The Latest in Noise, Sound and Vibration Monitoring

Shawcity has been a market leader in supplying instrumentation to the occupational health and safety industry for over forty years, and specialists in noise dosimetry since the early 1990s. While the basic concept is familiar to many, evolving technology means protection for workers is constantly developing and improving.

There are three methods for calculating hearing protection: (Read More)

 

Simplified Noise Reduction (SNR) which works over the entire perceptible frequency range i.e. reducing all noise by 10dB using Type 2 sound level meters or basic noise dosimetry.
High, Medium and Low Frequency Attenuation (HML) gives you a general attenuation across the frequency bands using newer dosimeters with a standard (C-A weighting) calculation.

Octave Band Analysis filters out problem frequencies while retaining the majority of the frequencies in the speaking zone (around 1-2kHz). This data is available in stand-alone sound level meters, which allows a level of protection on short term area surveys but not a true experience over long periods of time.  
Type 2 Personal Noise Dosimeters have recently come to the market and they offer unparalleled qualities in instruments of this size for individual use. Intrinsically Safe with capabilities for full octave band analysis, they enable users to tailor hearing protection to real day-to-day working environments.

Employees can utilize functions such as audio event recording and interrogation of real time data with app-based reporting. So you no longer need to wait until the end of a shift before downloading data to analyse it.

Cable-free, this type of instrument is typically attached close to the ear on the user’s shoulder and offer microphones with a dynamic range of 90 dB to measure noise from 60-140 dBA. Other advantages include TEDS memory and autocalibration, using commonly available acoustic calibrators. Docking stations handle battery charging while supporting PC data transfer through an IR interface. Rechargeable batteries can power devices for 50 hours.

The benefits of this new approach to personalised dosimeters underpin the simple fact that as an individual, the more effective and personalised your hearing protection is, the more likely you are to wear it which ultimately means better protection for the workforce.

Vibration management can also be a major issue for employers and employees as regular exposure to hand-arm vibration can cause a range of conditions known as Hand-Arm Vibration Syndrome (HAVS), which includes white finger and carpal tunnel syndrome. Similarly, whole body vibration can cause or aggravate back and other muscular pain.

This long-recognized potential hazard was legislated for in the Control of Vibration at Work Act 2005. Employers were given until 2010 to put together a management system to prevent and limit employee exposure, but the dominant issue became how to accurately and safely manage that exposure.

There are several opinions on how best to tackle the issue and prevent potentially life-altering - and highly litigious - conditions. The average claim for vibration-induced white finger is around £75,000, which reflects the severity of the condition for the employee and highlights the need for employers to find effective management solutions.

Initial assessment is sometimes a “smooth tool” policy. This uses the lowest vibration level tools available for the particular task, regardless of their capability to do the task. For example, you can purchase a tool with half the exposure level of your existing equipment but if it takes three times as long to complete the task you are potentially making the issue worse.

Using manufacturer data for vibration can often also be unreliable because there is no requirement to measure a tool in operation. If exposure is below the current Exposure Action Value (EAV) of 2.5m/s2 there is no requirement for declaration. For an employer it is almost impossible to use this information to monitor exposure management.

Databases of measured vibration levels for tools are available. These provide some good data with “real world” measurements of tools being used in common tasks of the correct model for your tool.  This can be good for some initial management goals, but it also has some major drawbacks as it doesn’t take into account the conditions of the specific application or tool.  The vibration magnitude of a tool can be greatly affected by its overall condition, for example the bearing or disc quality, or the particular task for which it’s being used.

This leads on to arguably the only realistic way of understanding tool exposure levels; measurement.  Vibration meters provide extremely accurate personalised data for specific tools used by individual employees in the specific application. The only true way of gauging and managing vibration exposure is to gain solid, measurable, repeatable data.

Over the last ten years vibration measurement has become standard practice across many industries and significant improvements have made in measurement technology, as well as affordability.  Consequently most employers now have a clearer understanding of their tool vibration risk and use this data in conjunction with a system such as the HSE Points guidelines to manage occupational exposure.
New instruments can now specifically focus on personal vibration measurement via a unit worn on the hand. These monitors measure real time vibration data logged over the course of an entire day.  They are true vibration meters which accurately measure an individual’s exposure from each tool and through each task.

Managing noise, sound and vibration exposure has now become an accurate and relatively straightforward task and effective worker protection against these hazards has finally become an affordable reality for every organisation.

Author: Alex Graft, Product Specialist Manager, Shawcity Ltd

Shawcity Ltd
www.shawcity.co.uk