T&M Noise Dosimetry: Understanding Noise Pollution and Measurement
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This article delves into the topic of noise pollution, providing an overview of noise dosimeter equipment and the process known as noise dosimetry (the measurement of noise radiation). We’ll explore benefits of noise dosimeter and will go through features of prominent noise dosimeters from various vendors.
Understanding Noise
The term “noise” generally refers to any unwanted sound energy produced by a vibrating body. Sound energies can be categorized into two types: audible and unaudible.
Audible sound falls within the frequency range of 20Hz to 20KHz. Sounds with frequencies below 20Hz are known as infrasonic, while those above 20,000 Hz (20KHz) are called ultrasonic.
Noise can be continuous or intermittent, and can also be classified as high frequency or low frequency. In any system, noise can be thought of as having three elements: the source, the transmission path, and the receiver.
Noise originates from various sources, including:
- Domestic: Mixers, utensil movement, etc.
- Commercial: Automobiles, planes, laboratories, etc.
- Industrial: Transport vehicles, generators, boilers, etc.
- Natural: Bird and animal calls, wind, sea tides, etc.
Noise Pollution and Control Techniques
While numerous sources contribute to noise, road traffic is often considered a primary source of noise pollution.
Noise levels are typically measured in decibels (dB) or A-weighted decibels (dB(A)), where dB(A) represents A-Weighted Sound Pressure Levels (SPL). Noise pollution occurs either at the source or along the transmission path before reaching the receiver.
Several techniques can be employed to control noise pollution:
- Reducing noise levels from domestic sources
- Regular maintenance of machines and automobiles
- Controlling vibrating devices
- Reducing sound emitted from loudspeakers
- Speaking in a low voice
Noise Level Measurement Equipment
The following table outlines various noise level measurement equipment and their specific functions:
| Noise level measurement equipment | Functional usage |
|---|---|
| Sound level meter (SLM) | Type-0: Lab reference standard, Type-1: Lab and field use in controlled environments, Type-2: General field use, Type-3: Noise survey |
| Impulse meters | Measures impulse noise levels, such as hammer blows |
| Frequency analyzers | Used with filters for design and analysis |
| Graphic recorders | Used with SLMs to plot SPL (Sound Pressure Level) over time |
| Noise dosimeter | (See detailed description below) |
| Calibrator | Checks the accuracy of SLMs |
3M Noise Dosimeter Specifications
Here are some specifications of the 3M noise dosimeter (e.g., model eg5-D):
- Easy USB connection with PC and Detection Management Software.
- Noise measurement range: 70 to 140 dB.
- Supports 5 independent noise dosimeters.
- Displays parameters: LAVG, LEQ, SPL, Dose, Min/Max levels, TWA, SEL, etc.
- Indicators: Battery, Dose exposure indicator
- Battery life: 40 hours.
- Meets ANSI S1.25, IEC61252, and other intrinsic safety standards.
Noise Dosimeter Vendors
The table below lists several noise dosimeter vendors and their products:
| Noise Dosimeter, company | Description |
|---|---|
| FLIR Systems India Pvt. Ltd. | Extech SL400, used to test noise exposure levels, supports USB interface, compact and light weight |
| Pulsar Instruments Plc. | doseBadge |
| 3M | Noise dosimeters used for noise dosimetry as mentioned above. |
| Noise Meters Inc. | Manufactures sound level meters, dosimeters, noise monitors and controllers, dust meters, vibration meters, etc. |
| Casella CEL Inc. | Models 350, 352 plus dosimeters and accessories |
Benefits of Noise dosimeter
Following are some of the advantages of noise dosimeter.
- Accurate Noise Exposure Measurement : Continuously measures and records sound levels over time to assess occupational noise exposure.
- Ensures Workplace Safety : Helps identify hazardous noise levels in industries like construction, manufacturing and aviation to prevent hearing loss.
- Compliance with Regulations : Aids in meeting occupational health standards such as OSHA, NIOSH and ISO noise exposure limits.
- Personalized Monitoring : Worn by workers to track individual noise exposure instead of relying on area based measurements.
- Data Logging & Reporting : Stores long term noise exposure data for analysis, documentation, and regulatory reporting.
- Early Detection of Noise Hazards : Helps implement preventive measures like hearing protection and noise control strategies.
- Portable & Easy to Use : Lightweight, wearable design allows for hands free monitoring without interfering with work activities.
- Supports Noise Control Planning : Assists employers in designing quieter work environments and selecting appropriate hearing protection devices.
Conclusion
A Noise Dosimeter is an essential tool for monitoring and managing occupational noise exposure, ensuring worker safety, regulatory compliance, and effective noise control. By providing real time and long term noise measurement, it helps industries prevent hearing damage, implement protective measures, and create safer work environments. Its portable and user friendly design makes it a valuable asset in health & safety management across various industries.
