Industrial and Workplace Noise Measurement
Geonoise's industrial noise measurement service answers the three questions a factory has to be able to answer: is the noise employees receive within the Ministerial Regulation B.E. 2549 limits; is the noise at the boundary and at the neighbouring houses within the Pollution Control Department limits and the EIA conditions; and if not, which machine has to be fixed, with what measure, at what cost. We measure with Class 1 instruments calibrated by an ISO/IEC 17025 accredited laboratory, by the methods the law prescribes, and the reports are signed by the registered professionals the law requires.
What separates us from a measurement contractor is that we do not stop at the number. The team combines acoustic engineers, Thai-registered industrial hygienists and environmental scientists, and the results become a noise map, a frequency analysis and a Good / Better / Best list of measures with indicative costs. We sell no materials and install nothing, so the recommendation is tied to no supplier — see why independent.
What does the industrial noise measurement service cover?
A factory has two groups of receivers protected by different laws: the employees inside and the community outside the fence. The service is built to answer both in one site visit.
- Workplace noise measurement under the Ministerial Regulation on heat, light and noise B.E. 2549, as area surveys and personal dosimetry to ISO 9612
- Boundary and neighbour measurements by the Pollution Control Department method — Leq 24 h, maximum level and disturbance level — for the Department of Industrial Works, the local authority or an EIA; see environmental noise
- Machine-by-machine emission measurement to ISO 11201 / ISO 3744, to rank which machines dominate the total and to check what the manufacturer guaranteed
- 1/1 and 1/3 octave analysis to separate tonal, low-frequency and impulsive noise, each of which needs a different measure
- Impulse and C-weighted peak measurement in press shops, forging and other intermittent-noise work, where the regulation's 140 dB ceiling requires work to stop
- Noise contour maps of the production floor to define the hearing-protection zones and warning-sign areas the law requires
- Source location with the acoustic camera where several machines run at once
How is workplace noise measured so that it is legally valid?
The Ministerial Regulation B.E. 2549 and the Department of Labour Protection and Welfare notifications prescribe both the limits and the method. A report that does not follow the method is returned even when the numbers pass. Every report of ours covers:
- The time-weighted average (TWA) against 90 dBA for 8 hours, 87 dBA for 12 hours and the table values for shorter days, using the 5 dB exchange rate the regulation sets
- Screening of positions where the TWA reaches 85 dBA, which triggers a hearing conservation programme under the 2010 notification
- Measurement positions at ear height, at the prescribed distance from the worker, covering every shift and every representative production condition — not the half-hour when the line idles
- Personal dosimeters for workers who move between areas and area measurements for fixed positions, following ISO 9612
- Field calibration before and after with an acoustic calibrator, and the ISO/IEC 17025 calibration certificates appended
- Certification by the registered professional and a report format the employer can submit to the Director-General within the 30 days the law allows
Which limits apply at the factory boundary?
The community around a plant is protected by the Environmental Quality Act, the Factory Act and the Public Health Act, which use different numbers and different measurement methods.
- General level: Leq 24 h not above 70 dBA and a maximum of 115 dBA under National Environment Board Notification No. 15
- Disturbance level: not more than 10 dBA above background under Notification No. 29 and the latest Pollution Control Department method — the criterion most complaints are decided on
- Project-specific EIA conditions, which may fix the measurement points, the frequency and stricter values than the general limits
- Positions at the boundary and at the most sensitive receiver, with weather and plant-operating conditions logged, because a plant at half load is not the plant the complaint is about
- All limits with their sources are on the Thailand noise limits reference; the legal framework is in Thai noise law
How does the work run?
