Monthly Archives: April 2015

Control of Noise at Work – It’s Not Just Red Tape

The Control of Noise at Work Regulations were introduced to protect the hearing of employees in the workplace, but is it just more red tape?


The ear is an amazing instrument, able to distinguish the most subtle of sounds and also deal with very high sound pressure levels. Inside the ear is a small snail-shaped structure – the Cochlea, which is filled with fluid and thousands of minute hair cells. When sound is received by the ear, these hair cells vibrate at different frequencies and tell our brain what we are hearing. It’s a very clever device.


If we are exposed to excessive noise, some of these tiny hair cells can become damaged, and even die completely. The hair cells do not re-grow and we lose the ability to hear those frequencies properly for the rest of our lives. The most commonly affected frequencies by exposure to excessive noise are those at the upper end of the speech range; the ‘pssh, tsss,’ type noises that we use to identify words.


The effect on life can be detrimental – sufferers of noise induced hearing loss often find that when in a social situation they can appreciate the atmosphere, background music and that their friends are talking, but find it almost impossible to tell what they are saying. The difficulty in understanding speech, especially in noisy situations, can have a real negative effect on an individual’s life and wellbeing – and this hearing loss is something that cannot be rectified, but can be prevented. By the time you realise that something isn’t right, it’s too late.


Sometimes when the hair cells become damaged and no longer send the correct signals to the brain, we struggle to hear those frequencies and the brain replaces the expected signals with a constant noise. This manifests itself as a dull ringing in the ears, known as Tinnitus. The ringing in the ears can be sporadic or present all of the time, day and night. It can be loud or quiet, with gradual or sudden onset, but it is inescapable. There are treatments that can help alleviate the symptoms a little, but there is no cure. Tinnitus is perhaps the most unpleasant condition to arise from overexposure to noise in the workplace and there have even been instances of suicide linked to the condition.


Hearing damage from overexposure to noise is something that you do not want.
Fortunately, adherence to the Control of Noise at Work Regulations means that this hearing damage should be avoided. The Regulations stipulate that employers undertake a noise at work assessment where activities are of a noisy nature to quantify their employees exposure; this is usually done using hand held sound level meters and small Dosebadges or dosemeters that clip onto employees clothing during an assessment. The disruption to the normal working operation is therefore minimal.


If it is found that the noise environment is above those recommended in the Regulations (Action Values), there are steps that employers must take to safeguard their employees hearing. These include reducing the noise levels at source if practicable, enforcing the use of suitable hearing protection in appropriate areas, and having their employees hearing tested. The result is that the hearing of employees is better protected, and employers can be satisfied that they have taken steps to limit noise exposure.


Many ANC member companies can offer full noise at work assessments, advice on hearing protection and practicable remedial measures, as well as the audiometric (hearing) tests for employees.

BS 4142:2014 – The change from a Numbers Game to a Reasoned Argument?

As the industry standard for assessing industrial and commercial sound, to say BS 4142 has a wide reach would be an understatement. With fundamental changes in the approach taken by the standard, it’s worth considering the impact this will have on those who carry out the assessments, those required to review them, and those that need them.


The latest revision to BS 4142 is a substantive rewrite of the standard, and to go into all the various changes would require a much longer article than this. Instead I want to look at what is probably the most fundamental change – the change from a conclusion based on some simple arithmetic, to contexts, uncertainties, and the reliance on knowledge and experience.


In my mind, BS 4142:1997 was about whether the difference between two numbers met the target. If it did, great; if not, mitigation needed to be explored to achieve the target difference. The 2014 revision, however, takes a different approach. A range of differences are likely to be calculated, the uncertainty present in the differences needs to be considered, and whether the differences are significant or not depends on the context.
To deal with this, throughout the process the assessor is required to rely on their experience and knowledge (both of their discipline, and the project in hand) to decide what is appropriate, and justify this to be the case. This ranges from determination of representative background noise levels, to the range of corrections for character now available when calculating the rating level. In fact, the emphasis is placed so heavily on the abilities of the assessor, it is now required that they state in the report why they believe they are competent to carry it out in the first place.
As there are a number of decisions to be made along the way, I envisage a much greater level of cooperation between the assessor and recipient as being essential. This will obviously make for an interesting situation when there are multiple interested parties. It may be that resources could be developed in the future to help add a degree of uniformity to the process, such as databases of sources, case studies to illustrate the effect of context etc.
Anything of that nature is clearly some way off, and in the meantime it will be interesting to see how the industry responds to the changes. Generally speaking, people aren’t always enthusiastic at the prospect of change, and I expect the new approach is likely to divide opinion. There will always be naysayers in every walk of life, but it’s my hope that the vast majority of us will see this as an opportunity for an improved process and rise to the challenge.
For those looking for more information, there is a good article in the Institute of Acoustics Bulletin Jan/Feb 2015 under the Technical Contributions section that goes into the background and changes in a lot greater detail. This is definitely worth a read, depending on your context.