Print Email Facebook Twitter Balancing speech intelligibility versus sound exposure in selection of personal hearing protection equipment for Chinook aircrews Title Balancing speech intelligibility versus sound exposure in selection of personal hearing protection equipment for Chinook aircrews Author van Wijngaarden, S.J. Rots, G. TNO Technische Menskunde Publication year 2001 Abstract Background: Aircrews are often exposed to high ambient sound levels, especially in military aviation. Since long-term exposure to such noise may cause hearing damage, selection of adequate hearing protective devices is crucial. Such devices also affect speech intelligibility. When speech intelligibility and hearing protection lead to conflicting requirements, a compromise must be reached. The selection of personal equipment for RNLAF Chinook aircrews is taken as an example of this process. Methods: Sound attenuation offered by aircrew helmets and ear plugs was measured using a standardized method. Sound attenuation results were used to calculate sound exposure. Objective predictions of speech intelligibility were calculated using the Speech Transmission Index (STI) method. Subjective preference was investigated through a survey among 28 experienced aircrew members. Results: The use of ear plugs in addition to a (RNLAF standard) helmet may lead to a significant reduction of sound exposure. Using ear plugs that offer high sound attenuation, instead of using a less attenuating type, gives a little additional reduction of sound exposure, at the expense of a large reduction in speech intelligibility. Hence, it is better to use 'light' ear plugs. Better performance still is offered by Communications Earplugs, ear plugs featuring integrated miniature earphones. Results from the user preference survey correspond well with objective measurement results. Conclusions: In the case of the RNLAF Chinook, the best solution is using Communications EarPlugs in combination with a standard helmet. The Chinook case clearly illustrates that hearing protection and speech intelligibility should be treated as connected issues. Subject aviation Acoustics and AudiologyAircrews speech transmission indexCommunicationEarplugsHearing protectionNoise exposureSpeech intelligibilityairplane crewhearing impairmentlong term exposureperformanceprotective equipmentsoundspeech intelligibilityvalidation processAerospace MedicineEar Protective DevicesHearing Loss, Noise-InducedHumansMaterials TestingOccupational DiseasesOccupational HealthSpeech Intelligibility To reference this document use: http://resolver.tudelft.nl/uuid:b7896835-e211-4888-a280-5e32757c673a TNO identifier 10576 Source Aviation, Space and environmental Medicine, 72 (11), 1037-1044 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.