Octave Band Hearing Protection Calculator
The octave band method is the most accurate way to estimate how much hearing protection a worker is actually getting. It uses octave-band attenuation data from the protector’s datasheet and an octave-band breakdown of workplace noise from a survey. The output is the A-weighted level at the ear, used to check protection against the action and limit values in the Control of Noise at Work Regulations 2005.
| Frequency (Hz) | 63 (optional) | 125 | 250 | 500 | 1000 | 2000 | 4000 | 8000 |
|---|---|---|---|---|---|---|---|---|
| Mean attenuation (dB) | ||||||||
| Standard deviation (dB) | ||||||||
| Assumed protection (dB) | — | — | — | — | — | — | — | — |
| Frequency (Hz) | 63 (optional) | 125 | 250 | 500 | 1000 | 2000 | 4000 | 8000 |
|---|---|---|---|---|---|---|---|---|
| Unprotected spectrum (dB) | ||||||||
| Protected spectrum (dB) | — | — | — | — | — | — | — | — |
Enter values to see the result
Fill in the protector’s octave-band attenuation and standard deviation values, then the workplace noise spectrum.
How to Use This Calculator
Enter the hearing protector’s mean attenuation and standard deviation across the octave bands. These values appear on every conforming protector’s datasheet. Then enter the unweighted (linear) octave-band noise levels from your workplace noise survey. The calculator works out the Assumed Protection Value (APV) at each frequency, the protected spectrum at the ear, and the overall A-weighted level at the ear with the 4 dB real-world correction added.
Why the Octave Band Method Is the Most Accurate
The HML and SNR methods compress octave-band performance into one or three numbers, which means they make assumptions about the shape of the workplace noise. The octave band method doesn’t. If the noise has a strong low-frequency component (compressors, large fans, presses) or a strong high-frequency component (rotating tooling, escaping air), the protector’s performance will differ from its single-number rating. Use this method when noise is concentrated in particular bands and getting the figure right matters.
What the Result Tells You
The calculator returns an HSE protection rating. The target is a level at the ear between 70 and 80 dB(A). Above 85 dB(A) the protector is under-protecting. Below 70 dB(A) it’s over-protecting, which can make warnings and speech hard to hear. If you’re not in the target range, look at a different protector or, better, reduce the noise at source. For workplaces dealing with regular HSE attention, a proper noise risk assessment backed by octave-band data is the cleanest evidence base.
This calculator uses the method published in BS EN ISO 4869-2 and HSE document L108. It’s intended as a guide.
About Advanced Noise Solutions
Advanced Noise Solutions is a specialist industrial noise consultancy based in St Albans. For 38 years we’ve helped UK manufacturers solve noise problems where they actually start, at the source, rather than wrapping the whole machine in an acoustic enclosure. Our AcoustiFix methodology typically delivers higher dB reductions than enclosures, at a fraction of the cost, with none of the access, visibility or maintenance trade-offs.
If your hearing protector isn’t bringing exposure into the 70 to 80 dB(A) target range, hearing protection alone isn’t the answer. We diagnose the real source of the noise and engineer a fix that brings unprotected exposure down. Get in touch or call us on 01727 864667 to talk it through.