Help us to improve the website - give your feedback.

Accounting for 'real world' factors

It is very likely that under conditions of real use, hearing protectors will give lower protection than predicted by manufacturers' data which is obtained from standardised tests. The difference between manufacturers' data and 'real-world' protection is due to factors such as poor fitting and wearing of spectacles or other personal protective equipment. You should account for this 'real world' protection by 'derating' the protector by 4 dB. This means, having followed one of the standardised methods for calculating the attenuation provided by a hearing protection device, assume that the sound level at the ear when hearing protection is worn will be 4 dB higher than would be predicted by the method. In this way you will get a better indication of the protection that users are most likely to get, and can select appropriate hearing protection accordingly.

The derating does not apply to the assessment of hearing protector performance against peak noise.

The 4 dB derating described above is regarded as an appropriate factor to bridge the gap between manufacturers' data and real-world factors, without introducing further complexity to the prediction of hearing protector performance. You will still be able to select an appropriate hearing protection device for the character of the noise, and hearing protectors that show better repeatability in standardised tests will still be distinguishable.

The use of a derating factor will not necessarily mean that you will need to select a protector with a higher rating than one you currently use. By following all the guidance in Part 5 of L108[46] you should be able to ensure that even if wearers get better protection than that predicted by these methods, the protected level at the ear will be within the recommended range.

You may wish to demonstrate by means other than relying on manufacturers' data and the methods outlined in this book that the hearing protection you supply meets the requirement to reduce the noise level at the ear to the appropriate level, eg by measurement of noise levels underneath hearing protection devices in conditions of real use.

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
  46. Part 5 of L108https://www.hse.gov.uk/pubns/books/l108.htm
  47. Noise calculatorshttps://www.hse.gov.uk/NOISE/calculator.htm
  48. Noise: Don't lose your hearing https://www.hse.gov.uk/pubns/indg363.htm
  49. Noise at work: A brief guide to controlling the riskshttps://www.hse.gov.uk/pubns/indg362.htm
  50. Hearing loss - what's it like?https://www.hse.gov.uk/NOISE/assets/video/index.htm

Is this page useful?

Updated 2021-02-11