EXAMPLES OF WAYS TO REDUCE NOISE EXPOSURE LEVELS IN THE WORKPLACE
The Noise Regs say that hearing protection is a last resort and that the employer must exhaust all other means of reducing noise exposures first, before reaching for hearing protection.
That means there is a legal obligation on employers to reduce noise levels where reasonably practicable, even if it does not eliminate the noise completely. These are some examples of noise control measures I have come across during noise assessments - not all of them are overly complex or cost a lot of money, but they were effective.
You don’t have to make a dramatic difference in the dB numbers to make a significant improvement in the noise risk.
The HSE require employers to do something about reducing noise levels before reaching for the hearing protection, but what can be done practically can seem like something of a mystery.
Before diving into it, it is worth flagging up the old chestnut that 3 dB represents a doubling of the noise risk going up or a halving of the noise risk going down. What this means is that if you have a noise of 80 dB(A), then 83 dB(A) is twice as much noise, not 160 dB(A). The same is true going quieter, so 77 dB(A) is half the noise of 80 dB(A). The reason I stress this is that if you have a noise level of 95 dB(A) and you do some work and get it to 92 dB(A), don’t be disappointed and think ‘that is only 3 dB, it wasn’t worth the effort’. That 3 dB change has halved the risk of hearing damage for your staff working there and is a significant improvement.
The HSE give quite a lot of information in L108 about possible ways to reduce noise levels but sometimes it is more helpful to see real-world situations where it has been done. All the examples below therefore are noise-reduction cases I have actually measured, in real production environments, including just how much of a difference the actions made to noise exposure levels. I should stress that the number of decibels you may achieve could vary, but these show it can be done.
Some noise attenuation is good, even if people still get bursts of quite high noise sometimes
The Noise Regs are focused on the average noise exposure for people and not just occasional bursts above 85 dB(A), and a reduction of a few decibels in the highest noise parts of their job could mean they don’t need hearing protection at all, even if they still occasionally get a bit of noise exceeding 85 dB(A) for short times. I’m aware that can sound a bit opaque, so as examples of what I mean:
A site may reduce air gun noise (see below) significantly and although the air gun noise does remain over the limit it is now by a lot less than it did before. For the people, they don’t use an air gun continually all day, just in short bursts and their total exposure duration to that reduced-volume air gun noise is so short that the daily average now drops below the limits.
Enclosures around machines can mean someone spends most of their time separated from the noise. For short periods of setting up, etc. they do open the enclosure and get some bursts of the full noise, but for most of their day they are at a lower level and now do not meet the 85 dB(A) limit.
Doing this means the employer is compliant with the HSE’s Noise Regs, where they require average noise exposures to be reduced to as low as possible, even if still exceeding the upper limit.
How much difference does a reduction in decibels make to the noise risk?
The way noise is measured makes no logical sense to normal people as it is a logarithmic scale, meaning a small change in the number of decibels can equate to very significant changes in the noise risk. Think of noise as being like religion, it makes no sense if you actually think about it, just accept it and go with it!
A 3 dB reduction in noise levels is comparable to a halving of the noise risk.
A 6 dB reduction in noise is four times less noise risk.
A 9 dB reduction in noise is now around an eight times reduction in noise risk.
A 12 dB reduction in noise is now equivalent to a very significant 16 times reduction in noise risks.
The humble plastic strip curtain
Commonly used around industry, the plastic strip curtain can be very effective as a noise control measure. What I am talking about here is the simple translucent plastic hanging strip curtain which is often used to divide rooms in a factory.
I have measured many of these during noise assessments and typically they can give a reduction in the noise of anything from 10 to 14 dB, which given 3dB is a doubling of the noise energy, is quite a significant change.
On a noise assessment I measured levels of ≈73 dB(A) on one side of a curtain, and then it jumped immediately to ≈87 dB(A) on the other side.
The curtain is very effectively containing the noise and means one area can stay below the limits and no hearing protection is needed.
Partitioning a site with these doesn’t hinder passage of goods or personnel through them, but they are an effective and simple noise control measure. And cheap and cheap is always nice.
This video is a walk-though showing the live noise levels on either side of this plastic curtain.
Welding bays and plastic welding screens
The impact of plastic curtains on noise levels in a noise assessment
On a similar note to the strip curtains, welding bays are often separated by plastic screens, in this case to guard against eye injury from the arc. Usually, within these types of bays it is not so much the welding itself which makes a lot of noise but the associated occasional hammering and grinding, with the angle grinder often being used for quite prolonged times.
On a noise assessment in 2025 I had two welding bays, one in use and one immediately next to it which was not in use. The site had new heavy-gauge welding screens which went up to about head-height. When the grinding was taking place close to the plastic screen noise levels were ≈98 dB(A) for the person using the grinder but on the other side of the screen they immediately dropped to ≈80 dB(A), well below the 85 dB(A) limit. The two measurement positions were less than one metre apart, just separated by the screen.
