Industrial Noise
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Occupational noise control

Profit from Noise Control Best Practice

Our many clients benefit from award winning, innovative new technology in occupational and high hygiene noise control. Simpler, faster and providing 50% – 80% cost savings over conventional techniques such as acoustic enclosures, silencers, lagging…

New technology dramatically reduces the costs of noise control from machinery and plant compared with acoustic enclosures, silencers, lagging etcA reputation as the major UK developer of innovative engineering noise control techniques is a reassuring guarantee that we can solve your noise control problems in the most practical and cost effective manner possible. Many of our solutions define current noise reduction “best practice” – particularly where maintenance, access, hygiene and productivity are important. There are also many examples where our recommendations have increased profitability through higher productivity and reduced down-time. Our noise control technology is also ideal for the conventionally “difficult” food / drink, electronic and pharmaceutical industries.

Self-Financing Noise Control – profiting from new technology

We have many examples of Self-Financing Noise Control projects across a wide range of plant categories and industries illustrating the cost savings inherent in engineering noise control measures compared with conventional palliatives such as acoustic enclosures, silencers, lagging etc. In many cases, the noise control modifications can be justified simply on the grounds of increased performance, efficiency and productivity, with the noise reduction as an additional benefit. A few examples are listed below.

      • vibratory feeders: elimination of fatigue, increased product feed rate by 100%
      • fans: eliminated silencer losses and down-time
      • weighing machines: elimination of acoustic enclosures, improved access for maintenance and cleaning
      • burners: conventional noise control measures insufficiently effective to avoid requirement to shut-down plant
      • power presses: enclosures eliminated – reduced down-time
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Occupational Noise Control Audit – eliminate placebo assessments

The occupational Control of Noise at Work Regulations (CoNaWR) require a seismic shift in attitude to noise management in the workplace. Quoting the guidance – “these regulations are concerned with controlling noise, not measuring it…”. Consequently, companies must quantify their noise control options rather than simply repeating placebo risk assessments that usually include little or no information on the topic. Moreover, PPE can no longer be used for long term risk management unless it can be proved that noise control is impractical. We can also provide the audit as part of benchmark noise assessment.

Instead of paying for repeat placebo risk assessments, implement a noise control programme that actually reduces the risks – and potentially pays for itself …

The most effective way to meet these regulatory requirements is our Occupational Noise Control Audit – either in place of a repeat risk assessment (saving the associated costs) or appended to a conventional risk assessment update. It is an engineering audit that generates a costed list of the noise control options and associated benefits either for a single machine or for a whole site using the best of current technology. The results not only provide the basis for planning the most practical and cost effective noise control programme possible, they also provide certification for plant where it is shown that noise control is not practical.

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More Sound Solutions – noise control case study database

More Sound Solutions is probably the largest collection of low cost engineering noise control case studies available that do not involve enclosures. This is the ideal starting point for anyone with a noise problem as we may well have already solved it using current “best practice” in noise control. Take a look through the examples below…

Quiet Fan Technology (QFt) – fan noise control without silencers

quiet fan technology is best practice to reduce fan tonal noise without noise attenuators or acoustic enclosuresThis is a unique noise control technology we have developed that sidesteps conventional noise control techniques completely. It permanently eliminates tonal noise at source for the life of the fan at a fraction of the cost of conventional silencers, enclosures and lagging – and without reducing fan efficiency (unlike conventional attenuators). Applications include: extract fans, ID fans, chillers, air conditioning, process and ventilation fans… Read more on industrial fan noise reduction.

Scrap Fan – occupational and environmental noise control 
fan noise reduction withoiut silencers or attenuators or lagging or acoustic enclosures...High levels of tonal noise from scrap can fans were causing both occupational and environmental noise problems. Instead of fitting conventional noise control measures in the form of silencers, acoustic enclosures and noise lagging at a potential cost of £30k or more per system, our bespoke Quiet Fan technology (QFt) was fitted inside the fan casings in a matter of hours to give an overall noise reduction of 22dB(A) at an installation cost of c £200/fan.

Unlike silencers, the noise control modifications had no effect on fan efficiency, are unaffected by the passage of scrap cans and will last the lifetime of the fans without maintenance. This picture is of a modified fan showing no visible sign that it now generates less than 1% of the previous noise level…

canfan be3fore after

Quoting the client “!?@!*%$ amazing!”. We could not have put it better ourselves!

