Case study: a joinery workshop where 10 of 13 tools were over the limit

The site

A joinery and cabinet-making workshop in the West Midlands, with a mill and a workshop running saws, routers, sanders, drills and a CNC, plus nail guns and impact drivers. We measured thirteen tools and areas to Class 1 standard and built exposure groups for the mill, the workshop and the CNC.

What we found

Ten of the thirteen tasks measured at or above the 85 dB(A) upper action value — from a metal saw at 96.8 dB(A) down through routers, cross-cut and rip saws, sanders and the CNC. Only the wall saw (82.9) and the ambient positions were lower. The nail gun produced the loudest impulse at 121.6 dB(C), still well under the 135 dB(C) peak action value.

The insight that pays for the survey

When almost every tool in the shop is over the limit, the temptation is to hand out whatever ear defenders are in the cupboard. The assessment did the arithmetic instead: modelled across a realistic working day, a correctly-worn SNR 18 protector brings the mill group to 75.6 dB(A), the workshop to 74.5 and the CNC operator to 72.1 — all comfortably safe, and crucially not over-protected, so people can still hear machines, colleagues and alarms and are far more likely to keep the protectors on. Getting the protector grade right is the difference between protection on paper and protection in practice.

What the client got

• A single, correct protector specification (SNR 18) covering the whole shop that lands every exposure group in the safe 72–76 dB(A) range at the ear.
• Mandatory Hearing Protection Zones for the ten tasks over the upper action value, with signage and defined boundaries.
• Audiometry for the mill, workshop and CNC groups, and a source-control shortlist (blade and cutter condition, damping, local screening, quieter procurement) so the noise comes down over time.

That is the difference between a survey that just says “you're over the limit” and one that tells you exactly where to act — and keeps it current, which is what the 4-Year Care Plan is for.