Noise Exposure Limit Value Calculator
Use this calculator when workers are wearing hearing protection. It estimates daily noise exposure at the ear and compares the result against the 87 dB(A) Exposure Limit Value set by the Control of Noise at Work Regulations 2005. Enter the H, M and L values from the protector’s datasheet, then the A-weighted and C-weighted noise levels for each task.
| Task | Noise levelLAeq in dB(A) | Noise levelLCeq in dB(C) | HP worn? | Hours(hh) | Minutes(mm) | Protected levelat the ear, dB(A) | Task LEP,ddB(A) | Task points |
|---|---|---|---|---|---|---|---|---|
| Daily totals | — | Daily LEP,d | — | — | ||||
Enter values to see the result
Add the H, M and L values for the protector at the top, then enter at least one task with A and C weighted levels and exposure time.
How to Use This Calculator
Enter the H (high), M (medium) and L (low) attenuation values from the hearing protector’s datasheet. For each task add the A-weighted and C-weighted noise levels (both come from a proper noise survey), set HP worn to Yes or No, and enter the time spent on that task. The calculator works out the protected level at the ear using the HML method, then combines tasks into a daily LEP,d compared against the 87 dB(A) Exposure Limit Value.
Why the Limit Value Is Different to the Action Values
The 80 dB(A) and 85 dB(A) action values are measured in the workplace, with no protection accounted for. The 87 dB(A) Exposure Limit Value is measured at the ear, after hearing protection. If a worker’s protected exposure exceeds 87 dB(A), the law has been broken regardless of what’s in the rest of the noise control programme.
The calculator adds 4 dB to the manufacturer’s stated attenuation. This is the HSE-recommended real-world correction, because the way protectors actually get worn rarely matches the lab. It also flags hearing protectors that over-protect (taking exposure below 70 dB(A) at the ear, which can make alarms, communication and traffic harder to hear) or under-protect (above 80 dB(A) at the ear).
This calculator follows the HML method used in HSE’s noise exposure spreadsheet. It’s a guide. If you’re using hearing protection to manage exposures close to the ELV, get a proper noise risk assessment done and plan to reduce noise at source.
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 protected exposure is close to or above the 87 dB(A) ELV, hearing protection on its own isn’t a long-term 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.