU base 100 % on 85 dB(A) over 8 hours with a 3 dB exchange rate, OSHA on 90 dB(A) with a 5 dB exchange rate. The same working day therefore gives a different percentage depending on the profile.
Does the noise dosimeter in dB Ride cost anything?
No. dB Ride is completely free – no ads, no in-app purchases, no account. Your measurements stay on your device.
Keep an eye on your noise dose – for free.
dB Ride is free for Android and iOS – no ads, no in-app purchases, no account. The noise dosimeter with OSHA, NIOSH and EU profiles, level alarm and PDF report is available to everyone. And in the car, the app measures the noise at every speed.
Sources & notes
- OSHA: 29 CFR 1910.95 Occupational Noise Exposure (Table G-16, action level, hearing conservation program).
- NIOSH: Criteria for a Recommended Standard – Occupational Noise Exposure, Revised Criteria 1998, Publ. No. 98-126.
- Directive 2003/10/EC (noise), Articles 2 and 3; German LärmVibrationsArbSchV § 8.
- ISO 9612: Determination of occupational noise exposure (engineering method). IEC 61672-1 (sound level meters), IEC 61252 (personal sound exposure meters).
- Times to 100 % dose: own calculation from criterion level and exchange rate. Not legal or medical advice.