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Brick oven fan noise control

The Problem

Brick oven fan noise control

A large 3.5m diameter brick oven fan was the cause of both occupational and environmental noise problems (the latter involving the local Environmental Health Officer). Occupational noise levels in the room next to the fan were dominated by low frequency tones giving an overall level of 90dB making the use of hearing protection mandatory. Tonal noise was also the cause of the environmental noise problem. Quotations for conventional treatments involved an enclosure, a requirement to move the fan to create space for a large silencer and a down-time of a few days. The overall cost would have been over £15000 and would have caused serious production difficulties as the fan is run 24 hours a day.

The Solution

  • Analysis of the noise showed that the low frequency tone was at the blade passing frequency of 62.5 Hz (468 rpm fan speed and 8 blades with a level of 112dB.
  • The tone was radiated by the fan casing and ductwork and also propagated up the chimney into the local environment.
  • Source control techniques developed by the INVC were used to design retro-fit modifications for the fan that fitted inside the fan casing.
  • These were fitted during scheduled down-time of a few hours and reduced the blade passing tone from 112dB down to 99dB and the noise level in the 63Hz octave band by 22dB (99% reduction) as shown below.

The Results

The overall noise level was reduced from 90dB down to 79dB.

Brick oven fan noise control noise reduction graph

Brick oven fan noise control noise reduction graph

The Costs

This eliminated both noise problems quickly and effectively and at the same time reduced the overall cost from £15000 down to £1000. Moreover, no additional down-time was required to implement the modifications.

Noise Control Method

Fan modifications.

Client

Butterley Brick

Consultant

Industrial Noise and Vibration Centre Ltd.

Link URLs in this page

  1. Noise at workhttps://www.hse.gov.uk/noise/index.htm
  2. Regulationshttps://www.hse.gov.uk/noise/regulations.htm
  3. Worried about your hearing?https://www.hse.gov.uk/noise/worried.htm
  4. Overview - Worried about your hearing?https://www.hse.gov.uk/noise/worried.htm
  5. Audio demonstrationhttps://www.hse.gov.uk/noise/assets/video/index.htm
  6. Overview - Advice for employershttps://www.hse.gov.uk/noise/advice.htm
  7. Employers' responsibilitieshttps://www.hse.gov.uk/noise/employers.htm
  8. How do I assess the risks?https://www.hse.gov.uk/noise/risks.htm
  9. Managing noise risks checklisthttps://www.hse.gov.uk/noise/checklist.htm
  10. Overview - How do I protect my workers?https://www.hse.gov.uk/noise/protect.htm
  11. How do I control the risks from noise?https://www.hse.gov.uk/noise/controlrisks.htm
  12. Use the information from my risk assessment?https://www.hse.gov.uk/noise/useinfo.htm
  13. Reduce noise?https://www.hse.gov.uk/noise/reducenoise.htm
  14. Choose quieter equipment and machinery?https://www.hse.gov.uk/noise/choosequieter.htm
  15. Hearing protectionhttps://www.hse.gov.uk/noise/hearingprotection.htm
  16. What do I need to tell my employees?https://www.hse.gov.uk/noise/assets/video/tell-index.htm
  17. Employee and safety representativeshttps://www.hse.gov.uk/noise/safetyrep.htm
  18. Health surveillancehttps://www.hse.gov.uk/noise/healthsurveillance.htm
  19. Advice for manufacturershttps://www.hse.gov.uk/noise/advice-for-manufacturers.htm
  20. Noise calculatorshttps://www.hse.gov.uk/noise/calculator.htm
  21. Key messageshttps://www.hse.gov.uk/noise/keyfacts.htm
  22. Overview - Industry good practicehttps://www.hse.gov.uk/noise/goodpractice/index.htm
  23. Overview - Managing noise riskshttps://www.hse.gov.uk/noise/goodpractice/managingrisks.htm
  24. Over-protectionhttps://www.hse.gov.uk/noise/goodpractice/hearingoverprotect.htm
  25. Accounting for 'real-world' factorshttps://www.hse.gov.uk/noise/goodpractice/hearingrealworld.htm
  26. Advice on issuing hearing protectionhttps://www.hse.gov.uk/noise/goodpractice/hearingadvice.htm
  27. Workplace designhttps://www.hse.gov.uk/noise/goodpractice/workplacedesign.htm
  28. Plastic productshttps://www.hse.gov.uk/noise/goodpractice/plastics.htm
  29. Overview - Wood workinghttps://www.hse.gov.uk/noise/goodpractice/woodworking.htm
  30. Saw millinghttps://www.hse.gov.uk/noise/goodpractice/sawmilling.htm
  31. Air turbulencehttps://www.hse.gov.uk/noise/goodpractice/airturbulence.htm
  32. Planing and mouldinghttps://www.hse.gov.uk/noise/goodpractice/planingmoulding.htm
  33. Overview - Concrete and cementhttps://www.hse.gov.uk/noise/goodpractice/concrete.htm
  34. General informationhttps://www.hse.gov.uk/noise/goodpractice/concretegeninfo.htm
  35. Avoiding impactshttps://www.hse.gov.uk/noise/goodpractice/avoidingimpacts.htm
  36. Music and entertainmenthttps://www.hse.gov.uk/noise/goodpractice/music-and-entertainment.htm
  37. Overview - Case studieshttps://www.hse.gov.uk/noise/casestudies/index.htm
  38. Full indexhttps://www.hse.gov.uk/noise/casestudies/fullindex.htm
  39. Sound solutionshttps://www.hse.gov.uk/noise/casestudies/soundsolutions/index.htm
  40. Overview - Resourceshttps://www.hse.gov.uk/noise/furtherinfo.htm
  41. Publicationshttps://www.hse.gov.uk/noise/publications.htm
  42. Researchhttps://www.hse.gov.uk/noise/research.htm
  43. Statisticshttps://www.hse.gov.uk/noise/statistics.htm
  44. Overview - Policy statementshttps://www.hse.gov.uk/noise/policy.htm
  45. Acoustic shockhttps://www.hse.gov.uk/noise/acoustic.htm

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Updated 2021-02-09