Evaluation of environmental noise based upon the percentage of dissatisfied

This article is a proposal and aims to be a first step to develop a method to evaluate and classify environmental noise, according to EN‐15251 and CR‐1752, in the built environment based on the percentage of dissatisfied related to the equivalent background noise level.

In the European guideline CR‐1752 and the standard EN‐15251 three categories of the indoor environment in buildings are prescribed (category A, B and C). In the recommendations, the limit whereby the percentage of dissatisfied should remain under varies in each category for both the thermal indoor environment and the air quality. The categories for noise and illumination criteria are not yet explicitly related to a percentage of dissatisfied.

Using the percentage of dissatisfied as the evaluation criterion, when related to the equivalent background noise, produces a more refined evaluation of comfort than an evaluation based on the percentage of seriously disturbed or the effects of sleep deprivation in relation to external noise. Furthermore, this corresponds to the European standards and recommendations concerning quality classification of the indoor environment, based on the percentage of dissatisfied.

Based on recent European undertakings concerning the development of categories for the indoor environment based on the percentage of dissatisfied, it is desirable to utilise these categories to noise aspects too, and to relate it to the equivalent background noise level.