Noise dosimeters are essential instruments for monitoring sound exposure in the workplace. Selecting the optimal device requires distinguishing between a personal sound dosimeter and a general sound level meter, whilst adhering to established standards such as BS EN 61252. The selection process also involves a careful evaluation of specific device features to ensure full operational compliance.
A noise dosimeter, compliant with BS EN 61252:2022, is a wearable personal sound exposure meter typically positioned on the shoulder or collar. It measures parameters such as LAeq,T, LEX,8h (or TWA), and LZpeak/LCpeak to assess occupational noise exposure near the ear. The device records continuous, intermittent, and impulsive sounds over a one-second logging interval, utilising frequency weightings (A, C, Z) and time weightings (Fast, Slow, Impulse). While compliance presets include OSHA (5-dB exchange rate) and NIOSH (3-dB exchange rate), profiles for the Control of Noise at Work Regulations 2005 (implementing EU Directive 2003/10/EC) are available for UK reporting.
Core components—comprising the microphone, signal processor, and display—acquire and store data within a typical range of 55–140 dB(A). These instruments are widely used in sectors such as manufacturing, construction, and oil & gas to demonstrate compliance with OSHA 29 CFR 1910.95 and NIOSH standards, and to map results to BS EN ISO 9612 and the Control of Noise at Work Regulations 2005. This data is essential for preventing Noise-Induced Hearing Loss (NIHL) by comparing exposure levels against legal action limits.
Operational characteristics typically include a rechargeable battery life exceeding 40 hours, 8 GB of memory, and IP65 ingress protection. The device operates within a temperature range of −10 °C to +50 °C and supports data export via USB or wireless connections. An intrinsically safe option is available for hazardous environments. Field calibration, using an acoustic calibrator compliant with BS EN IEC 60942, is mandatory before and after each survey to ensure accuracy.
While both instruments measure sound, they serve distinct compliance requirements. A noise dosimeter (BS EN 61252) is a wearable device positioned on the shoulder or collar to capture a worker’s personal exposure as they move between sources. It logs data over a full shift (e.g., 8–12 hours) and reports parameters such as LAeq,T, LEX,8h (TWA), dose %, and LZpeak/LCpeak, adhering to specific protocols like OSHA, NIOSH, or the UK Control of Noise at Work Regulations.
An integrating sound level meter (SLM) (BS EN 61672-1 Class 1/2) is typically handheld or mounted on a tripod for area or source measurements—such as spot checks, task noise profiling, or engineering control assessments. Although modern integrating SLMs can log time histories, they measure noise at a specific location rather than in the immediate vicinity of the ear.
Both devices manage a wide dynamic range, including impulsive noise; dosimeters and SLMs commonly measure peaks up to approximately 140 dB (Z/C-peak). The primary distinction lies in the method of assessment: wearable, near-ear personal exposure (dosimeter) versus fixed-point location assessment (SLM).
For continuous workplace noise monitoring, a noise dosimeter such as the SV 104A is preferred, as it measures actual exposure throughout a shift, aiding in the prevention of noise-induced hearing loss. Handheld sound level meters are generally utilised for shorter measurements of single noise sources and are less suited for comprehensive personal exposure assessments.
International standards and local law regulations regulate noise dosimeter use. Therefore, the choice of the best device depends on meeting the requirements:
| UK & Europe | |
| BS EN 61252 | Specifies the performance and testing requirements for personal sound exposure meters to accurately measure sound and protect workers’ hearing. |
| BS ISO 1999 | Provides guidelines for estimating noise-induced hearing loss based on exposure duration. |
| BS EN ISO 9612 | Details engineering methods for determining occupational noise exposure and evaluating noise levels in the workplace. |
| Control of Noise at Work Regulations 2005 (implementing EU Directive 2003/10/EC) | Establishes exposure limit values and action levels for workplace noise, ensuring the protection of hearing across various industries. |
| United States | |
| ANSI S1.25-1991 (R2020) | Specifies performance criteria for personal noise dosimeters to ensure consistency in noise monitoring and measurement. |
| OSHA 29 CFR 1910.95 | Enforces occupational noise exposure regulations, setting permissible exposure limits (PEL) for workplace noise levels. |
| MSHA 30 CFR Part 62 | Regulates occupational noise exposure standards specifically for mines to protect miners from hearing loss caused by excessive noise. |
| ACGIH TLVs for Noise | Publishes recommended Threshold Limit Values (TLVs) for noise exposure in various occupational environments. |
The functional specifications of noise dosimeters under BS EN 61252 are broadly equivalent to those mandated by ANSI S1.25-1991 (R2020) in the United States. Whilst variations in terminology and specific criteria exist, both standards ensure that personal noise dosimeters satisfy rigorous performance requirements:
| Feature | Functionality |
|---|---|
| Microphone, Signal Processor, and Display | Comprises a microphone, signal processor, and display to present real-time measurement results. |
| Frequency Weighting | Measures both A-weighted and C-weighted sound levels in accordance with BS EN 61672-1 for accurate noise risk assessment. |
| Measurement Indicators |
|
