Industrial Noise & Vibration Centre

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Remote Control of Noise by Email

Access best practice noise control from anywhere - despite Covid...

For many noise problems, particularly environmental, we can get the diagnostic information needed to identify sources via smartphone without a site visit. This free service gives you access to a worldwide database of noise control solutions that reduce typical project costs by c 80%. We then email you the best practice costed options. Subsequently, we can design a detailed solution for implementation by local contractors.

Fast and efficient "Remote Control", eliminates the need for most site visits - extremely useful during the Covid lock-down...

Previous service users saved $1 million from a $1.25 million contract and £28k from a £31k quote. Why not check your options?

Remote Quote

Noise problems? Get a free 2nd opinion by email to see if there's a better, more efficient and lower cost option available.

Remote Diagnosis

Email us smartphone data for a precise and free diagnosis of your noise problems and your costed options.

Remote Noise Control

We can provide optimum, low cost solutions to a growing proportion of noise control problems by email.

Remote diagnosis – export your noise problem

Many noise problems drag on for months or years due to poor diagnosis and the imagined high cost of mitigation – despite the existence of simple, low cost alternative noise control solutions. These delays come at a high cost to sites (hearing damage risk, PPE, audiometry, assessments etc) and, for environmental noise, the costs to regulators, the perpetrator (time, bureaucracy, legal fees etc) and to complainants who continue to suffer needless stress that affects their health.

Contact us – one call and one email may be all that is necessary to check if there is a better solution and to resolve many long-standing noise problems within weeks, or even, in some cases, within a few days…

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Remote control of noise by email - the process..

  1. Email us information: email us a description, photos, a smartphone audio or video clip (c 10 secs) for each item of noisy plant + noise data/report (if available)
  2. Analysis and diagnosis: we review and analyse the recordings, make an accurate diagnosis and assess the noise control options against our database, requesting any additional information we may need
  3. Noise control options: we email the results and an assessment of the optimum noise control option(s) with estimates of costs and noise reductions for you to use as evidence of current best practice. To this point, this can be a free service
  4. Detailed recommendations: we can then often provide detailed noise control recommendations by email. This includes drawings, material specifications and potential suppliers in sufficient detail such that any competent local contractor can implement. As the solution is often so much cheaper, simpler and easier to implement than previously expected (see case studies for examples), it is very likely to get done quickly...

Remote control of fan noise - quick and simple

We have carried out numerous and varied fan and stack noise attenuation and chiller noise reduction projects across the globe by email from our offices. Use the following procedure to get an evaluation of the costed options – or a 2nd opinion about potential alternatives to a noise reduction quote – quickly by email and free of charge.

For example, where our innovative fan noise control technology is appropriate, 80% cost savings, a 90% reduction in downtime and 20% improved efficiency are possible compared with conventional silencing. Simply email us the following:-

  1. Photos: photos of the fan installation – both of the fan itself (from both sides) and of the surrounding structure (ductwork, stack etc). For axial fans, close-up photos of the fan and motor installation
  2. Location audio recording: for environmental noise problems, a smartphone audio recording or short video clip (c 20 secs) taken at a location where you can clearly hear the fan tonal noise, but at some distance from the fan(s). The best location is usually out towards the problem area (if you can hear the fan during the day with few other noise sources to interfere) or at the site boundary. In either case, we need a recording that illustrates the problem noise – i.e. play it back to check you can hear the drone / tone / hum etc
  3. Close-up audio recording: in addition to 2 above or for occupational noise problems, a short audio or video recording close to the fan (c 2m – 5m) for the local noise environment
  4. Fan information: fan speed and number of blades on the impeller for each fan
  5. Multiple fans: repeat the above for each fan if there are multiple fans – although we may only need one off-site recording
  6. Analysis, diagnosis and noise control options: we review and analyse the recordings, match the noise signatures with the fan characteristics and request any additional information that we may need. Provide you with the costed noise control options based on current best practice. To this point, it is a free service
  7. Detailed silencing recommendations: we can then often provide detailed noise control recommendations by email, including drawings, material specifications and potential suppliers in sufficient detail such that any competent local contractor can implement. This is both convenient and keeps costs to a minimum
ID fan noise reduction

A BP refinery in the USA had been quoted $1.25 million for silencers for five 1.5MW double entry ID fans that had been the cause of extensive noise complaints. Their acoustic consultant had come across our aerodynamic fan noise control technology on the web and contacted us for advice. He sent his noise data to us by email and we identified that our technology would work well on the fans.

