Controlling noise exposures

You've done your noise assessment and have come out with some people who are exceeding the 85dB(A) or 137 dB(C) noise exposure limits. Regulation 6 says you aren't allowed to hand out hearing protection unless you have made all reasonably practicable attempts to control noise risks by other means first. And handily Regulation 6 lays out what these attempts should be in order of a hierarchy - you must work down each step before landing at hearing protection.

In order of how the Noise Regs require it, the first job is to eliminate the noise at source, or if you can't eliminate it completely then the requirement is to reduce it as low as is reasonably practicable. So the first question is - can you eliminate the noise risk? If you can then great and you should do that, and if not then you need to reduce it by reasonably practicable means. Ah yes, that old 'reasonably practicable' chestnut again - so as low as you can get it, balancing the cost of remedial action against the benefits gained.

The second part of that goes on to say that where some noise risk remains you should then get the noise as low as reasonably practicable by organisational or technical means. This means an action plan, with realistic goals, including a timetable, for reducing noise levels and this should be part of your noise assessment. Indeed it is the whole point of doing the noise assessment really. There is a whole list of what these 'organisation or technical means' are which you need to look at to control noise. These are:

Other working methods to control noise

Put simply, can you do the job a different way so that it doesn't produce as much noise?

Choice of equipment for the least amount of noise

Usually more appropriate when buying new equipment, but when you are doing so, are there different options available and do some of these offer lower noise levels? They may cost a wee bit more but as long is that increased cost is in proportion to the improvement in the control of noise risk they give, then you should do it.

Design of the workplace for noise control

This can mean a range of things from construction materials used as cladding on the walls and/or roof to where you locate machinery and even things like position of loos and canteens. As some examples of what I'm waffling on about here:

  • In a double glazing factory there is always an area where aluminium reinforcement bars are cut which then sit inside the PVC frame. For the work flow it may make sense to locate this job centrally in the production area but the cutting of these bars is a very high noise task which can affect the whole workplace, many areas of which would otherwise be quiet. Welding the PVC frames is very quiet but often the workers there are exceeding the 85dB(A) limit because of the aluminium cutting in the centre of the production area. So can this high noise part be relocated to one side and screened, (even partially is better than nothing), rather than sitting centrally?
     
  • I have seen workplaces where people in quiet areas had to walk through very high noise areas to get to the loo and canteen meaning they became exposed. Became exposed to high noise that is, not that their trousers fell down. Can the workplace be redesigned so the need to walk through it is eliminated, or can acoustic screens be used to create a lower-noise corridor?

Reduction of noise by technical means

This could be by enclosures surrounding machinery, or complete or semi-enclosures around the operator position, or tunnels on exits from machines which help contain noise, lower noise materials such as nylon strips on conveyors rather than metal ones, low-noise flooring on metal loading ramps, etc. 

Maintenance programmes for minimising noise

An obvious thing here is maintenance jobs such as sharpening saw blades or replacing them - sharp blades make much less noise than blunt ones. Repairing motors where bearing are going. Keeping panels and guards fixed in place to prevent rattling. Using low-noise blades when they are being replaced. And so on. Staying on top of what can be fairly minor maintenance tasks can make a big difference to the noise generated. 

Limiting the duration of noise exposures

This covers other 'soft' options for limiting noise exposures whereby the person is removed from the environment rather than the environment's noise being reduced. This can be via things like job-rotation so people spend periods on quieter jobs as well as noisier ones rather than spending all day on high noise jobs, or ensuring that breaks are taken in quiet areas and people do not stay in the higher noise zones. By the way, there is a specific requirement that rest areas are low-noise.

In reality...

In reality you will end up with a combination of all of these. You may need to have hearing protection as it can be used immediately and used while some of the longer-term remedial measures are implemented. Or you may be able to have a couple of technical measures which reduce the levels a bit, and maybe a small amount of job rotation helping a little more, and hearing protection providing the final layer of defence. Some remedial measures may take a long time such as eliminating noise via newer low-noise machinery choices, but in the meantime some of smaller solutions will give some improvement.

Don't forget, the first goal is to eliminate, but after then it is to control the noise and reduce it as far as it is reasonably practicable to do so. This means that some improvement is better than none. Many times I've seen people getting caught up in looking for solutions which stop noise completely and ignoring the smaller part-solutions and end up doing nothing as they want the 'big fix'. These part-solutions, in combination, are the way which most workplaces go.

Ideally, look for technical controls over human controls. If you implement some new equipment or control noise via an enclosure for example, then it is there all the time and is benefitting everyone. If you control exposures by human controls such as arranging the work to limit time spent on higher noise jobs then sooner or later this will fall over - it needs ongoing management. Inevitably, at some point in time the reason why the job is being done that way will get forgotten and a way of working will come back which introduces higher noise exposures again.