| Noise Measurement Range | Spans a range from 70 dB to 137 dB for A-weighted sound pressure levels, with peak measurements up to 140 dB. |
| 8-hour Leq | Quantifies the 8-hour A-weighted equivalent continuous sound level (LAeq,8h), essential for assessing daily personal noise dose per BS ISO 1999 and the Control of Noise at Work Regulations. |
| Noise Criterion (Dose) | Calculates and displays the percentage criterion sound exposure (dose), reflecting actual exposure relative to the limit. Displays the corresponding criterion sound level and duration, supporting 3 dB, 4 dB, or 5 dB exchange rates. |
| Exchange Rate | Accommodates exchange rates of 3 dB, 4 dB, or 5 dB for calculating percentage noise dose, enabling accurate interpretation of exposure levels across varying durations. |
| Calibration | Facilitates both acoustic and electrical calibration. Includes sensitivity adjustment via a sound calibrator to ensure accuracy across the frequency range. |
| Display | Features a physical display or storage system to present or record measurement results. Simple output connections are insufficient. |
| Marking | Labelled with the BS EN 61252 standard number, manufacturer name, model designation, serial number, and compatible battery types (where user-replaceable). |
| Environmental Requirements | Conforms to Class 2 sound level meter requirements for static pressure, temperature, and humidity, as defined in BS EN 61672-1:2013. |
Octave band analysis is essential in factory noise monitoring as it enables the assessment of low- and high-frequency noise components. By decomposing noise into specific frequency bands, one can identify the dominant frequencies. This capability is particularly useful for isolating specific noise sources and detecting extraneous sounds (e.g., those unrelated to typical machinery operation) that might interfere with accurate assessments.
Regarding high-frequency noise, octave band analysis is critical for the selection of appropriate hearing protection, as stipulated by BS EN ISO 4869-2. This data ensures that hearing protection is effectively tailored to attenuate the most harmful frequencies, thereby safeguarding workers’ hearing.
In the industrial hygiene market, three main manufacturers offer professional dosimeters that adhere to both ANSI and IEC standards:
| Manufacturer | Features/Description |
|---|---|
| SVANTEK | A leading European brand offering IEC type-approved noise dosimeters, including intrinsically safe versions for hazardous environments. |
| TSI | A US-based company that acquired the Quest and Casella brands, holding a prominent position in the American market. They provide both standard and intrinsically safe dosimeters. |
| Cirrus | A UK-based company offering both standard and intrinsically safe noise dosimeters, renowned for their quality and reliability. |
There is no single “best” instrument for every site; the appropriate choice depends on the specific regulatory environment and programme requirements. For compliance with the UK Control of Noise at Work Regulations 2005 (or US NIOSH standards), select a wearable dosimeter (BS EN 61252) that logs a full shift and supports a 3 dB exchange rate with appropriate action values (e.g., 80 dB and 85 dB). Conversely, US OSHA compliance requires a 5 dB exchange rate. The device should record near-ear parameters such as LAeq,T, LEX,8h (TWA), dose %, and LZpeak/LCpeak.
Key features to consider: Look for multiple virtual dosimeter profiles (to measure HSE and OSHA standards simultaneously), high-peak handling (~140 dB Z/C-peak), and a battery life ≥40 hours for multi-day assessments. Essential functionalities include 1-second logging, Bluetooth connectivity with a mobile app for setup and verification, secure data export, motion/vibration detection (to identify tampering or removal), and optional audio recording or octave band analysis for source identification. For hazardous areas, ensure the model is intrinsically safe (ATEX/IECEx/UKEX).
Several reputable product families meet these criteria, offering wireless capability, extended runtime, and advanced diagnostics. Shortlisting based on your regulatory regime, intrinsic safety (IS) requirements, and reporting workflow will determine the optimal choice for your hearing conservation programme.
Representative options (alphabetical):
Note: These are representative, credible options. The “best” solution depends on specific constraints such as IS certification, software preferences, diagnostic needs, budget, and service availability.
Why the SV 104 noise dosimeter is considered a market leader: Early designs in the SV 104 series helped popularise a robust feature set—including durable MEMS microphones, automated audio/event capture, motion/vibration wear detection, and onboard frequency analysis—that many current models now emulate. Utilising these capabilities improves data integrity and verifies that the equipment is being worn correctly.
Noise dosimeters are utilised for both crew-worn and static acoustic measurements on the ISS to assess and manage personal noise exposure.
ISS operations rely on dosimeters for near-ear exposure monitoring and static mapping. SVANTEK’s wearable technology (e.g., the SV 104A and SV 102A+) has been applied in both the baseline monitoring programme and the AX-4 Wireless Acoustics research to explore wireless, crew-worn methodologies.
Calibration ensures that a noise dosimeter provides accurate and reliable measurements of noise. Over time, environmental factors like temperature, humidity, and regular usage can cause the device to drift from its true values. Calibration aligns the dosimeter’s readings with a known standard, ensuring that the data collected is precise and consistent with regulatory requirements.
