We reduce fan noise using advanced technology and engineering solutions that often provide a much higher noise reduction than common methods such as an acoustic enclosure, sound barrier, silencer or screen. This means our solutions often solve industrial noise nuisance problems after other fan noise control methods have been tried, but failed to provide enough noise reduction.
Companies can also benefit from large cost savings by selecting our specialist fan noise control techniques instead of common solutions. Consequently, our noise abatement methods have proved highly popular, successfully reducing fan noise on numerous extractors, blowers and dust extraction systems for many industrial, commercial and manufacturing companies throughout the UK.
Example: Dust Extractor Fan Noise Reduction
As soon as a company installed two new dust extract fans outside their wood-working factory, local residents started to complain about the noise and asked for sound-proofing to be installed. The company fitted acoustic enclosures over the two fans at a cost of £6000. Noise nuisance complaints continued. The company then spent £8000 on a sound reducing screen. Still the complaints continued.
Then the company asked us how to reduce the fan noise. We designed an advanced cancelling solution to suppress the fan noise at source. This achieved such a large noise reduction that the fans could not even be heard at the nearest residential property. Complaints ceased immediately. Our solution cost a small fraction of the £14,000 that had been spent unnecessarily on the noise reducing enclosures and screen.
The attenuating performance of silencers is poor at low frequencies. This means that silencers / attenuators usually provide little sound reduction at low frequencies. This is a major problem for industrial fans because they usually produce a loud low frequency drone or hum. Because the human ear is especially sensitive to drones, hums and whines, these are a very common cause of noise nuisance. Our advanced fan noise cancelling methods are highly effective at all frequencies: low, medium and high, and can often attenuate low frequency fan drones, hums and high frequency whines by 20 - 30 dB.
Example: When faced with complaints about a loud and fluctuating low frequency fan drone that residents found highly annoying, a food company fitted a silencer. Complaints continued and residents said the noise was no quieter. We were then consulted. Using advanced technology, our solution reduced the fan drone by 27 dB, making it completely inaudible at the houses by day or night.
When deciding how to reduce fan noise, it is common for companies to waste large amounts of money by choosing ineffective solutions or by treating the wrong fan, blower or equipment. Sometimes companies apply noise reduction measures to all the equipment when it is only necessary to treat one item (at much lower cost). Often companies guess which item(s) are causing noise nuisance and because guesses are usually wrong, they spend substantial time and money on noise mitigation measures that provide little or no sound reduction.
Such wasted spending can be avoided by carrying out a diagnostic noise survey first, to establish beyond doubt which fan, blower, machine or equipment is the main noise source. In our surveys, we use very sophisticated noise measurement and analysis equipment coupled with considerable experience and expertise to identify precisely which fan or fans are causing the noise nuisance and how much sound reduction is needed for each. This enables the noise suppressing treatment to be tailored precisely, which can provide considerable cost savings.
After identifying which fans / blowers need treatment and how much sound reduction is necessary, we then carry out an assessment to determine the optimum solution in terms of noise reduction, cost and fan performance.
Example: Silence Fan for Bakery Bun Oven
An industrial bakery company started receiving noise nuisance complaints from several local residents about a very loud low frequency hum. The bakery identified their bun oven as the source and fitted a silencer to the combustion air fan to reduce the noise. This had no effect on the sound at the houses, so the bakery asked us how to reduce the fan noise. The oven has 11 fans. Using basic information about each fan and the Environmental Health Officer's frequency analysis of the sound, we identified the source of the hum within a few minutes.
The source was not the combustion fan to which the bakery had fitted a silencer, but two small cooling extractor fans. Our advanced solution was applied to reduce the fan noise - it was designed specifically to silence the fan hum. This was so successful that it made the oven extractor fans inaudible at the houses, even at night - reducing the low frequency fan hum by 27 dB (a huge sound reduction). There have been no noise nuisance complaints since. Residents were so relieved that the highly annoying hum was no longer audible that several wrote to thank us. Our solution had no effect on fan performance or bun oven cooling.
For a costing for reducing fan noise, click on contact us about fan sound control or ring 01727 864667.
To see more examples of how to reduce blower noise and the benefits of our high performance fan noise control solutions, continue reading.
Below are some more examples showing how to reduce fan noise and blower sound in a variety of industrial applications. Some are case studies where fans were causing noise nuisance to nearby residents (in some, noise abatement notices had been issued). Some are case studies of controlling fan noise for workers to comply with the Control of Noise at Work regulations. Many of the examples illustrate the major benefits that can result from using our engineering or advanced solutions to reduce fan noise, namely large cost savings and higher noise reductions than other sound attenuating methods.
Reducing Transport Fan Noise in a Food Factory
A company wanted to reduce workplace noise from an 'airveyor' system used to convey plastic bottles around a factory that manufactures product for the food industry. The conveying system uses a series of fans to transport the bottles. The company received a quote for £130,000 for acoustic enclosures to encase the conveying system. They then asked for our advice. We found the transport fans were the main noise source. Our small noise mitigation measures were applied to the fans, reducing the air conveyor noise by 6 dBA such that sound levels fell below the 85 dBA target. The total cost was about £2500, so our fan noise suppression solution achieved the desired noise reduction while saving the company about £127,000.
