New Levels

The main thrust of this new law is to lower the acceptable levels of noise exposure, above which both employers and employees are required to take certain actions (see figure 3).

The first point to note is that there are 6 levels to monitor in the draft regulations compared with 3 in the 1989 version. It is also clear that the action levels have been reduced by 5dB each. Decibels are logarithmic and don’t work like normal numbers so this 5dB reduction actually equates in real terms to a 68% lowering of the levels. This means that a process that only just meets the existing criteria, will have to be reduced in sound output terms by 68% to maintain compliance.

Limit Value

New to the world of noise at work assessments is the concept of an Exposure Limit Value, set at 87dB(A) Lep’d. This is in place such that no employee shall be exposed to this level or above under any circumstances! On the face of it, this seems a tough one to deal with, except that hearing protection can be taken into account (as described above) unlike the action values. What this does mean is that care should be taken in the assessment of which hearing protection to use and it might be wise not to use the SNR method for that reason.

Weekly Averaging Derogation

If workers are exposed to high levels of noise for only a small part of a week then, under the new regulations it may be possible to average the exposure they receive over the whole week. The final position on this will only be clear with the publication of the full regulations. Even then care should be used when applying this derogation that the exposure is truly over a short enough duration.

Hearing Protection Selection

To estimate the effectiveness of hearing protection, there are three available methods, which are described above. The draft regulations do make a change to this process, based on concerns by many that the 'real-world' performance of ear defenders is rarely as tested by the manufacturer.

For the SNR and HML methods of performance calculation, the regulations state that the effectiveness of the defender should be de-rated by 4dB. For SNR numbers, this means subtracting 4 from the value given on the data-sheet and for HML numbers, it means decreasing the predicted noise reduction (PNR) level by 4dB.

For Octave band assessments, the assumed protection should be de-rated by subtracting a further standard deviation from the mean performance data. These values can be found on the data-sheet from the manufacturer. Alternatively, 4dB can be added to the measured level.

When to Measure

It clearly states in the draft proposal that the focus should be on risk assessment and that measuring the actual sound levels may not be necessary. A number of ‘listening checks’ are given to allow employers to assess whether or not they might be above the Lower Action Value. The principle is that as long as employers are carrying out risk assessments and hearing conservation there will be a much reduced effect on the population from noise induced hearing loss. The justification for this approach is largely to abdicate smaller companies from the responsibility of having to carry out measurements themselves.

There is a problem, however, with not taking measurements and it is one that is recognised by many industry specialists. The problem occurs in producing evidence in defence of future civil claims. Without measurements, there is in practice, no defence leading to successful claims and huge potential costs. The reason this is not written into the regulations is that the HSE do not have a remit covering civil matters. In essence, to satisfy the HSE, a company may well not need to measure noise levels at all, but not doing so, could lead to a long-term nightmare in indefensible claims and spiralling costs. Many insurance companies are taking on board this issue.