ID fan fitted with noise attenuation technology

We used the information provided to design the aerodynamic modifications and sent drawings so that the components could be made locally. After installation that required a tiny fraction of the down-time associated with fitting attenuators, the 180Hz blade pass tone had been completely eliminated (>12dB reduction), preventing any further noise complaints.

The total project cost for all the modifications not only saved over $1,000,000 compared with the quotations for conventional silencers, but, in contrast with traditional mufflers, the modifications had no effect on fan efficiency and will last the lifetime of the fan with zero maintenance. No site visits were required, saving time and resources (transatlantic flights etc).

Axial extract fan silencing at source

4 large axial extract fans caused noise complaints over a wide area in Canada, despite multiple attempts at noise control based on conventional techniques. One email led to the noise being reduced by 99% with no site visits required - the whole project was completed over the internet.

Mitchell, the site engineer sent us an email with smartphone video clips and photos. Sound track analysis showed the problem to be high level tones at the 197Hz blade pass and harmonics. We used the photos to design retro-fit aerodynamic noise reducing components which the client made and installed to give 20dB attenuation at 100m.

"We are exceptionally happy with the overall results that were obtained, from a noise reduction, cost, and time stand point. INVC was very professional and prompt on all deliverables. Out of all solutions attempted this was by far the best and cost effective. The whole process was very smooth from first contact to installation … glad we went with INVC, thanks…"

In addition to the noise reduction, the performance of the fans was also improved which means that the project will pay for itself in reduced running costs.

Chiller fan noise reduction

Attempts are often made to solve classic low-frequency chiller fan noise using conventional silencers and noise barriers. Despite the fact that there is zero chance that these techniques can work at low frequencies, a fortune is still wasted every year on these useless palliatives. Previous failed attempts on this air cooled chiller (48.5Hz and harmonics) were replaced with aerodynamic techniques that reduced the tones by 95% and improved the fan efficiency – all by email via forwarded video clips and photos.

The company had already tried using a barrier to mitigate the noise complaints to no avail. This is because barriers are almost completely ineffective at frequencies below around 200Hz (drones, hums etc). Chiller and AHU fans regularly generate low-frequency tones as the blade pass hum often falls in this range. Whilst acoustic barriers and attenuators can be used to reduce the overall dB(A) noise level, they do not touch the low-frequency tones that are very commonly the actual cause of complaints. Our analysis of emailed video clips ca immediately confirm whether this is the case, avoiding potentially costly mistakes. In contrast, our aerodynamic axial fan noise reduction technology addresses the low-frequency noise problem by reducing it at source with increased fan efficiency as a common additional benefit.

Click this link for more detailed information on the best approach to noise attenuation for chiller, air condenser, HVAC and refrigeration fans.

Cooling tower noise reduction - gearbox

Cooling tower noise had triggered complaints as the noise was highly tonal. This led to a £31k quote from the supplier to replace the whole fan unit on the recommendation of their noise consultant. The local EHO suggested they contact us for a 2nd opinion.

We asked for a video clip by email, analysis of which allowed us to determine that the problem tone was at the tooth meshing frequency of the pinion gear. As a result, the gearbox was replaced at a cost of £3k. The whole process from 1st phone call to the provision of a detailed proposed solution took less than 1 day…

This cooling tower noise reduction project is yet another example of the very poor diagnostic and engineering knowledge of many noise consultants. Far too often, decisions about noise control measures are made based on assumptions about noise sources rather than on accurate and precise diagnosis. There is a simple diagnostic process that must be followed when evaluating cooling tower noise control projects. This case study illustrates the power of simple, accurate diagnosis to remove all guesswork in solving noise problems quickly and at very low cost.