Paper Waste Extractor Fan Noise Abatement
A printing company wanted to reduce the noise from a paper waste extraction blower. The blower was annoying local residents who asked that a sound-proofing method be applied. The company installed an expensive acoustic enclosure around the blower, but noise nuisance complaints continued. They then asked us how to reduce the blower noise. We found that the problem was caused by a very loud and annoying low frequency tone ('hum') that emanated from the blower. We designed an engineering noise cancellation modification targeted specifically at suppressing the noise tone ('hum'). This was highly successful, achieving a 19 dB reduction in the noise tone such that it was no longer audible. Complaints stopped immediately. Had our solution been fitted first, it would have saved the company money because an acoustic enclosure would not have been needed.
Noise Control of Axial Fans for Machine Cooling
A manufacturing company wanted sound-proofing for a coater machine that was exposing workers to high sound levels within the factory. Our diagnostic survey found that the main noise source was a set of axial fans used for cooling the coater machine drier. We purpose-designed a small, compact silencer to suppress the fan sound. Our silencing solution was highly successful, reducing the axial fan noise by 14 dBA, to well below the 85 dBA limit stipulated in the regulations for noise levels at work. It cost considerably less than sound-proofing the entire coater machine.
Sound Reduction for Sawdust Extractor Fans
A sawdust waste extract system was causing noise nuisance to residents in a nearby housing estate. First, the company fitted a steel acoustic enclosure over the large main extractor fan, then a wooden fence beside the extraction system in an attempt to solve the noise problem. Complaints continued. Then the company asked us how to reduce the extractor fan noise.
Our diagnostic noise survey found that sound reducing measures were needed for both the large extract fan plus the small transfer fan. These centrifugal fans emitted a loud whine and hum, which were the cause of the nuisance problem. We designed an advanced engineering solution for both fans using noise cancelling methods. This noise suppressing treatment was very successful, reducing the whine from the large fan by 25 dB and the hum from the small transfer fan by 20 dB. This made both fans inaudible at the housing estate. Complaints ceased immediately.
Cleaning Fan Noise Control
We designed specialist muffling for a centrifugal blower that blows air onto the product to clean it. This silencing method was very successful, reducing the fan noise by 9 dBA. The resulting noise level was 81 - 82 dBA at nearby workers, well below the legal limit for noise at work. We also used advanced technology to design a noise cancellation modification to reduce a loud, highly annoying whine that was emitted by the blower. This achieved a massive 32 dB sound reduction, making the blower whine inaudible.
Scrubber Extractor Fan Noise Reduction
Following complaints from nearby residents about the noise from a smoke scrubbing extraction system, the company contacted the equipment supplier who fitted noise insulation muffling around the extractor fan. Complaints continued, so the company installed a tall fence around the fan and scrubber. Complaints continued, so we were asked how to reduce the blower noise. Our measurements showed that it was necessary to suppress the low frequency fan hum and also reduce the overall fan sound by at least 15 dBA. Our silencing solution achieved this and was so successful that it made the fan inaudible at the houses - in fact it could only be heard when standing close to the fan and scrubber.
Furnace Fume Extractor Fan Noise Control
A company wanted to reduce fan noise from a large industrial furnace fume extractor at a manufacturing factory. We designed sound-proofing measures using specialist sound-deadening materials that were applied to the exterior of the centrifugal fan casing. Our noise suppressing method lowered the sound by 12 dBA, which was more than sufficient to achieve the 85 dBA noise at work limit.
Reduce Fan Noise Hum at Sweets Manufacturing Factory
Nearby residents were being kept awake by a loud whine sound from an industrial extractor fan that expelled air to the exterior through the wall of a sweets manufacturing factory. Because the centrifugal fan operated all night, a very large sound reduction was needed. A standard silencer / attenuator would have been able to reduce the whine sound by only about 10 dB, which was nowhere near enough. So we designed a high performance silencer to be fitted to the ductwork exhaust. Our silencing method was highly successful, reducing the fan noise whine by a huge 25 dB such that the fan was no longer even audible at the nearest house. Our silencer was designed for very low airflow resistance as well as high noise attenuation and had negligible effect on the fan's extraction performance.
Attenuating Booth Extractor Fan
Small airflow noise mitigation measures were used to attenuate the sound from some booth extractor fans. These lowered the noise to 75 dBA (a 6 dBA sound attenuation), easily achieving the company's 80 dBA target for nearby workers. There were no installation costs - our solution merely required small adjustments to be made by the company's maintenance workers at negligible cost.
Attenuate Low Frequency Axial Fan Noise in Food Industry
A low frequency drone from several roof mounted extraction fans prompted complaints from nearby residents. The axial fans operate all day and night to provide cooling and ventilation in the food industry. Silencers could not be fitted into the ductwork to abate the cooling fan noise because they provide little sound attenuation at low frequencies - a standard silencer / attenuator would have provided only a 3 dB reduction, a barely detectable difference. Also, the hygiene requirements of the food industry meant the extraction system had to be cleaned with high pressure water jets. This would have soaked and damaged the noise absorbing material inside a silencer, making it even more ineffective.
