| Popis: |
As data have accumulated indicating the difficulty in basing estimates of field‐delivered (i.e., real‐world) protection for groups of users upon classical laboratory‐derived optimum attenuation data, more attention has been directed towards standards intended to provide better simulations of the real world. The development of ANSI S12.6‐1997 Methods for Measuring the Real‐Ear Attenuation of Hearing Protectors, is one approach towards addressing this problem. The standard includes both experimenter‐supervised fit and subject‐fit methods. The latter method, designated as Method B, requires the use of audiometrically experienced subjects who are naive in the use of hearing protection. This method is intended to approximate the upper limits to the attenuation that can be expected for groups of occupational users. It yields mean attenuation values, more so for earplugs than earmuffs, that are substantially lower and standard deviations values that are higher than previously found using ANSI standards. This paper will present the latest Method‐B test data, review ongoing studies designed to further evaluate the Method‐B protocol, and will comment on efforts to more widely disseminate Method‐B data and the associated noise reduction rating (Subject FIT) [NRR(SF)] which can be derived from such values. |