Keeping those arc-protecting screens in good condition can have a very significant beneficial impact on noise, in this case very effectively keeping the noise risk contained to just the person doing the job rather than impacting more widely.
Plasterboard walls as a noise control
Another ‘it doesn’t have to be over-engineered to make a difference’ one is the standard plasterboard partition wall. By this I mean the normal build of a wooden frame (sometimes metal) with a 12mm plasterboard sheet on each side, insulation in the middle and then plastered. Basically the normal wall used in houses, etc.
On a noise assessment in 2025 I measured the noise in a production area where the production office was right among the noisy machinery.
Immediately outside the office noise levels were ≈80 dB(A).
Immediately inside the office with the door closed noise levels were ≈59 dB(A).
That plasterboard wall and office door were reducing noise levels by a good 20 dB(A).
Job rotation can also be very effective as a noise control
On a noise assessment in 2024 I came across a site which has an area of 86 dB(A), and another of 82 dB(A). At the time one person was based all the time in each, meaning one had a regular exposure of over the 85 dB(A) limit and one was under it.
As both jobs were similar I recommended that they use job rotation so each person did a maximum of 2 1/2 days on each. That gives them a weekly exposure of 84 dB(A), below the limit.
In a noise assessment, when assessing the typical noise exposures weekly limits are just as valid as the daily ones, so you can use this to manage a job rotation system, limiting the number of days someone spends on a higher noise job.
Air guns and air gun noise
Air guns are a commonly used tool in many industries and on noise assessments they can often be one of the main noise risks on a site, indeed in places such as CNC workshops the air guns can form the main noise risk.
Air guns typically cause noise of around 102 to even 111 or 112 dB(A) and at this level, only one to nine minutes of cumulative use in a day can be enough to make the operator’s daily average levels exceed the 85 dB(A) limit, even if there is no other noise exposure at all in the day. However, dealing with this can be an ‘easy win’ for the employer as there are ways to reduce the noise levels considerably.
Low noise air guns
Companies such as Silvent make a range of noise suppressors, ranging from swapping the entire air gun handle to the addition of silencers to the nozzles and these can be very effective, taking noise levels from over 100 dB(A) to the mid-to-high 80s dB(A), or even lower in some cases. What is important with noise is not just how loud it is but how long the exposure is. An unregulated air gun can hit the limits in just a few minutes of cumulative use in a day, even if there are no other noise exposures at all. A low-noise handle may still be around 89 dB(A) but now the ‘safe use time’ increases from a few minutes to around three hours, far more than most users will ever use it for in a day.
Such handles or silencers can reduce the noise considerably without reducing the effectiveness of the air gun - they can still do the job.
Reducing air pressures
This can be an effective control but care is needed. If done centrally on the compressed air system, will the lowered pressure still be enough for any other needs? Sometimes other tools need a minimum pressure and lowering the system pressure is not a viable alternative. Even where it is, chances are the pressure will get turned up again over time.
Reducing air pressure in the system can work but usually in specific circumstances, and ongoing management is needed to ensure it does not creep up again.
Air gun noise reduction practical examples
These are a couple of examples of measures taken to deal with air gun noise which I have come across in my noise assessments.
Case study 1: Replacing the air gun with low noise ones
On a noise assessment in summer 2025, a CNC site I measured had air guns generating noise levels of anything between 102 and 112 dB(A) causing operator daily average noise levels to be into the 90 dB(A), over the limits. The air guns are used for bursts at the end of each cycle, but they were so loud that even these short bursts were enough to cause a noise problem.
All the air guns were replaced with much lower noise alternatives from Silvent and they were now generating levels around 89 to 90 dB(A). While that is still over the limits it had taken the ‘safe use time’ from one minute at its worst and increased it to 2 1/2 hours which in reality is far more than the air guns are ever used for. As a direct result, the staff’s daily noise exposures had dropped from between 90 and 97 dB(A) to around 83 dB(A), eliminating the risks to their hearing.
There are also financial benefits to the employer. In this case they spent about £2,000 replacing all the air guns, quite a significant cost, but as well as taking away a significant noise risk to staff the other impact was to remove all the operators from the requirement for mandatory hearing testing. This will be a saving of over £2,000 not just once, but repeatedly, for years to come. The air guns therefore pay for themselves in the first year and then the company is continually quids-in every year from then on from this alone.
As well as the cost saving on health surveillance, as daily hearing protection is not needed there is another financial benefit there. A basic foam ear plug costs around 14p a day but with around 220 working days a year that equates to about £31 per year per person. For a 20 person workshop that saving is more around £600 a year, on top of the saving in hearing test costs.
