Presentation on theme: "Noise and Hearing Loss in the Metal Manufacturing Industry David Welch Gareth John Alla Grynevych Peter Thorne."— Presentation transcript:
Noise and Hearing Loss in the Metal Manufacturing Industry David Welch Gareth John Alla Grynevych Peter Thorne
Day 1: Tour of facility Employees interviewed individually - Explanation of project - Interview - Disposable earplug assessment (Veri-Pro) Sound level meter measurements Day 2: Hearing tests (otoscopy, tympanometry, and audiometry) Dosimetry Research Protocol
Impulse Noise Top Ten RankSource of impulse noiseMean Lpeak (dB(C)) 1 Dropping sheet steel onto surface of an ArcWriter machine 141.5 2 Sledge hammering a mild steel girder 139.6 3 Dropping a steel bar onto a concrete floor from approx 0.5m 138.6 4 Dropping a steel bar onto a concrete floor from approx 0.5m 137.5 5 Sledge hammering a steel plate on a metal work surface 132.3 6 Dropping sheet steel on top of other sheet steel from approximately 1m 131.8 7 Hammering (ball-pein hammer) a galvanised steel sheet, on a metal work surface 129.3 8 Rolling over a steel girder, on a metal stand 127.8 9Centre punching a steel girder125.3 10 Dropping a large, hollow, aluminium tube onto concrete floor from approximately 1m 124.7
The mean age was approximately 40 years. Age (years)
Audiogram Notch Criteria: 1.Poorer threshold at 4 or 6 kHz than at 2 kHz AND 2.Better threshold at 6 or 8 kHz than at 4 kHz AND/OR 3.Better threshold at 8 kHz than at 6 kHz AND 4.Notch depth >20 dB HLAND 5.Bilateral notches
Audiogram Notch 15 people had bilateral notches according to the criteria – 0/40 (0%) 18-30 years – 4/39 (10%) 31-40 years – 6/54 (11%) 41-50 years – 5/27 (19%) 51 years or more
Hearing Disability vs Hearing Loss Ability to hear in noisy backgrounds was impaired in 25% of participants
Tinnitus Amount of tinnitusNumberPercent (UK males ages 18-80) Never1066665 Up to 5 minutes2214 28 Rarely1811 Half the time111 Most of the time532 All the time854 Responses to the question: In the last 12 months, when you are awake and it is quiet, have you experienced tinnitus...?
Hearing Protection 160 workers interviewed 86 (54%) used earmuffs 75 (47%) used earplugs 13 (8%) used either 12 (8%) used neither (Of these 12, 5 were production workers with Leq scores : 89.7, 86.6, 84.2, 81.9, and 71.6 dB(A). )
Lifetime Noise Exposure without HPE (Overall, there was a correlation between age and years spent working in noise without HPE (r=0.480, p<0.001))
Conclusions High noise levels in metal manufacturing Half of production workers exposed >85dB(A) NIHL was not widespread (15/160 with measureable notch) Hearing disability was present in a quarter of workers – but not well linked with hearing loss HPE used by almost all production workers HPE used always by younger workers (up to approximately 40 years) Suggestive of greater awareness of the impact of noise in younger workers Poor fitting of foam earplugs was common Poor fitting of foam earplugs was associated with NIHL
Acknowledgements Thanks to the many companies and individuals who gave their time to participate in this research. Thanks to Dr John Wallaart, ACC Programme Manager, for his friendly advice and assistance. Thanks to John Skudder, ACC Workplace Safety Programme Manager, for his invaluable help in getting the research started and for sharing his knowledge along the way. Thanks to Zaneta Schumann, Department of Labour Service Manager, and the Auckland North Office of the Department of Labour for their kind help and interest in the research. Thanks to Sperian for the generous loan of the VeriPro system.