Most industrial noise projects take one to three days on site and the report follows within ten working days. The standard sequence:
- Scope: the plant layout, number of shifts, main machines, complaint or EIA points and the limits to report against — quote within one working day
- Site measurement: area survey, personal dosimetry, boundary and receiver measurements and machine-by-machine emission, under real production conditions
- Analysis: TWA and dose per job position, frequency spectra, the noise map and a ranking of sources by their share of the total
- Option modelling: a SoundPLAN model to test measures before money is spent — enclosure, silencer, relocating a machine, a barrier — see noise modelling
- Report: a Thai edition for the authorities and an English edition for the parent company, with Good / Better / Best recommendations and indicative costs
- Verification: measurement after the measures are installed, to prove the result to the authority, management and the community
Which noise-control measures actually work in a factory?
Thai law sets the order: source and path first, personal protection only where that is still insufficient. The measures we design most often:
- Machine enclosures with silenced ventilation openings — 15–25 dB when the sealing and the cooling are designed properly
- Silencers on fans, compressors, exhausts and pressure-relief valves, which are often the loudest sources and the most overlooked
- Vibration isolation on spring or rubber mounts, to stop structure-borne sound reaching the offices or the neighbouring building — see vibration monitoring
- Maintenance: shaft alignment, bearing replacement and fan balancing, which remove the tonal components behind complaints at almost no cost
- Layout and scheduling: moving loud machines away from the community side and keeping loud operations out of the night
- Where PPE is still needed: attenuation (SNR/NRR) matched to the measured level, not over-specified to the point where workers take it off, with warning signs in the zones above the limit
What you receive
- A workplace noise report in the format the Department of Labour Protection and Welfare requires, signed by the registered professional
- An environmental noise report at the boundary and the receivers by the Pollution Control Department method, for the Department of Industrial Works, the local authority or the EIA
- Noise contour maps, frequency spectra and a ranked source table
- Good / Better / Best recommendations with modelled results and indicative costs
- Outline designs for enclosures, silencers and vibration isolation that any contractor can price
- Calibration certificates and the field calibration log appended — see what a measurement report contains
Why Geonoise
- A mixed team of acoustic engineers and industrial hygienists, so the labour-law side and the environmental side are answered in one set of reports
- Class 1 instruments to IEC 61672-1 and dosimeters, every one calibrated by an ISO/IEC 17025 laboratory
- ISO 9001:2015 quality management for acoustic and vibration consulting
- No materials sold, nothing installed, so no incentive to recommend more than the plant needs
- Experience across food, petrochemical, automotive, power generation and industrial estates nationwide — examples in the case studies
Related services
This work is usually combined with Hearing Conservation Programme and Environmental Noise (EIA). For the background before you decide, read Noise Measurement: dB, dBA, Leq and Sound Level Meters in Noise 101.
FAQ
What does an industrial noise survey cost?
It depends on the number of positions, the number of shifts and whether boundary measurements or a noise map are included. A medium-sized plant needing one Ministerial Regulation report usually takes a day on site. Send the scope through the compliance measurement page and the quote follows within one working day.
How often must workplace noise be measured?
The Department of Labour Protection and Welfare notification requires the working environment to be measured and analysed at least once a year, and again whenever machinery, processes or the layout change in a way that could alter the levels.
What is the difference between 85 dBA and 90 dBA in Thai law?
90 dBA is the maximum 8-hour TWA an employee may receive under the Ministerial Regulation B.E. 2549. 85 dBA is the level at which the employer must start a hearing conservation programme, with audiometry, training and protection.
Can we measure with a phone app or a cheap meter ourselves?
For a first look, yes. A legal report needs instruments calibrated by an accredited laboratory, the prescribed method and the signature of a registered professional. An app-based report is rejected and costs you another cycle.
If the result exceeds the limit, can Geonoise fix it?
On the analysis and design side, yes: we identify the dominant sources, model the options in SoundPLAN, design the enclosure, silencer or isolation, and verify after installation. We sell no materials and do not install; the contractor is yours to choose.
Can one report serve both the labour department and the Department of Industrial Works?
No — the limits and methods differ, so they are separate reports. We plan one site visit to cover both the workplace and the boundary and issue a report per authority.