An evaluation and comparison of two psychoacoustic loudness models used in low-noise ventilation fan testing
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© 2017 The usage of loudness in standards and rating programs promoted by ASHRAE, HVI, and Energy Star is supported by the fact that occupants in buildings are exposed to noise from ventilating fans that are in close operational proximity to people. The current loudness calculation procedure, which is based on ANSI S3.4-1980 following a model by Stevens, is widely considered to be outdated because of its limited accuracy on equal-loudness contours, loudness-level-to-loudness conversions, and tonal components. Therefore, the study presented herein utilizes an extensive database consisting of 394 fan testing results to perform a detailed comparative analysis of this conventional Stevens loudness model and a revised loudness model developed by Moore et al. Although loudness results from each model were close to each other, a majority of fans under 2 sone show an overall larger loudness when the revised model is used for the noise calculation while there was no clear trend of noise differences for fans over 3 sone. These loudness differences between the two models are significant and would result in more fans failing certification if a revised loudness model is integrated into ventilation rating and certification programs. This effect on certification is more easily understood if one notes that less than a 0.5 sone difference in the certification limit would result in the same number of certified ventilating products presently conforming to Energy Star V4.0, at least for the large database evaluated in this study.
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