Noise Control on Induced Draught Fans
forced draft thermal oxidiser fan noise reduced at source without noise enclosure, acoustics barriers or noise laggingCMB asked us to determine what constituted the Best Available Technology (BAT) in noise control to minimise the sound from a new regenerative thermal oxidiser plant. The result was a set of precisely targeted modifications to reduce each of the components contributing to the subjective impact instead of conventional noise control measures consisting of large attenuators, acoustic enclosures and an earth berm noise barrier.

draft fan

QFt removed the tones; one fan was slowed by 100rpm to remove “beating”; damper type and position changed to improve flow; modest conventional attenuators added to reduce broadband noise. These modifications removed all noise “features” and reduced the overall noise by 15dB(A) making the plant virtually inaudible – at a tiny fraction of the cost and hassles associated with the conventional noise control package.

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Hygienic / Clean / GMP Noise Control

Pharmaceutical, drinks, electronics, food and confectionery…
high hygiene noise reduction technology for clean industries“Clean” industries where hygiene and cleanliness are paramount (food and drink, pharmaceutical, electronics…) have been caught in something of a cleft stick with respect to noise control as conventional solutions can cause hygiene and maintenance problems. However, new, high-tech materials coupled with our innovative engineering source control techniques are revolutionising the reduction of noise in these clean industries.

The Perfect Combination…

Coupling new acoustic materials and systems with engineering source control technology is re-defining what constitutes noise control best practice in the food, drink and pharmaceutical industries. Conventional acoustic materials (foam, fibreglass, rockwool) pose an unacceptable hygiene problem. However, the new generation of sound absorbent systems developed by Ecophon are suitable for use in GMP (Good Manufacturing Practice) and high care areas, and will withstand aggressive cleaning regimes, including pressure washing.

Installing these new materials can provide substantial reductions in area noise levels and can even simplify cleaning processes. However, noise hot-spots will often remain near noisy plant or processes. These are tackled using engineering techniques that reduce noise at source using materials such as laminated stainless steel from SounddeadSteel. We have invested heavily in the development of new techniques specifically for hygienic applications in clean industries that can be implemented quickly and painlessly – often as an extension to a maintenance schedule. These noise control techniques are ideal for the pharmaceutical, electronic and food and confectionery industries where hygiene is a key requirement.

Weighing Machine Noise Control 
weighing machine hygienic noise control at source in the food, pharamceutical and confectionery industriesWeighing machines often generate noise levels of 90 – 100dB(A). The conventional approach is to fit partial or full enclosures round each machine. These often produce a noise reduction of only c5dB(A) (and even an increase at the operator in some cases…) at a cost of the order of £6000 – £15000 per machine – and with the associated access and cleaning problems. We have developed source control techniques that reduce noise levels by 10 – 12dB(A) (typically) with no effect on normal operation, cleaning, hygiene or access – and at a small fraction of the cost of enclosure. Successful applications range from confectionery to pharmaceuticals to meat product processing.weighing-noise-control

Die-Header / Tablet Machine Noise Reduction
food industry die header tablet machine clean noise controlThe noise from die header machines used to manufacture hard sweets, tablets and other products in the food and pharmaceutical industries is often 95 – 101dB(A). The conventional approach is to fit them with high cost acoustic enclosures that cause serious access problems and also makes cleaning difficult. Even where enclosures are fitted, noise levels are often still close to 100dB(A) or more. In this case, our solution was based on a precise diagnosis of the source of the noise. This allowed us to more than halve the noise by developing a re-designed cam – which also extended the life of the cam significantly and reduced operating costs. Coupled with hygienic close shields, this has reduced noise levels by 10dB or more at low cost.

Reducing Noise from Air Transport Fans
pharmaceutical clean air transport fan noise reductionNoise levels in a pharmaceutical manufacturing area were 95-100dB(A). A hygienic absorption system could be used to reduce the average noise level by 5-10dB(A), but would leave hot-spots of up to 95dB(A) near the air transport fans. As strict hygiene requirements ruled out conventional silencers, novel inserts were fitted inside the fan casings to reduce the tonal noise from these units by close to 20dB with no hygiene or performance implications over the life of the fans. With the local fan noise eliminated, the combined performance would be to reduce operator exposures to below 85dB(A), allowing PPE to be made advisory.

