Noise, vibration and dust — exposure limits, hearing protector selection and corrective actions

Short answer: aim for roughly 70–80 dB(A) under the protector, not maximum attenuation. The simplest SNR method subtracts the manufacturer's SNR from the measured level. The more precise HML method accounts for the noise spectrum and works better for low-frequency machine noise.

Overprotection is a real risk: below about 70 dB(A) workers may miss warning signals, reversing trucks or instructions, and often remove protectors because they feel isolated. Consider comfort, glasses, helmets and heat — a protector that is not worn protects no one.

Hand-arm vibration comes from grinders, breakers and impact wrenches. The daily limit is 2.8 m/s² with an action value of 2.5 m/s². Whole-body vibration reaches the body through seats or floors — forklifts, loaders, platforms. Here the limit is 0.8 m/s² and the action value 0.5 m/s².

Effective measures include low-vibration tools, anti-vibration handles, regular servicing (worn bearings increase vibration), suspension seats, floor maintenance and task rotation. Anti-vibration gloves have limited effect and do not replace changes to tools or work organisation.

Short answer: the inhalable fraction is everything entering through nose and mouth; the respirable fraction is the finest particles reaching the alveoli. Many dusts therefore have two limits, with a much lower one for the respirable fraction. This is critical for crystalline silica (cutting concrete or stone, blasting), where the respirable limit in Poland is 0.1 mg/m³ and which is treated as a carcinogen.

The order of measures mirrors noise: change the method (wet cutting), local exhaust ventilation at the source, vacuuming instead of sweeping, and only then respiratory protection matched to the dust and concentration (e.g. a P2 or P3 half mask) with proper face fit.

The daily noise exposure level (LEX,8h) is compared with the 80 and 85 dB(A) action values. The maximum A-weighted level (LAmax) — limit 115 dB(A) — and the C-weighted peak level (LCpeak) — 135 dB(C) lower action value, 137 dB(C) limit — are assessed alongside. For uneven weeks a weekly level (LEX,w) is used.

Daily vibration exposure A(8) is the RMS acceleration normalised to 8 hours. Hand-arm vibration (HAV) enters through the upper limbs and can cause hand-arm vibration syndrome; whole-body vibration (WBV) is transmitted through the seat or floor and mainly loads the spine.

Inhalable and respirable dust fractions have separate limits. Carcinogenic dusts include respirable crystalline silica (quartz, cristobalite) and hardwood dust; work exposing staff to them enters the carcinogens register and stricter measurement intervals (see the exposure measurements guide).

Filtering facepiece classes FFP1, FFP2 and FFP3 (EN 149) differ in filtration and leakage. Selection guidance under EN 529 indicatively assumes protection up to about 4, 10 and 30 times the OEL, but actual selection depends on the dust, exposure and manufacturer advice. Tight-fitting respirators should pass a fit test — a leaking mask does not deliver its rated protection.

A result above a threshold in the Workplace exposure module can become an action in the CAPA module, with an owner, deadline and evidence of completion — for example an enclosure or extraction. A follow-up measurement closes the loop and shows whether the action worked.

In the PPE issuance module you assign hearing protectors or half masks to exposed workstations and employees, with issue history and replacement dates. A changed exposure level should also be reflected in the occupational risk assessment so the workstation card matches current conditions.