Practical case studies of successful ways to reduce noise levels in the workplace.
The Control of Noise at Work Regulations 2005 say that the employer must reduce the noise risk by all other means 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 my noise assessments - not all of them are complex or cost a lot of money, but they were effective.
All the examples below are noise-reduction cases I have measured on noise assessments, 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.
Key points: Practical ways to reduce noise exposures
Some improvement is better than none, don’t let ‘perfect’ get in the way of ‘better’.
Hanging strip plastic curtains can reduce noise levels by 10 dB or more.
Changing air gun handles can reduce noise exposures from ≈112 dBA(A) to ≈89 dB(A), a huge improvement.
Partial enclosures or screens can stop other people being exposed to noises, leaving just the operator.
Relocating loud tools into separate work areas can dramatically reduce the number of people exposed to them.
Even old bits of carpet behind a guillotine can eliminate a lot of the crashing impact noise.
Different brands of the same type of tool can make a big difference to noise levels.
Swapping people between jobs at lunchtime can take average exposures back below the daily limits.
A 3 dB(A) change doubles or halves your noise risk
Before looking at practical examples of noise control, it is worth highlighting the principle 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’s 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.
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.
Some noise attenuation is good, even if people still get bursts of quite high noise sometimes
The Noise Regs focus on the average noise exposure for people and not 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 use air guns and if so it is commonly in short bursts. Despite the short exposure time, the noise can be exceedingly high and enough to bring the daily averages over the limits. They could do work to reduce the air gun noise level (see below) and although it still remains over the limit it is now by a lot less than it was before and means the daily average for the user is now back below the limit.
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 a level as possible.
Recalculating noise exposures before or after taking remedial actions
If you wish to confirm average employee noise exposures, you can use this free noise exposure calculator tool where you can add both exposure durations and noise levels and it will work out a daily noise exposure. You change the dB levels to see what any impacts from remedial actions potentially are on daily exposures.
Fixed or mobile plastic screening
A standard plastic strip curtain
Commonly used around industry, the hanging plastic strip curtain can be very effective as a noise control measure. What I am referring to 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.
The impact of plastic curtains on noise levels
Welding bays and mobile plastic welding screens
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.
Pharmaceutical factory example
On a noise assessment, a site had the small bottle filling machines on one side of a hanging curtain, then the boxing and packing areas on the other side.
The curtain was the standard transparent strip curtain, in this case quite a thing gauge one. On the filling side noise levels were 86 dB(A) from the fillers, while on the quieter side they were 81 dB(A) with that noise coming from the boxing machines. There was no more than 15cm between those two measurement positions.
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 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 of the noise assessment, one person was based all the day at each job, 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 reducing air gun noise
Air guns are a commonly used tool 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 key 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 some examples of actual measures taken to deal with air gun noise which I have come across in my noise assessments.
Example case: Replacing the air guns with low noise alternatives
A CNC site had air guns with noise levels between 102 and 112 dB(A) causing daily average noise levels to be into the 90 dB(A). 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 risk.
All the air guns were replaced with 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, the other impact was to remove all requirements 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 pay for themselves in the first year and then the company is continually saving money every year from then on.
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.
Example case: Shoe factory air gun noise reduction
A factory had air guns averaging 100 dB(A), a noise level where the daily limit would be reached in only 15 minutes of use.
They replaced the standard handle with a low-noise PCL one and the noise was now reduced to 86 dB(A). While still over the main limit, at 86 dB(A) it would now take six hours of use in a day to reach the limit, a huge improvement in noise safety.
Example case: 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.
Example case: Screw-on air gun silencers
Rather than changing the entire handle, you can fit screw-on silencers to the nozzles.
In this video, these are the same noise meters, with the same air gun handle, in exactly the same position, with exactly the same air supply.
Without the silencer the air gun is in the region of 112 to 113 dB(A), while with the silencer it becomes 95 to 97 dB(A).
While 97 dB(A) is still over the limit, the ‘safe use’ time has gone from 30 seconds of usage at 113 dB(A), to 30 minutes of usage at 97 dB(A). 30 seconds will easily be exceeded in a day, 30 minutes is less likely, a huge improvement in noise safety levels.
Physical separation of high noise jobs
Where space allows, locating higher noise equipment in a physically separate area can be a great noise control
Separate grinding room
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.
Moving a loud job outside
A client has a site where noise exposures were generally in the low 80s dB(A), but then had one job involving cutting steel beams with a large saw. It was not used often or for long periods but that saw was around 106 dB(A), a noise level which will reach the daily limit in about 3½ minutes, even with no other noise exposures in the day.
They put up an external covered area in their rear yard, basically a car port style structure with just a roof and a rear wall, and located the chop saw out there. That removed the higher noise risk entirely from all the rest of the employees in the production area.