Regular verification (often before and after each measurement session) is essential to ensure that the dosimeter continues to provide accurate decibel readings for worker’s exposure assessments, helping ensure regulatory compliance and the protection of workers from excessive noise.
| Factor | Description |
|---|---|
| Calibration | Regular calibration is essential to ensure accurate readings and maintain the dosimeter’s reliability and consistency. |
| Humidity | Extreme humidity levels can affect microphone sensitivity, potentially leading to fluctuations and measurement inaccuracies. |
| Temperature | Extreme temperatures can impair the performance of the dosimeter, affecting both the accuracy and precision of noise measurements. |
| Microphone Type and Placement | Correct microphone selection and positioning are crucial for capturing accurate noise levels without interference. |
| Background Noise | Ambient noise and wind can interfere with measurements, reducing precision and distorting results. |
| Time and Frequency Weighting | Incorrect time and frequency weighting settings can result in inaccurate noise exposure assessments. |
| Impulse Noise | Sudden, high-intensity noises require a rapid dosimeter response to ensure accurate capture. |
| Wear and Tear | Damaged or worn components can compromise accuracy, necessitating regular maintenance. |
To analyse noise results, first collect data using a noise dosimeter with data logging capabilities. Once collected, download the data to the manufacturer’s software. This software enables the processing of noise data, including metrics such as LAeq,8h and TWA. By importing the data files, you can commence the analysis process.
With the data imported, you can use the software to analyze for peaks and other critical noise metrics. The software allows you to review time-stamped audio recordings, helping you identify and exclude unwanted sounds, and ensuring more accurate analysis. This process is essential for determining compliance with noise exposure limits and generating detailed reports.
| Feature | US (OSHA Limits) | EU (Directive 2003/10/EC) |
|---|---|---|
| Exchange Rate | 5 dB: The allowable exposure time is halved for every 5 dB increase in noise level. | 3 dB: The allowable exposure time is halved for every 3 dB increase in noise level. |
| Exposure Limit | Permissible Exposure Limit (PEL): 90 dB(A) (8-hour TWA). Example: 8 hours at 90 dB(A), or 4 hours at 95 dB(A). |
Exposure Limit Value (ELV):
|
| Action Levels | Action Level: 85 dB(A) (8-hour TWA). At or above this level, employers must implement a hearing conservation programme. |
Upper Exposure Action Values:
|
| Peak Level Definition | 140 dB(C): Denotes the true peak level, measuring the highest instantaneous noise pressure. | Exposure Limit Value: 140 dB(C). Action Values:
|
| Workplace Environment | Noise Levels (dB) | Description |
|---|---|---|
| Offices | 50–60 dB | Background noise generated by computers, printers, and general conversation. |
| Retail & Hospitality | 60–75 dB | Customer activity, background music, and equipment noise. |
| Factories & Manufacturing | 80–100 dB | Noise from machinery, conveyors, and tooling; hearing protection is often required. |
| Construction Sites | 85–120 dB | Heavy plant and machinery, such as breakers and pneumatic drills. |
| Airports | 100–140 dB | Aircraft noise during taxiing, takeoff, and landing; high-grade hearing protection is mandatory. |
| Mining | 90–115 dB | Drilling, blasting, and heavy equipment operations; hearing protection is mandatory. |
| Concerts & Nightclubs | 95–110 dB | Amplified music; hazardous for prolonged exposure without protection. |
| Emergency Services | 100–115 dB | High-intensity noise from sirens and alarms. |
| Agriculture | 85–100 dB | Noise from tractors and heavy farm machinery; hearing protection is required. |
In factories, construction sites, and mining operations, there are often high-impulse noises (sudden, short bursts of sound), such as those from metal stamping, hammering, or explosions. These impulse noises can exceed 140 dB and are particularly dangerous because they can cause immediate hearing damage, even with short exposure.
| Impulse Noise Source | Noise Levels (dB) | Description |
|---|---|---|
| Metal Stamping/Pressing | Up to 150 dB | Rapid, high-intensity impact noise generated by metalworking presses. |
| Pneumatic Tools | 120–140 dB | Percussive noise emitted by pneumatic drills, breakers, and impact wrenches. |
| Explosions/Blasting (Mining) | Exceeding 140 dB | High-energy impulsive noise resulting from detonation and blasting activities. |
| Health Effect | Description |
|---|---|
| Noise-Induced Hearing Loss (NIHL) | Permanent damage to the sensitive structures of the inner ear, resulting in irreversible hearing impairment. |
| Tinnitus | A persistent ringing, buzzing, or humming sensation in the ears, frequently associated with hearing loss. |
| Cardiovascular Issues | Heightened risk of hypertension (high blood pressure), ischaemic heart disease, and stroke due to physiological stress. |
| Sleep Disturbances | Disrupted sleep patterns, including insomnia and frequent waking, which contribute to chronic fatigue. |
| Cognitive Impairment | Reduced concentration, memory deficits, and impaired learning ability, affecting complex task performance. |
| Increased Stress and Anxiety | Chronic activation of the body’s stress response, manifesting as anxiety, irritability, and exhaustion. |
| Reduced Productivity | Impaired communication and an increased risk of workplace accidents, resulting in lower operational efficiency. |
| Balance Problems | Potential disruption of the vestibular system, which may cause dizziness or disorientation in high-noise environments. |
