A Guide to Using Sound Level Meters for Accurate Sound Measurements

Accurate sound level measurements are essential in work environments such as industrial facilities and commercial establishments to ensure people's safety and compliance with the Occupational Safety and Health Administration (OSHA) standards. According to the Center of Disease Control (CDC), 22 million workers in the US are exposed to damaging noise levels at their workplaces. Continuous exposure to loud noise can result in permanent hearing loss. OSHA requires employers to measure and implement hearing conservation programs in environments with high noise levels. This is only possible when you use the right sound level meter with proper guidelines. This meter produces reliable data that allows employers to design effective noise management strategies and comply with OSHA and other industry standards. This post discusses these sound level meters and offers insights on their usage, conditions to record, considerations for distance and positions, and tips for effective use of these devices indoors and outdoors. Stay tuned!

An Overview of Sound Level Meter

A sound level meter, commonly referred to as a sound meter or decibel meter, measures the volume of sound in a given environment. It features a calibrated microphone that can detect sound waves and convert them into electrical signals. The signals are displayed on the meter and offer real-time measurements of the sound level in any environment. These devices display sound level readings in decibels (dB).

Here are some general guidelines for accurate measurements using a sound level meter.

Choose the Right Device: This selection would depend on factors such as measurement range, accuracy, frequency range, and time weighting options (e.g., fast, slow).
Choose the Right Location:It is always better to choose a quiet environment for baseline measurements. The location must be free from extraneous noises such as HVAC systems, conversations or banter, vehicular traffic, and so on.
Calibrate the Meter:You must calibrate SLM according to the manufacturer's instructions before using it for measurement. Regular calibrations help provide accurate readings to a known reference level.
Set the Parameters of Measurement: Choose the frequency range (A-weighting for environmental noise, C-weighting for industrial noise), and response times.
Position the Sound Level Meter:Keep the sound level meter in an area away from obstacles that could reflect or obstruct sound waves. Always keep the microphone at the same height as the ears for accurate measurements. For instance, this can be around four to five feet above the ground for effective results.
Take Accurate Measurement:Activate SLM, hold it steady, and take measurements. You can record sound levels at various points, which would help you capture spatial variations in noise levels.
Maintain and Store Data:Store data for future reference and reporting.
Analyze and Interpret Results:You can review the recorded data to identify the noise sources, analyze trends, and assess compliance with OSHA and other industrial standards. This data will help you determine if further action is required.

Factors Affecting Sound Level Measurements

Here are some factors that can influence the accuracy of sound level measurements.

Background Noise:While conducting sound level measurements, it's important to consider the presence of background noise. This can affect the accuracy and reliability of the readings. To mitigate the influence of background noise, choose quiet environments whenever possible. Selecting locations away from industrial facilities, main roads, or other sources of significant noise can help reduce background noise levels and improve the accuracy of measurements.
Frequency Weighting:Frequency weighting is a crucial aspect of sound level measurement. Therefore, it is essential to determine the appropriate frequency weighting for a specific application. A-weighting and C-weighting are two popular frequency weightings, each serving different purposes based on the characteristics of the sound being measured. A-weighting is commonly used for measuring environmental noise, while C-weighting is suitable for industrial noise assessments.
Time Weighting:This is another important consideration when measuring a sound level meter. Based on the characteristics of the sound being measured, select the appropriate time weighting—fast or slow time weighting. Fast-time weighting can capture rapid changes in sound levels, while slow-time weighting provides a more averaged reading, smoothing out fluctuations in sound intensity.
Calibration:To maintain accuracy, SLM should be calibrated periodically according to the manufacturer's guidelines. This ensures that the device accurately measures sound levels relative to a known reference.

Things to Keep in Mind When Using Sound Level Meters Indoors and Outdoors

There are several things to consider while using these meters. The following pointers will help you understand the details.

Using a Sound Level Meter Indoors

Eliminating Obstacles:Minimize or remove obstacles that could block the path between the SLM microphone and the sound source, such as furniture, partitions, and other objects that may block or reflect sound waves. Ensure clear, unobstructed paths for sound transmission to capture accurate readings.
Proper Positioning of the Microphone:Position the SLM microphone at the same height as the listener's ears. This will accurately simulate human perception. For standing adults, this is around 4 to 5 feet (1.2 to 1.5 meters) above the ground. Aim the microphone directly towards the sound source to capture the most representative measurements.

Using a Sound Level Meter Outdoors

Weather Considerations:This is one of the most important considerations when using a sound level meter outdoors. Consider dry weather conditions for outdoor sound measurements as moisture can affect the performance of SLM and introduce measurement errors. Document weather conditions such as humidity, temperature, and atmospheric pressure as they can influence sound wave propagation.
Wind Protection:Wind introduces additional noise and affects sound measurements when used in open outdoor environments. To minimize the impact of wind on SLM's measurements, utilize wind protection measures to shield the microphone from wind-induced fluctuations. Employ wind shields designed for outdoor use
Measurement Adjustments in Windy Conditions: Adjust measurement settings or techniques to mitigate the effects of wind noise. If feasible, consider using wind screening or natural barriers to shield the measurement location from direct wind exposure.

These guidelines ensure accurate sound measurements both indoors and outdoors. This allows reliable assessment and management of noise levels in various environments.

If you require sound level meters for your next application, you must consult an industry player in this segment. Triplett stands different from its competitors. Over the years, the company has specialized in offering a wide range of sound level meters. These meters feature a microphone, signal processing, a preamplifier, and a display, which provides noise exposure parameters to prevent hearing hazards. The company’s digital sound level meters meet standards such as IEC 61672-1 type 2, IEC651 (Type 2), and ANSI S1.4 Type 2 with ±1.5dB, ±3.5dB@1kHz accuracy.