As a further consequence, only the two or three people who may use that saw now fall into the requirement for both mandatory hearing protection, and from a cost perspective, also meant only two or three people needed ongoing hearing testing rather 30+ people. That more than paid for itself very quickly.
Separate cutting room
A client had mostly quiet jobs involving fitting plasterboard walls, electrical fittings and decorating, but also had a need for cutting wood to make the frames. As they had space outside, they created a separate cutting shed and located all the saws in there. Saws were typically around 96 dB(A), while the rest of the work averaged below the lower 80 dB(A) limit. Again, this dramatically reduced the number of peopel exposed to the noise.
Physical enclosures of machines or people
Rather than creating an entirely separate area, another route is to give physical enclosures. Most commonly they are around machines but can also be around people instead, creating operator cabins which are physically separated from higher noise areas.
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 Press 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 example
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.
Saw mill example
An operator of a large log saw (cutting up entire tree trunks into planks) spends most of his time at the controls. The company had built a wooden cabin around the control area. It was just wood and glass with no specialised acoustic materials.
Inside the cabin where he spends his time levels were 76 dB(A), while immediately outside the door noise levels were 87 dB(A), rising to the high 90s dB(C) closer to the saws. He still had a need to enter the main saw area occasionally but the cabin meant his daily exposure was now 83 dB(A) and below the main limit.
Screens rather than full enclosures
In the same saw mill, another saw operator had a simple perspex screen between him and the saws, so it was still open above and to the sides. This still had a beneficial impact on noise levels as levels just outside the screened area were 91 dB(A), while behind it they were 87 dB(A). The numbers sound like it is only a small change but that is more than halving his noise risk.
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.
Reducing impact noise
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 good 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.
Brewery kegging line example
As another example, this was a kegging line where the metal kegs tip over onto a chute and slide down onto a pallet.
The noise of the kegs hitting the chute is quite loud as it would be metal on metal, but two steps were taken to mitigate it.
The top surface of the metal chute has been lined to eliminate the metal-against-metal impact noise.
Below the chute, a spring has been added so the chute can move a little as the keg hits it, absorbing some of impact and again reducing the overall noise.
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.
Alternative tools to do the same job
When tools come up for replacement, choosing alternatives which can do the same job but with less noise is the ideal opportunity to reduce noise levels, and is in-keeping with the HSE’s push in L108 for employers to operate a ‘Buy Quiet’ programme.
Engineering site example - eliminating chop saws
A common tool in engineering is the humble chop saw used to cut down metal bars or sheets. Noise levels can be exceedingly high, commonly around 100 to 109 dB(A) depending on the metal being cut. At 109 dB(A) only two minutes of use in any day is enough to meet the daily exposure limits, even with no other noise at all. A significant noise risk.
At a small site in Selby they had replaced their chop saw with a small horizontal bandsaw and this made a massive difference to the noise levels, not only for the operator but also for anyone else in the vicinity of it when in use.
This bandsaw will cut the same metals, but instead of noise levels over 100 dB(A) this is now around 79 dB(A). A massive improvement in noise safety.
Vehicle workshop example - changing make of tool
I measured Milwaukee and DeWalt battery drills, both with the same wire brush attachment, and in the exact same position in the same workshop and found that the DeWalt has around four times less noise risk than the Milwaukee one. That is four times the noise risk for doing exactly the same job. Milwaukee 90 dB(A), DeWalt 83 dB(A). (For the noise people, 7 dB is indeed a bit more than four times the risk but I try to keep it as simple as possible).
Milwaukee are good, but that is quite a significant difference in the noise level.
As a side-note, this was not the only Milwaukee drill I tested, I did the same test with another drill in the same workshop and that was much louder still. I suspect that one had experienced a hard life and the motor was not as smooth as it once was and noise levels were ≈96 dB(A) in the same test situation. To be fair to Milwaukee I didn’t use that one in this comparison but it does show how keeping tools around for a long time can also impact on the noise levels.
Other engineering controls
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.
FAQ: Noise reduction and noise control measures
Are you sure a plastic strip curtain can reduce noise, it seems unlikely?
Yes, I have measured these many times over the years and there is always a drop in the noise levels on one side of the curtain compared to the other, assuming the main noise generation is on one side of it rather than coming from both sides.
Do I need special materials to reduce noise levels?
No, in a lot of the examples above they have operator cabins made out of wood, or saw enclosures made out of plywood, or just a standard plasterboard dividing wall. This is not to say that there is no place for special materials, just that you don’t always need to go down that route and sometimes a simple control works perfectly well.
If we use low-noise air guns then surely they will be too weak to do the job?
No, the low noise air guns do not reduce air pressure. Think of them as like a silencer on a gun, it still shoots, just more quietly.
Useful links for noise controls
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).
A contact there is Colin Forbes, on 0121 788 6503, or info@silvent.co.uk.
PCL - Low noise air gun handles
Their range includes some handles which are very effective at reducing noise levels.