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Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters

Safeguard Magazine

It’s Academic—Making noise visible

You can’t see sound, but you can see a label. WARWICK WILLIAMS describes a simple approach to raising awareness of noise exposure as a health hazard.

How many people does it take to produce a “noise label”? Well, not the actual label but rather to decide how to produce the label. To my consternation it takes many people, much talking, a long time, a lot of patience and constant revision. I’ll share the story.

It is well understood that constantly being exposed to loud noise, sound or music will result in those exposed acquiring a measurable hearing loss and difficulty understanding speech. As we are all different we will vary in the degree of loss and when it becomes significant to us, but before that time it may become significant to others: spouse, family and close friends: “I don’t have a hearing loss, you mumble”.

In many cases, prior to a measurable loss individuals will also experience “auditory processing” difficulties, typically when trying to follow conversations in background noise.

But back to the labels. Along with a colleague from the New South Wales WorkCover Authority, I felt it might be useful to label offensive noisy objects, as part of a process of raising the awareness of noise exposure in the workplace as a hearing health hazard. We were under no impression that this was an original thought – far from it. There are numerous New Zealand, Australian and International Standards and procedures that do a splendid job of detailing the methodology, instrumentation, test conditions and competence of the tester, all of which is very useful for acousticians. But how often do you see them used? Sadly these methods don’t have much presence in the workplace, where the main thrust of workplace health and safety is risk management, not noise measurement precision.

We decided we needed a simple measurement and labelling process for everyday use. In particular, a procedure suitable for small workplaces that cannot afford the luxury of a consultant. After much discussion between employer organisations, unions, regulators, consultants and others, an acceptable methodology was agreed. The detailed results of the discussions and implementation can be found in references 1 and 2 below. Given that discussions ranged from the problems of measuring machine guns to the difficulty of labelling the carpenter’s humble claw hammer, agreement was no mean feat.

The focus of the process centred on the availability of suitable sound level meters (SLM) available to carry out the measurement task considering the skills, knowledge and experience required for operation. It should be remembered that the idea is to implement a risk management tool, not a rigorous scientific assessment of noise emissions. To this end, with regards to the order of accuracy required and scope of the task, it was decided any Class 2/Type 2 SLM would be more than adequate.

As part of the project, an App named “Construction SLM” was also developed (reference 3). This particular App walks the user through the measurement process, produces a report, appropriate label and e-mails the report to the recipient of your choice.


  • • 
    Take four evenly spaced measurements around the operating plant or machine at a distance of 3m.
  • • 
    If there is an operator’s position then take a fifth measurement.
  • • 
    Select the highest of the five measurements and use it to select the appropriate label.

Notice the labels are simple: green for OK, red for Warning; rectangular and circular to facilitate easy recognition by those who are colour blind. There is no attempt to explain A-weighting and exposure times.

A before and after survey of workers in the construction and utilities sectors found that there was a definite effect after the introduction of the labels. People felt there was a greater awareness of noise from both management and worker perspectives.

While there may be criticism with this process, we should remember it is a risk management tool and fit for purpose. We do not need complexity. The main task of the noise label is not to specifically state how loud a device may be but to remind people to look after their hearing.

Earlier research has shown that the best way to maintain awareness is a simple message provided frequently. Remember, once you damage your hearing, it won’t come back!


National Acoustic Laboratories – NSW WorkCover Authority (2011) A practical guide for assessing noise generated by plant or equipment in the workplace.
Williams, W & Sukara, Z (2013) Simplified noise labelling, Journal of Health & Safety Research & Practice 5(2): 18 - 22, September, 2013
Kell, James (2012) Construction Sound Meter – an iPhone®, iPad®, iTouch® App

Warwick Williams PhD is senior research engineer in hearing loss prevention at the National Acoustic Laboratories within Macquarie University in New South Wales.

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