That means even in Year 1 the employer is better off financially for having spent that £2,000 and the staff are better off as they have their health risk controlled and don’t need to wear hearing protection, which very few people like doing if they can help it.
Case study 2: Replacing the air guns with vacuum systems
A common use for air guns is to blow saws, etc. clear of debris. On a noise assessment in 2025 a joinery site had removed all the air guns for their CNCs and table saw and replaced them with a vacuum system - hand-held nozzles connected to the main extraction system. This had taken a noise level of around 102 dB(A) for the air guns and pretty much eliminated it completely as there was now no significant noise at all from the vacuum system. As another benefit, it had also eliminated the generation of a lot of airborne dust.
Creating a separate room just for noisy equipment can help
A client had a small grinding room in an otherwise quiet environment. A purpose-built simple wooden wall forming a room had been built around the grinders so all the grinding work was done in there - just one person and a couple of grinders so only a small space.
Inside the grinding room noise levels were ≈95 dB(A) while immediately outside the noise was ≈78 dB(A). as several staff were located in the quiet area immediately outside the grinding area this meant that only one person had a need for hearing protection and hearing testing, while all the others were now not only below the main 85 dB(A) limit but also the lower 80 dB(A) one.
A very effective but inexpensive solution.
Reducing impact noise on chutes and slides
This can also be quite cheap and yet very effective as a noise control. Sometimes a cheap n’dirty fix may not look elegant but can still be an effective way to reduce noise levels.
Not pretty, but effective - a lining reducing the constant clatter of parts falling onto the metal chute.
And how’s this for ‘basic but effective’, an old towel lining a table making a big reduction in impact noise.
As metal bars dropped onto the runners they had been lined with plastic - a huge difference to the noise levels.
Old carpet tiles and mats behind a guillotine - really cut down the crashing noise. Cheap but effective.
Silencers on ducting
On a previous noise assessment the levels in the corner of a factory were around 94 dB(A).
The factory fitted a silencer and on the next noise assessment in 2025 levels here were now 84 dB(A).
A 10 dB(A) is very significant and had taken the entire area back below the main noise limit.
Slings
Often finished parts drop into retaining areas before being taken away. On this site they had put slings in place which caught the metal tubes rather than have them clattering onto the floor.
Acoustic enclosures - enclosures around a machine
The are purpose-built enclosures which can be small and around a single machine or large covering huge things like printing presses.
The enclosure doesn’t have to be around the machine though, it could be around the person creating an operator cabin for staff who can stay in one place for at least part of their working routine.
Printing press example
I was on a site which had large printing presses, enormous room-sized things, and they had acoustic enclosures around them, separating the machine from the personnel. Levels inside the enclosure were averaging 91 dB(A), while outside it levels were ≈80 dB(A), even with the door open. Where the operator stood levels were more ≈78 dB(A), so below even the lower limit.
Punch Presses example
I’ve seen a few cases now where small presses are used to stamp out metal components and the client had put enclosures around them. Where the door is closed and the press running, inside the enclosure levels are ≈93 dB(A), while outside it more around 79 dB(A), effectively eliminating the noise risk for most of the working day.
Semi-enclosed bandsaw
Enclosures don’t always need to be fully enclosing the equipment. In this case the company had made their own enclosures for three sides of a bandsaw and it worked perfectly well.
The bandsaw operator was still over the limits but there were 10 to 12 staff working immediately behind the saw who were now out of any noise risk area.
Effectiveness of an enclosure around a small press stamping out metal parts. Video shows noise levels inside and outside the enclosure.
Acoustic enclosure around an individual press. Inside levels were 90 dB(A), while outside it they were ≈81 dB(A), even with the door open.
Useful links for noise control
Arcade UK - Acoustic enclosures
I have a few customers who swear by these people. They can design and build acoustic enclosures for anything and I have seen them used for enclosing massive printing presses or smaller plastic granulating machines. I am not sure if he is still there but the name Mike West gets spoken of almost reverently as a good chap to speak to.
Baxcrest - Acoustic enclosures
I have a client in Newbury who had used Baxcrest to make an acoustic enclosure for a machine there. Inside it the noise levels are around 95 dB(A), while immediately outside it the noise was 78 dB(A) - from way over the limits to nicely below them.
Noise-Tamer- Acoustic enclosures
These are the people who made the enclosures for the presses mentioned above and in that short video showing the change in noise levels achieved by the enclosures. Effectively knocked about 13 dB(A) or more off the noise. American company but have a base over here in Somerset.
Silvent - Low noise air guns and silencers
They have a range of air gun handles and nozzles and claim noise reductions even as far as the high-70s dB(A).