| 📋 Article Summary — Workplace Noise Survey | |
|---|---|
| Entity | Anitech Group — Occupational Hygiene |
| Article Type | Methodology Guide / Compliance Reference |
| Target Audience | Occupational hygienists, WHS managers, noise assessors, hearing conservation programme managers |
| Key Entities | Safe Work Australia, AS/NZS 1269 series, AS IEC 61672 (sound level meters), AIOH |
| Regulations & Standards | AS/NZS 1269.1:2005 (noise assessment and measurement); AS IEC 61672-1:2019 (electroacoustics — sound level meters); WES for noise: LAeq,8h 85 dB(A), peak 140 dB(C) |
| Key Fact 1 | Australia uses the 3 dB exchange rate for noise dosimetry (every 3 dB increase halves the permitted exposure time) — stricter than the US OSHA 5 dB exchange rate but identical to the ACGIH/NIOSH standard. |
| Key Fact 2 | An integrating-averaging sound level meter (Type 1 or Type 2 to AS IEC 61672) is required for noise measurement in Australian workplaces — smartphone apps and simple sound meters are not adequate for WES compliance assessment. |
| Key Fact 3 | A noise survey that only measures LAeq,8h without also measuring LCpeak will miss impulse noise hazards — both exposure metrics must be assessed and compared to their respective action levels. |
| What This Covers | Noise survey types (dosimetry vs sound level mapping), instrumentation specification, measurement positions, SEG design for noise, frequency analysis for source identification and control selection, reporting requirements |
| What This Does Not Cover | Noise in community environments (AS 4959), aircraft noise assessment (ANEF), environmental noise — separate standards from occupational noise |
| Primary CTA | Contact Anitech for noise surveys, octave-band analysis and hearing conservation programme design |
| Read Time | 10 min read |
Workplace Noise Survey: Planning and Conducting a Compliant Assessment
A workplace noise survey is a systematic measurement of sound levels and worker exposures to quantify the noise hazard, compare results to the Workplace Exposure Standards, identify noise sources, and provide data for engineering control specification. Like air monitoring for dust and chemicals, a noise survey that is poorly designed or uses non-compliant instrumentation produces data that cannot be used for legal compliance purposes — and may provide false assurance while workers’ hearing is being damaged.
Australian Noise WES Values
Safe Work Australia WES values for noise:
- 8-hour equivalent continuous sound pressure level (LAeq,8h): 85 dB(A) — the primary occupational noise standard. Noise above this level requires controls and a hearing conservation programme
- Peak sound pressure level (LCpeak): 140 dB(C) — the limit for instantaneous peak noise, relevant to impulse/impact noise (explosions, gunfire, punch presses)
- Action level: 50% dose (equivalent to LAeq,8h 82 dB(A)) triggers hearing conservation requirements (hearing protection provision, audiometric testing)
Australia uses the 3 dB exchange rate — for every 3 dB increase above 85 dB(A), the permissible exposure time halves. A worker exposed to 88 dB(A) can only work for 4 hours at that level; 91 dB(A) allows only 2 hours.
Types of Noise Measurement
Noise Dosimetry (Personal Exposure Measurement)
Noise dosimeters are small, wearable devices clipped near the worker’s ear throughout the work period. They integrate all noise over time to calculate the cumulative noise dose and LAeq,8h directly. Dosimetry gives the most accurate picture of actual personal exposure — it captures all noise encountered, including variable-level tasks, movement between areas, and brief high-level events. It is the primary method for WES compliance assessment per AS/NZS 1269.1.
Sound Level Measurement (Area Surveys)
Sound level meters positioned at fixed locations or held by the assessor measure instantaneous sound levels at specific positions and times. Sound level measurement is used for: identifying noise sources for engineering control; mapping noise levels across a work area; octave-band frequency analysis for noise specification; and verifying control effectiveness after engineering intervention. It does not directly measure personal exposure but informs dosimetry survey design and control priority-setting.
Instrumentation Requirements
Sound Level Meters
AS IEC 61672-1:2019 classifies sound level meters as Type 1 (precision) or Type 2 (general purpose). For occupational noise assessment in Australia:
- Type 1 meters for measurements supporting WES compliance assessment and legal proceedings
- Type 2 meters acceptable for screening surveys and qualitative assessments
- All meters must have A-weighting and C-weighting frequency responses
- Integrating-averaging capability (for LAeq measurement) is required — simple “RMS” meters without integration are inadequate
- NATA-calibrated acoustic calibrator for field calibration before and after each measurement period (±0.5 dB tolerance)
Noise Dosimeters
Noise dosimeters must be Type 2 equivalent or better, configured to the Australian exchange rate (3 dB), threshold of 80 dB(A) (minimum level counted toward dose), and criterion level of 85 dB(A). The dosimeter microphone is clipped within 20 cm of the worker’s ear (typically lapel or collar). Workers must be instructed not to cover, touch or reposition the microphone during sampling.
Survey Design — SEGs for Noise
The SEG approach applies to noise as to dust — workers with similar noise exposure profiles are grouped. Initial area sound level measurements inform the SEG design: workers in areas with similar noise levels and task profiles are grouped. Dosimetry is then conducted on a representative sample of each SEG. A minimum of 6 dosimetry measurements per SEG is recommended for statistical inference about the full SEG exposure distribution.
Octave-Band Frequency Analysis
A-weighted overall sound level measurements tell you whether a noise problem exists. Octave-band frequency analysis (measuring sound levels in eight standardised octave bands: 63, 125, 250, 500, 1000, 2000, 4000, 8000 Hz) tells you:
- The frequency content of the noise — essential for engineering control specification (damping, isolation, silencer design) and HPD selection verification
- Whether the noise is dominated by low-frequency components (often from machinery resonance — requires isolation), mid-frequency (typically mechanical impact — enclosure or damping), or high-frequency (aerodynamic — silencer, enclosure)
Reporting
A compliant noise survey report includes: site description and map; instrumentation details and calibration records; measurement positions and times; individual dosimetry results; SEG assignment and statistical summary; WES comparison for each SEG; identified noise sources with contribution analysis; prioritised control recommendations; and monitoring programme recommendations.