Self-Financing Noise Control - Innovation and New Technology
Best Practice in noise control  - without acoustic enclosure, silencers, lagging...
We have a reputation for developing low cost innovative engineering noise control techniques that are often an order of magnitude less expensive than conventional palliatives such as acoustic enclosures and silencers. Many of these INVC solutions are accepted as defining what constitutes noise control "best practice" based on current technology - particularly where maintenance, access, hygiene and productivity are important. This graphic shows examples of Self-Financing Noise Control (click for technical note) projects across a wide range of plant categories. These illustrate not only the cost savings that are often inherent in engineering noise control measures compared with enclosures, silencers etc, but also the estimated pay-back period after which the modifications will generate a profit. In many cases, the noise control modifications can be justified simply on the grounds of increased performance and productivity, with the noise reduction as an additional benefit. Summarising some of the features of these examples:-
- vibratory feeders: elimination of fatigue, increased product feed rate by 100%
- fans: eliminated silencer losses and down-time for cleaning
- 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
Noise Control Innovations - Case Studies - no acoustic enclosures, silencers, barriers...
Page down or click to view some of the unique noise control techniques developed to control noise and vibration at source.
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Noise Control Audit
The new noise regulations 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 now quantify their noise control options rather than simply repeating 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.
| Instead of paying for unnecessary repeat risk assessments under the new regulations, 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 the INVC 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.
More Sound Solutions - Noise Control Database
More Sound Solutions is a large collection of low cost engineering noise control case studies that do not involve enclosures (continuing the above theme). This is the ideal starting point for anyone with a noise problem as it provides a showcase for
current “best practice” in noise control - as illustrated by the examples below.
Best Practicable Means (BPM) / Best Available Technology (BAT) - Environmental Noise Control
Environmental noise is an increasingly common - and potentially expensive -problem. We have developed a simple procedure that enables you to determine just what constitutes BPM / BAT for any environmental noise control problem. Combined with new noise control technology, enormous cost savings can be made to meet noise targets by wielding an engineering scalpel to excise the noise at source as illustrated by some of the case studies below - or go to our environmental noise web page.
SAMPLE NOISE CONTROL CASE STUDIES
Quiet Fan Technology - QFt: Fan Noise Control
Fans are by far the most common source of environmental noise complaints. QFt is a unique noise control technology developed by the INVC that sidesteps conventional noise control techniques completely. Retro-fitted inside the centrifugal fan casings, it permanently eliminates tonal noise at source for the life of the fan at a fraction of the cost of conventionalsilencers, enclosures and lagging - and without reducing efficency.
Click icon for sound.
Scrap Fan Noise Control
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, enclosures and 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 a cost of c £100/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 with no visible sign that it is quiet...
.. and this noise signature illustrates the reduction in tonal noise achieved
Quoting the client "!?@!*%$ amazing!". We could not have put it better ourselves!.
Dynamic Vibration Absorbers
We 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 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 (which spoils 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
The noise from this 115T Bliss power press was reduced by 90% 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 absorbers 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 vibration absorbers fitted to the main gear wheels on a wire draw bench reduced theoverall noise by 5dBA - again with no effect on normal operation, access or maintenance and at a cost saving of c £13000.
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.
Dual Fuel Burner Noise Control
The cause of complaints about environmental noise levels was traced to this dual fuel burner on a Heinz site. The company contacted us to assess the noise control options. The source of the problem was diagnosed as a 116Hz low frequency "drone" - a very common type of burner noise. The conventional palliative noise control techniques for this sort of problem involve fitting large silencers into the stack and converting the boiler house into an acoustic enclosure - eye-wateringly expensive with extensive down-time (which would have caused serious production problems).
Our alternative solution was a set of aerodynamic modifications fitted inside the combustion head. These reduced the drone by 16dB, completely eliminating the problem. The cost? Less than £2k with a down-time of a few hours. This new technology is an incredibly cost effective solution to many burner or combustion noise problems.
Impact Noise Control
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
Scrap Impact Noise Control
.. £250 000 cost saving on environmental noise control...
We saved a scrap recycling company over £250 000 on noise barriers by controlling the scrap impact noise at source. This is new technology that can reduce impact noise from crushers in quarries, dump trucks, shredders, trains, manual handling etc by up to 15dB(A). Compared with conventional noise control techniques, the cost is miniscule, it is incredibly rugged and has no effect on plant operation, maintenance or access.
Other Noise Control Examples
We have a host of other engineering noise control applications, ranging from a 15dB reduction in sugar beet hopper impact noise, numerous vibratory feed hoppers and conveyors in the food and pharmaceutical industries, 10 - 12dB(A) noise reductions on Ishida weighing machines...
Press Shop - Environmental Noise Control Problems
Complaints about press noise from a factory unit had resulted in an Abatement Notice. After the company had spent £12000 on the building to no avail (and with another £65000 expenditure planned), the INVC Best Practicable Means (BPM) Noise Control Audit for the Local Authority proved that the best solution was to treat the presses at source. This not only reduced the low frequency components by 9-24dB, but also reduced the cost by c 85%.
Noise Control on Induced Draught Fans
CMB asked the INVC to determine what constituted the Best Available Technology (BAT) in noise control to minimise the noise 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 silencers, enclosures and an earth berm.
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 - and at a fraction of the cost and hassles associated with the conventional noise control package.
Cool Chiller Noise Control
The conventional techniques used to reduce chiller noise involve erecting barriers and fitting silencers. These are not only high cost noise control measures, but they can also reduce the efficiency of the chillers themselves.
The INVC developed alternative is a set of low cost engineering noise control modifications that not only reduced the overall noise from this chiller at source by 8dB(A), but also eliminated the tonal content (worth an additional 5dB(A) noise reduction with respect to environmental noise limits) - and with no effect at all on chiller performance or access.
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Direct Links
noise control audit - digital noise assessment - noise competency training - noise training - product noise control - fan noise control - VWF (Vibration White Finger) - Hand-Arm Vibration (HAV) assessment - HAV competency training - HAV database (HAV-Base) - Whole Body Vibration (WBV) measurement - environmental noise control - noise nuisance - environmental noise monitoring - production line testing (noise and vibration) - noise nuisance / annoyance recorders - frequency analyser and noise analyser software
Industrial Noise & Vibration Centre
889 Plymouth Road, Slough Berks SL1 4LP
Tel: 01753 698800 Fax: 01753 567 988
email:consult@invc.co.uk |