We designed an engineering fan noise suppression solution to cancel out the drone sound. This provided a 19 dB reduction in the low frequency drone, making the cooling fans completely inaudible at the nearest house. As well as achieving 16 dB higher sound reduction, our solution cost less to install than a silencer. Because our fan noise cancelling modification was entirely made from steel, it could withstand high pressure water cleaning without being damaged and with no loss of sound reduction.
Silence Axial Fans - Attenuate Low Frequency Drone
A low frequency cooling fan drone (100 Hz) was causing nuisance to local residents at night. Normal silencers would have provided little noise attenuation at this low frequency. We designed noise mitigation modifications for the outlet duct. This converted the duct into a silencer, tailored to suppress the 100 Hz low frequency. This specialist silencing technique was very effective, reducing the low frequency fan noise drone by 14 dB such that it was inaudible to local residents - silence!
Waste Trim Fan Noise Control
A cardboard trim waste extract fan was exposing nearby workers to 89 dBA. The problem was solved by fitting a simple fan noise suppression solution to the intake of the existing ductwork. This silencing method achieved an 8 dBA noise reduction, lowering workers' noise levels to 81 dBA at very low cost.
Suppress Fan Noise Nuisance
A large, well-known UK manufacturer of white goods asked for our help after local residents started to complain about noise nuisance. Our diagnostic noise survey found the main cause of the annoyance was a pair of centrifugal extract fans, one large and one small. We designed an advanced engineering solution for cancelling the fan tones that were annoying the neighbours. This specialist technique managed to reduce the fan tones by 11 and 14 dB respectively. There were no further noise nuisance complaints.
Fan Noise Suppression by Maintenance
A company was considering fitting expensive sound-proofing to some extractor blowers when they discovered us and asked for our help. Using detailed narrow band frequency analysis, our diagnostic noise measurements showed that worn bearings were the cause of the high noise levels. Renewing the bearings reduced the sound from 87 dBA to 83 dBA, easily achieving the 85 dBA target for nearby workers - a very low cost fan noise control method !
Drier Extract Fan Sound Reduction
An industrial blower on a drier was causing noise nuisance and annoyance to local residents. Our diagnostic survey showed that the main cause of the nuisance was a loud low frequency drone from the blower, which residents found highly annoying. We designed an advanced sound abatement solution to cancel out the drone. This was highly successful, reducing the drone by a huge 22 dB with no loss of blower performance. Afterwards, the blower was inaudible at the houses.
Silence Extractor Fan at Very Low Cost
An industrial extract fan was exposing workers to 85 dBA. We were able to reduce the fan noise to 79 dBA with just a bucket of water - an extremely low cost noise control method!
Attenuation of Scrap Extraction Fan - Low Frequency Hum
A low frequency hum sound was annoying local residents. We used specialist survey equipment to measure the noise then analyse it. This showed that the source of the hum was a very large scrap extraction fan located outside the factory. A very high sound reduction was needed because the fan operates all night.
Our noise abatement solution used advanced technology to cancel out the fan hum, and was so successful that the hum became inaudible at the nearest house. A 19 dB attenuation in the hum sound was achieved. This was considerably higher than could have been provided by fitting a silencer / attenuator into the ductwork. Our noise cancellation solution was entirely made from steel, so could withstand all kinds of weather including any rain water that entered the fan via the exhaust stack. There was no loss in extraction performance.
The above examples show that our fan noise control solutions can provide exceptionally large sound reductions and considerable cost savings. Another benefit of our specialist fan noise solutions is that they do not restrict airflow, so there is no loss of suction or extraction performance. This contrasts with some types of silencer, which can reduce fan and extraction performance due to their high airflow resistance.
Where the air is very dusty or dirty a silencer can become clogged, which can considerably impair the sound reduction achieved. Our advanced / engineering fan noise reduction solutions do not clog and are completely unaffected by dust or dirt in the airflow.
Silencers can be unacceptable in the food, drinks and pharmaceutical industries for hygienic reasons, due to the risk of contamination from the silencer absorption material. Our advanced noise control solutions are fully hygienic and contain no material that could contaminate food, drink or pharmaceutical products.
Where our advanced fan noise control techniques cannot be applied and a very high sound reduction is needed, we often purpose-design a high performance silencer that combines very high attenuation with negligible resistance to airflow.
Our specialist fan noise suppression company offers high performance sound attenuation solutions to manufacturing, industrial and commercial companies throughout the UK. Companies can benefit from much higher noise reductions and save thousands of pounds by choosing our advanced fan noise cancelling techniques instead of more expensive, less effective options like acoustic enclosures, screens and barriers. To find out how to reduce extractor fan noise with our help, please click on contact us to reduce fan noise.
Advanced Noise Solutions Ltd : 01727 864667
helping to reduce fan noise for industry