The development of a REAT test facility and an evaluation of hearing protector assessment methods
| dc.contributor.author | Scott, Ben | |
| dc.date.accessioned | 2015-09-16T22:57:54Z | |
| dc.date.issued | 2015 | en |
| dc.description.abstract | This thesis is concerned with assessing the acoustic performance of hearing protection devices (HPDs). A facility was developed to assess HPDs in accordance with the real-ear attenuation at threshold (REAT) method described in AS/NZS 1270: 2002. The facility met all requirements of AS/NZS 1270: 2002 with the exception of the distortion requirements at low sound pressure levels. AS/NZS 1270: 2002 was reviewed by comparison to international standards and the literature, with consideration of the REAT test facility development. The maximum background noise levels in AS/NZS 1270: 2002 are considered to be too high and the specifications at low sound pressure levels are considered to be impractical. Revised maximum background noise levels and an alternative specification for the assessment of low sound pressure levels are proposed. The REAT, microphone-in-real ear (MIRE) and acoustical test fixture (ATF) HPD assessment methods were employed to assess conventional earplugs and earmuffs, a level-dependent earmuff, an active noise reduction (ANR) headphone and an abrasive blasting helmet using continuous noise and an insertion loss paradigm. The MIRE method showed the best agreement with the REAT method for conventional earmuffs. The ATF method was most useful for the assessment of the level-dependent earmuff and the ANR headphone at elevated noise levels. A field assessment method for HPDs was explored by instrumenting a single cup of a pair of earmuffs. The prototype device was used to assess the effect of safety glasses and a thin woollen helmet liner worn beneath earmuffs. The implementation was used to identify the variation in earmuff attenuation with noise from various directions and estimate the real-ear attenuation of an earmuff worn in combination with common field artefacts | en |
| dc.identifier.uri | http://hdl.handle.net/10092/10909 | |
| dc.identifier.uri | http://dx.doi.org/10.26021/2498 | |
| dc.language.iso | en | |
| dc.publisher | University of Canterbury. Mechanical Engineering | en |
| dc.relation.isreferencedby | NZCU | en |
| dc.rights | Copyright Ben Scott | en |
| dc.rights.uri | https://canterbury.libguides.com/rights/theses | en |
| dc.title | The development of a REAT test facility and an evaluation of hearing protector assessment methods | en |
| dc.type | Theses / Dissertations | |
| thesis.degree.grantor | University of Canterbury | en |
| thesis.degree.level | Doctoral | en |
| thesis.degree.name | Doctor of Philosophy | en |
| uc.college | Faculty of Engineering | en |
| uc.embargo | 24 | en |