Noise Control for Vibratory Hoppers, Feeders, Conveyors, Separators …
The noise from dozens of vibratory feed hoppers in a pharmaceutical plant generating 95 – 99dB(A) was reduced by 22dB by designing retro-fit modifications to the geometry and introducing sophisticated damping. There were also other benefits as the modifications substantially improved product feed and eliminated persistent fatigue cracking. The cost was not only a tiny fraction of the c £100000 required to fit conventional enclosures, but there was no effect on normal operation or access and productivity was actually significantly improved. A similar approach has also been successfully applied to noise control on vibratory bottle feeders to give an 8dB(A) reduction at a cost of c£500 and with substantially improved performance and productivity.

Clean Noise Control in Vibratory Feeder / Vibratory Grader Areas
drinks and pharmaceutical industry hygienic vibrator feeder hopper noise reductionTypical local noise levels from these types of plant in the food industry are often in the range 90 – 100dB(A). In many cases, it is possible to avoid the use of costly acoustic enclosures (with their attendant access and cleaning problems) via a combination of the new “clean” acoustic absorbent (wall or ceiling systems) coupled with engineering modifications to the plant. Projects include:- multiple vibratory feed hoppers – area de-regulated without spending the £100,000 quoted for enclosures, with improved productivity and the elimination of fatigue cracking; vibratory feeders – area de-regulated and throughput doubled by improving vibrator efficiency; vibratory graders – area de-regulation via source control and replacement of existing enclosure lining.

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General Noise Control Examples

Power Station 600hp Pumps Noise reduction
power station water pump noise reductionThese water pumps generated 95 – 99 dB(A) and were the subject of a dispute with the supplier re the agreed noise levels. Various acoustic barriers and partial enclosures were being considered – at high cost and considerable issues with access. Our diagnosis based on detailed vibration analysis proved that the required noise reduction could be achieved simply via constrained layer damping plus laminated close shields. When installed, these provided a 12dB(A) noise reduction with no effect on access, operation or maintenance – and at a tiny fraction of the cost. More information is available on the Sound Damped Steel installer website here.

Hydraulic Billet Guillotine
96 dB(A)Leq was recorded during operation of a 250 ton Rhodes billet hydraulic guillotine. Instead of a high cost acoustic enclosure, we determined that the noise was dominated by high levels of transmitted vibration from the motor-pump unit to the machine frame (and through rigid pipework to the remainder of the machine) and the transmission of impacts from the valve-bank. The motor-pump unit was mounted on a rigid frame that was then isolated from the machine body and the valve bank isolated using rubber-cork composite. This reduced the noise level from 96 dB(A) down to 79 dB(A).

Power Station Gas Facility – high damping noise reduction
power station gas reception facility noise control via high damping acoustic laggingNoise from a power station was uncomfortably close to their environmental noise planning conditions. Detailed diagnosis proved that the dominant contribution was high frequency noise (>500Hz) radiated by the Gas Reception Facility. Vibration measurements narrowed-down the source to the reducer, expander and associated valve section of the facility. Sound Damped Steel was brought in to fabricate our innovative, high performance acoustic lagging. This has an outer skin constructed from highly damped laminated steel, making it very tolerant of installation practicalities. Moreover, options are available that eliminate the corrosion problems inherent in conventional lagging designs. The diagnostic process illustrates how costs can be kept to an absolute minimum by precisely ranking noise contributions from different components, even amidst complex arrays of pipework , valves and other sources. The effect of the treatment was to reduce the noise from this source by 16 -19dB(A), eliminating it as a contributor off-site. Occupational noise levels in the area were also reduced by an average of 8dB(A). More information is available on the Sound Damped Steel installer website here.

Supermarket Food Tray Washing Line Noise Control
supermarket tray wash noise reductionTwo newly installed automated lines had failed to meet the Christian Salvesen noise specification despite the efforts of the supplier. Our engineering audit predicted both the cost and the precise noise levels that could be achieved using best practice control techniques. Following implementation by the manufacturer, noise levels were reduced from typical levels of 85 – 91dB(A) down to the 82dB(A) target and with more efficient drying performance. The manufacturer has adopted the more effective, lower cost and more practical INVC technology as standard practice, improving performance and margins.

