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How much is our hearing actually worth?

Noise

John Campbell and Martin Williams have investigated and written up their finding in this fantastic article about low-cost sound level meters and their claim to meet IEC61672.

It can be tempting to buy the cheapest tool for the job, especially if it claims to meet all the relevant requirements. But can these claims be trusted, should the buyer take these statements at face value or with a heavy pinch of salt?

Six low-cost sound level meters were randomly selected and tested at two independent, accredited ISO 17025 UKAS laboratories. All six meters failed at least one test, with a number failing multiple tests and basic requirements for providing the relevant information to perform a periodic test.

READ THE FULL ARTICLE BELOW

How much is our hearing actually worth may June2021 – Download PDF

In conclusion: All meters failed at least one test; some failed several tests, including linearity, frequency weighting and especially tone burst, which five of the six failed. One meter was close to passing all tests.

Acoustic Calibration Lab Testing

Each meter was advertised as being compliant with IEC 61672, which would indicate that they should meet the stringent requirements of this standard, and should pass all the tests detailed in part 3. Meters were purchased new, and immediately submitted to periodic testing per IEC61672-3, at two test laboratories. Four units failed to provide the required information in the user manual needed for a calibration check to be properly performed. In each case the manufacturer, upon request, was unable to provide the necessary information. One manufacturer did acknowledge the requirement and removed from their marketing, all claims to IEC61672.

According to the standard, testing should not normally be performed. However, for this exercise tests were made and failure of the manufacturer to provide compliance information meant that some of the tests were not accurate, as additional uncertainties were introduced. This is shown by some variance between individual calibration facilities. However, it is unlikely that the lack of this data would have resulted in failed tests becoming passes.

The results show that a low-cost meter is (as might be expected) capable of providing a noise level indication, but also that a number of instruments that claim IEC61672 compliance are not compliant. If an instrument is required for accurate noise measurements it is recommended that any claims of compliance are confirmed. This can be established by asking for evidence of type approval, typically in the form of a certificate from a national metrology institute, and not by just relying on the marketing of the sound level meter.

A procedure for the assessment of low frequency noise complaints – Salford University Guidance 2009

Noise

Application Note – Norsonic Measurements for A procedure for the assessment of low frequency noise complaints – Salford University Guidance 2009

Make sure your instrument is setup to make a 1/3 octave measurement each second.

Load your measurement into NorReview in the normal way.

Click the level versus time/ frequency display – Lf +Lt

You then see a split display of average levels for each second in top part of the screen and the frequency in the bottom.

Identify the recordings where the complainant has noted the low frequency noise is present. Listen to this recording and make sure it does not include people moving around the properties or transportation noise – The concept of the standard is for investigating mechanical/ industrial type noise sources. If the recording meets this criteria click on it to display the frequencies for this recording. For longer recordings which contain other noises you can highlight part of the recording and just display the frequencies for this.

The numbers are displayed on the right side of the screen – Click the Num Table tab. These can be copied and pasted into Excel. We are only interested in frequencies from 10Hz to 160Hz for this standard.

Table V from the standard:

In the example above the highest 1/3 octave is at 100Hz. The Average value at 100Hz is 49.2dB which is above the limit for the day and the night. Note if the noise under investigation is impulsive and not constant you can apply a 5dB penalty to the measured values.

The next stage of the assessment is to view this frequency over time to see if it has correlation with the complainant’s log/ diary sheet.

The example (from the office) shows repetitive presence of 100Hz tone which correlates with the recordings.

If there is a correlation you may wish to try and find the source of the noise. This is not always easy as low frequency noise is harder to pinpoint and identify. The third octave measurements can help you identify/ locate the source and it is sometimes useful to have the FFT module in your meter which gives a more detailed ‘acoustic fingerprint’ of the noise making it easier to locate sources where the acoustic environment is more complex.

Please contact Campbell Associates support@campbell-associates.co.uk with any questions.

Salford University Low Frequency Guide

How advanced fence line monitoring solutions at industrial sites can enhance community trust

Air Quality & Dust

In the industrial sector, maintaining compliance with environmental regulations and maintaining positive relationships with the surrounding community are essential. One of the most effective

Fenceline monitor

ways to achieve these goals is through robust fenceline (boundary) monitoring systems.

These systems not only help address regulatory requirements and community complaints but also demonstrate a commitment to environmental stewardship.

Our advanced fenceline monitoring solutions offer comprehensive air and noise quality monitoring, cloud-based data reporting, and automated alerts, ensuring that your facility operates transparently and responsibly.

Why Fenceline Monitoring Matters

Fenceline monitoring involves placing sensors along the boundary of an industrial site to continuously measure air and noise quality. This proactive approach helps detect and address potential issues before they become significant problems. Here’s why fenceline monitoring is crucial:

  • Regulatory Compliance: Environmental regulations are stringent, and non-compliance can result in hefty fines and damage to reputations. Fenceline monitoring ensures that your facility meets all required air quality standards, reducing the risk of violations.
  • Community Trust: Nearby communities are often concerned about the impact of industrial activities on their health and environment. Transparent monitoring and reporting help build trust, showing that your facility is committed to minimising its environmental footprint.
  • Complaint Management: Timely and reliable data allows for quick investigation and resolution of air quality and noise complaints from the community, improving relations and reducing conflict.

Features of Our Fenceline Monitoring Solutions

Fenceline noise monitor
  • Comprehensive Air and Noise Quality Monitoring: Our systems are equipped with state-of-the-art sensors that detect a wide range of air pollutants, including VOCs, , NO2, and PM. Additionally, integrated noise monitors capture real-time sound levels, providing a complete picture of environmental conditions.
  • Cloud-Based Data Reporting: Data from all sensors are transmitted to a secure cloud interface, making it easily accessible in real-time. Site managers and environmental health teams can view up-to-date information from anywhere.
  • Automated Reporting: Our cloud platform generates automated reports. This feature simplifies the monitoring and automates the data reviewing process.
  • Instant Alerts: With SMS and email alerts, you are immediately notified if pollutant levels or noise exceed predefined thresholds. This prompt notification system allows for swift action to mitigate any issues.

In an age where environmental responsibility is not just preferred but expected, investing in advanced fenceline monitoring systems is a smart choice for any industrial facility. Our comprehensive monitoring solutions provide accurate, real-time data on air and noise quality, ensuring regulatory compliance, addressing community complaints, and enhancing overall operational efficiency.

Experience the benefits of transparent, efficient, and proactive environmental management. Contact us today to learn more about how our solutions can help your facility achieve its environmental goals.

Campbell Associates Partner With Larson Davis

Noise

For 25 years, Campbell Associates has been dedicated to delivering exceptional service and top-quality products to our customers. In our continued commitment to meeting your needs, we are thrilled to announce our new partnership with Larson Davis.

This collaboration allows us to offer an expanded range of premium products at competitive prices, further enhancing the value we provide to you.

Larson Davis (LD) was founded in 1981, as a manufacturer of precision acoustic test and vibration measurement instrumentation. In 1999, Larson Davis became a division of the industry leader PCB Group, PCB Piezotronics, Inc.

With a range of acoustic and vibration equipment to serve all types of applications, Larson Davis monitors offer a premium experience at smart prices.

The SoundExpert® 821 is ergonomic & lightweight and offers users 40 hours of battery life! With USB and wireless charging you will never need to worry about power.

The SoundAdvisor™ 831 offers users a class 1 sound level meter with USB power & WiFi connection.

Campbell Associates are excited to partner with a company who is constantly innovating and expanding their product range to fulfil customers needs.