Detailed guide to selecting cooling tower noise attenuation techniques >

Schiller biofuel power station fan noise attenuation.jpg

The efficiency of a 3m, 1.5MW wood burning boiler fan installed at Schiller power station in New Hampshire (one of the largest renewable energy projects in the U.S.) was dramatically improved by replacing a power station wood burner fan noise reduction at source traditional silencer with our aerodynamic noise control technology.

Schiller ID fan remote control of noise.jpg

The fan feeds a stack that included a large conventional silencer to prevent noise complaints from local residents. As the silencer had a drastic impact on fan efficiency, it was removed and our aerodynamic source control technology retro-fitted within a 12-hour downtime window. This not only eliminated the low-frequency tonal noise problem at a minute fraction of the cost of the silencer it had usurped, but as it also reduced the fan power consumption, it soon paid for itself.

This international project was managed remotely from our UK offices. By analysing and interpreting data acquired locally to our specifications, we were able to dispense with site visits and reduce the entire process from initial contact to problem solved to a matter of weeks.

Failure of acoustic lagging in fan noise control

As a result of complaints about noise from 2 large centrifugal fans on a factory roof and the involvement of the Environment Agency, the company had spent £50k on acoustic lagging that had zero effect on noise levels. The result was a prolonged wrangle with the authorities – who eventually suggested that they could try to get a 2nd opinion from us (this is a free analysis and diagnostic service).

They forwarded a video-clip. Analysis of the sound-track proved that the problem was a pair of tones at the blade-pass frequencies of the 2 fans plus 1st harmonics that were interfering and “beating” with each other. We designed the solution (Quiet Fan technology – retro-fit attenuation without silencers) that eliminated the tones as a feature within a few weeks and at a fraction of the cost of conventional alternatives. Only a single site visit was required – the rest of the work was carried out by email.

Garage chiller noise reduction

Highly tonal noise from these chillers had been the cause of complaint for some considerable time. The company had already attempted acoustic enclosure with the result that the chillers had over-heated.

The EHO sent us sound recordings, photographs and noise levels. Once analysed, we were able to say that the noise problem could be resolved for a few hundred pounds without running the risk of chiller problems. Once this information was passed on to the garage, they contacted us and we supplied them with detailed drawings that they used to get the silencers made locally.

Problem solved…

Analysis of the smartphone video sound-track shot outside the complainant’s house and close to potential noise sources on an industrial site allowed us to pin-down the source of the low frequency tone that had been the cause of long term complaints. Based on the mechanical information provided, we proved that the culprit was not the fan previously diagnosed locally, but a vibratory sieve. We then provided a virtually cost-free modification (mechanical disconnection from the building steelwork) to solve the problem. The whole process cost a few hundred pounds and only took a few days.

A pair of air compressors installed in a plant room were generating noise levels well above the specified 80dB(A). We discussed the installation with the contractor, who then took some basic noise measurements plus photographs and smartphone recordings which were forwarded by email. As we have extensive experience of these types of compressor, we could use our noise control database as the basis for developing the solutions.

We designed retro-fit silencers and wall treatment, returned the recommendations and solved the problem by reducing the noise to well within the purchasing specification within a few days. The whole project cost less than a single site visit…

Power pack damped  acoustic enclosure

The manufacturer of hydraulic power packs for offshore use had to meet a tight customer Buy Quiet noise purchasing specification. As the pack had to be fitted with a steel frame for other reasons, we designed:-

  • source control measures for the hydraulic power pack (high damping on key panels)
  • technical features of the acoustic enclosure panels
  • bespoke cooling air silencers within the very limited space

The details were developed in conjunction with SoundDampedSteel who supplied both the highly damped laminated steel used and the enclosure itself to our specification. Our involvement was carried out entirely by email and mobile phone using streamed pictures from site.

Your problem may already be solved

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