Alternator End Casting Machining Noise
casting machining noise reduction using dampersMachining of alternator end castings produced 104 dB(A) at the operator, dominated by a “squeal” radiating from the casting. Overlapping hanging strips had been fitted round each machine in an attempt to reduce noise – but in every case they had been cut down at the operator location to improve access. Frequency analysis showed the dominant tones were excited by cutting forces with evidence of chatter-marks on some of the machined surfaces. We designed a low cost damper to reduce the casting vibration. This reduced “squeal” tone by 32 dB and the overall noise level by 16 dB(A) at source which also improved the quality of cut was improved and reduced the machining cycle time.

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Dynamic Vibration Absorbers for Noise and Vibration Control

dynamic vibration damping to control noise at sourceWe have developed and applied the same technology used to solve the Millennium Bridge sway to control noise and vibration for industrial applications with great success. The solution involves attaching small dynamic vibration absorbers (or dynamic vibration dampers) to the structure that cancel the vibration at the point of attachment. On the famous bridge, these add a virtual stiffness equivalent to large concrete piers (spoiling the ride…). Our industrial noise control uses include 10 – 20dB of noise and vibration control on power presses, grinders, gearboxes, dynamometers and pipe-work.

Power Press and Draw Bench Noise Control – via vibration dampers 
power press noise control using dynamic vibration dampersThe noise from this 115T Bliss power press was reduced by 90% (10dB) by analysing the flywheel vibration and then bolting £15 worth of small steel blocks mounted on gasket springs at specific points. These tuned dynamic vibration dampers cancel out the flywheel vibration, fit inside the existing guards and were installed in a few hours.

Compare this with the cost and access problems associated with the only alternative noise control measure – a high cost conventional acoustic enclosure.

Similar dynamic vibration dampers fitted to the main gear wheels on a wire draw bench reduced the overall noise by 5dBA – again with no effect on normal operation, access or maintenance and at a cost saving of c £13000.

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Burner and Combustion Noise Control at Source

Conventional noise control techniques such as stack silencers and converting buildings into acoustic enclosures involve costs that would make a hardened accountant weep! Our new technology can often reduce the noise from these sources at a fraction of the cost of traditional noise control measures and with virtually no disruption or down-time.

Yoghurt – Based Dual Fuel Burner Noise Control
combustion noise control at source on this industrial burnerThe cause of complaints about environmental noise levels was traced to this dual fuel burner on a Heinz site. The company contacted us for a second opinion of the noise control options as the  conventional techniques involve fitting large silencers into the stack and converting the boiler house into an acoustic enclosure – eye-wateringly expensive with extensive down-time. The source was diagnosed as a 116Hz low frequency “drone” – a very common type of burner noise control problem – and with a stunning simple solution.

yoghurt based combustion burner noise controlOur alternative solution was a set of aerodynamic modifications using an adapted yoghurt pot fitted inside the combustion head (initial trials) – the only known yoghurt-based noise control application…. This reduced the drone by 16dB, completely eliminating the problem. The cost? Less than £2k with a down-time of a few hours. This new approach and technology is an incredibly cost effective solution to many burner or combustion noise problems.

Drying Oven Burner Noise Reduction at Source
burner combustion noise reduction at source12 burners on a drying oven generated 95dB(A) with an 82Hz “boom” as the dominant component. This was not only a very annoying occupational noise hazard, but also a potential environmental noise issue. An acoustic enclosure was being considered, but was deemed too costly and impractical. Building modifications were also under consideration until they contacted us to see if there was an alternative. We diagnosed an organ pipe resonance caused by combustion mixture problems which we solved by sourcing and modifying off-the-shelf weld extract motor controlled valves. A 21dB noise reduction at source for less than the cost of an acoustic door…

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Impact Noise Control – chutes, bins, conveyors, hoppers….

We have developed a suite of new impact noise control techniques that typically provide 10-20dB reductions and are more effective than conventional technology.

      • Applications: chutes, hoppers, conveyors, bins, recycling plant, scrap yards, train/truck loading/unloading, quarries …
      • Benefits: rugged (often harder wearing than the untreated surface); low cost; hygienic

Additional Noise Control Examples
We have a host of other engineering noise control applications across a wide range of industries – contact us to discuss particular plant or machinery in detail.

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