Noise & Hearing Conservation

Back to all safety programs

Overview

Noise-induced hearing loss is permanent but entirely preventable.

Action level ~85 dBA, legal limit 90 dBA; engineering controls come first.

When the programme applies

Areas where 8-hour exposure reaches about 85 dBA.
Work near rotating machinery, compressors and turbines.
Grinding, chipping and impact or impulse noise.
Any zone where you must shout to be heard at arm's length.

Step-by-step procedure

Carry out a noise survey and produce a noise map.
Calculate each worker's 8-hour TWA against the action level.
Apply engineering controls first — enclosures, silencers, maintenance.
Add administrative controls — rotation and signage of >85 dBA zones.
Issue hearing protection with adequate NRR.
Require double protection above about 100 dBA.
Run baseline and annual audiometric tests; review for early shifts.
Train workers, monitor compliance, re-survey on changes.

Key controls

Hierarchy — engineer first, then administrative, then PPE.
Hearing protection chosen on real NRR, comfort and fit.
Special attention to impulse noise, which damages hearing instantly.

Roles & responsibilities

Role	Responsibility
HSE / Occupational Health	Runs surveys, sets controls, manages audiometric testing.
Supervisor	Enforces zone rules, rotation and protection use.
Workers	Wear protection correctly, follow signage, attend tests.

Common mistakes to avoid

Relying on earplugs while ignoring engineering fixes.
Wearing protection loosely, losing most of its NRR.
Skipping annual audiometry, so early loss goes undetected.

Legal requirements (Thailand)

Occupational Safety, Health and Environment Act B.E. 2554 (2011) — the governing workplace-safety law in Thailand.
Ministerial Regulation on OSH for heat, light and noise B.E. 2559 (2016).

Frequently asked questions

What is Noise & Hearing Conservation?

Noise-induced hearing loss is permanent, painless and entirely preventable. Around heavy plant, compressors, grinders and impact tools, daily noise can easily exceed safe limits. A hearing conservation programme measures exposure, controls it at source where possible, and protects workers who remain at risk.

Who is responsible?

HSE / Occupational Health: Runs surveys, sets controls and manages the audiometric testing programme.; Supervisor: Enforces zone rules, rotation and the wearing of hearing protection.; Workers: Wear protection correctly, follow signage and attend audiometric tests.

What are the most common mistakes to avoid?

Relying on earplugs while ignoring cheap engineering fixes at source. Wearing protection loosely or incorrectly, losing most of its NRR. Skipping annual audiometry, so early hearing loss goes undetected.

References — Thai heat/light/noise regulation B.E. 2559, OSH Act B.E. 2554; NIOSH/OSHA concepts.