The efficacy of earplugs at a major hazard facility

Abstract

At a major hazard facility, sporadic cases of occupational noise-induced hearing loss have occurred despite the use of hearing protection devices. Preliminary testing with a system for measuring personal attenuation ratings (PAR) suggested that earplugs may not achieve the attenuation implied by their Australian Class designation in eld-use conditions. We believe that ours to be a world-rst study at the time it was conducted to check the relationship between Personal Attenuation Rating (PAR) and the Australian SLC80 classi cation for hearing protection devices, and the ndings can be used to complement studies based on the American Noise Reduction Ratio (NRR). Methods:A cross-sectional study was performed with 65 volunteers. Participants were recruited from Operations and Maintenance Technicians at the major hazard facility. The participants had their PARs checked with different earplug types using the 3M TM E-A-R t TM system. An earplug is deemed to have achieved a 'pass' if it achieved 22 dB attenuation for 80% of users (the de nition for Australian Class 4 hearing protection) Results :None of the earplug types achieved the attenuation implied by their class rating when tested in eld-use conditions. There were statistically signi cant differences in the frequency of achieving a 'Pass', and in PAR, depending on earplug type. Roll-down foam earplugs may provide superior attenuation compared to pre-moulded earplugs. Conclusion:Earplugs are unlikely to achieve the attenuation found in laboratory conditions during eld-use.Personalised selection of hearing protection devices based on t-testing results should be encouraged. Key MessagesThe relationship between PAR and Australian SLC80 Class rating is consistent with what has been observed in the rest of the world when comparing PAR with other hearing protection device classi cations such as the American Noise Reduction Rating (NRR). HPDs underperform in eld-use conditions compared to laboratory ratings.

Noise levels at traffic intersections and awareness of noise pollution among traffic policemen and automobile drivers

“…25 Ear plugs need proper fitting for optimal sound attenuation and pre-molded ear plugs may not provide necessary attenuation in practical scenario. 26,27 Occupational noise exposure is often a neglected entity. There is a lack of awareness about this form of pollution among the stakeholders.…”

The use of the semi-quantitative classification method of assessment of the efficacy of safety systems for the railway technical rescue system

“…This depends on the complexity of the system or the principles of its operation, and in some cases, also on the available information. Examples of advanced efficacy estimation models were presented in detail, among others, in [2,6]. Which model should be selected (coincidence, diversification, reinforcement) depends on the relationships between the risk reduction measures within one subsystem or even subsystem subgroup.…”

“…A similarly good example of efficacy assessments, yet based on experimental research, is article [6]. It deals with the efficacy of personal protective equipment in the form of earplugs.…”