Hearing conservation programme — built to pass inspection and to actually work
Once any employee's eight-hour average exposure reaches 85 dBA, Thai law requires the employer to have a written hearing conservation programme, under the Department of Labour Protection and Welfare notification of B.E. 2561 issued beneath the 2559 Ministerial Regulation on heat, light and noise. The programme is not a single noise survey report. It is a system: a noise survey and noise map, individual exposure assessment, audiometric testing, hearing protection, training, record-keeping and an annual review.
The problem we most often see is not the absence of a programme but a programme written to pass. Convenient measurement points, a quiet shift, last year's form copied forward. The result is a document an experienced labour inspector can read as unrepresentative, and employees who are still losing hearing. Geonoise builds programmes in which every number was actually measured, by the method the regulation prescribes — and we do not sell the earplugs or the enclosures the programme will recommend.
What the regulation requires
A hearing conservation programme under the B.E. 2561 notification must contain every element below, and must be reviewed at least annually.
- Policy and responsibilities — in writing, with a named person accountable for each part
- Noise survey and measurement — every area where employees work, with calibrated instruments and the method the Ministerial Regulation prescribes, plus a map showing where levels are 85 dBA or above
- Individual exposure assessment — the 8-hour TWA for each job position, from personal dosimetry or from area levels and time in each area
- Audiometric testing — a baseline before starting work or within 30 days, then at least annually, compared against the baseline
- Noise control — at source and along the path, before relying on personal protection
- Hearing protectors — selected by the attenuation the measured level actually needs, not by price
- Employee training — for everyone working where levels reach 85 dBA
- Records — survey results, audiometric results and actions taken, available to the labour inspector
What we do
- A full plant noise survey with Class 1 sound level meters calibrated by an ISO/IEC 17025 laboratory, during the shift and the production conditions people actually work in — not with half the plant stopped.
- A noise contour map of the production area with the 80, 85 and 90 dBA lines, defining the mandatory-protection zone and the areas where engineering control is due.
- Personal exposure assessment by shift-long dosimetry for positions that move between areas.
- Ranking of the dominant sources by frequency analysis and, where several sources sit close together, by acoustic camera — so that noise-control money goes to the right machine.
- The complete written programme, every element the B.E. 2561 notification requires, with record forms the plant can keep using itself.
- On-site training and an annual review as a continuing service, where you want this to run itself every year.
Why the measurement is the heart of the programme
Every part of the programme rests on the survey numbers. If they are lower than reality, employees who should be in the programme are left out, the protectors chosen are insufficient, and a deteriorating audiogram has no explanation. An experienced inspector can tell when a noise map was measured. We measure under real operating conditions, record the production state in the report, and have the survey signed by an analyst holding the DLPW noise-analyst licence — the credential a labour inspector expects to see on it.
From one programme to a system that runs every year
The programme must be reviewed annually and updated when a machine is added, the layout changes or an employee's hearing test changes. Most plants do the first one well and then let it age until an inspection finds it. We therefore offer it as an annual cycle: re-survey of the areas that changed, an updated noise map and programme roster, and a document review — so the record accumulates as evidence that the employer takes this seriously.
What you receive
- Noise survey report with contour map, a table of every measurement point, and the production conditions at the time — signed by a licensed analyst
- Exposure table by job position (8-hour TWA) and the roster of employees who must be in the programme
- The complete written hearing conservation programme to the B.E. 2561 notification, with record forms
- Noise-control recommendations ranked by effect per baht, and the attenuation hearing protectors must provide in each area
- Training materials and attendance records, where training is in scope
Standards & method
Ministerial Regulation on standards for heat, light and noise B.E. 2559 · DLPW Notification on hearing conservation measures B.E. 2561 · ISO 9612 (occupational noise exposure) · IEC 61672-1 Class 1 · IEC 61252 (personal sound exposure meters) · instruments calibrated by an ISO/IEC 17025 accredited laboratory
FAQ
Does our plant need a hearing conservation programme?
Yes, if any employee's 8-hour average exposure reaches 85 dBA. The only way to know is a survey under real production conditions. Plants with heavy machinery, compressed-air systems or packaging lines usually qualify in at least some areas.
We already have an annual noise measurement report. Is that enough?
No. The report is one element. The programme must also contain the noise map, individual exposure assessment, audiometry, hearing protection, training, records and an annual review, as the B.E. 2561 notification lists. The inspector checks the system, not one report.
What is a noise map and why is it required?
A plan of the production area showing the measured levels and the 85 dBA boundary — the zone where hearing protection is mandatory and warning signs are required. It is usually the first document an inspector asks for, and it is the basis for deciding which employees belong in the programme.
Who is allowed to carry out the survey?
The law sets qualifications for the person who measures and analyses. Our analyst holds the DLPW noise-analyst licence, and the report is signed by a named person, not an anonymous subcontractor.
When should the measurement be done?
During the shift and production conditions employees actually work in, including the loudest part of the cycle. Measuring with part of the plant stopped produces numbers that are lower than reality, and the production record in the report shows an inspector exactly that.
Is audiometric testing required, and who does it?
Yes, for employees exposed at 85 dBA or above: a baseline before starting or within 30 days, then at least annually. Audiometry is carried out by a medical provider; we do not provide it ourselves, but the programme we write specifies who is tested, when, and what the results are compared against.
What if an area exceeds 85 dBA?
The order the law and good engineering both require is control at source and along the path first, then personal protection. We rank the dominant sources and propose measures by effect per baht, and we do not sell the materials or equipment we recommend.
How long does it take?
A medium-sized plant takes one to two days on site including shift-long dosimetry, and about two weeks for the documentation. Programme and price come with the proposal once we know the floor area and the number of job positions.
Can this run as an annual service?
Yes, and it is the way to keep the programme from going stale. We offer an annual cycle covering re-survey of changed areas, an updated map and roster, and a document review — see the Corporate Acoustic Compliance Programme.