REPENSANDO O PROJETO DE ILUMINAÇÃO:

AVALIAÇÃO DE MÉTRICAS DE LUZ CIRCADIANA

Abstract

During the last fifteen years, the research about mechanisms that set the relations between architectural lighting and circadian regulation processes in the human body grew in production. However, little progress has been made in applying these concepts to architectural design practice. There are just few examples and theirs impacts evaluation are not clear. The problem is related with the discovery, in the 2000´s, of the photoreceptor in the human eye (ipRGC) and its direct relation with the light-dark cycle, not only with the vision processes, but also in the physiological processes (circadian rhythms). The available design methods are focused on visual comfort and do not meet needs related with circadian regulation. This article pursues to compare two circadian lighting metrics with visual tasks performance requirements for an architectural space. Equivalent Melanopic Lux and Circadian Stimulus were the circadian lighting metrics evaluated. The methodology covered case study (hypothetical office) through computer simulation (DIALuxEvo8). Two calculation illuminance plans with a standard grid were used: a work plan (horizontal illuminance), according ABNT NBR ISO/CIE 8995-1; and at the observer`s plan (1,20m) with vertical illuminance calculation according circadian lighting recommendations. Differences were identified between the spectral sensibilities’ functions and conversion methods. We also concluded, as expected, that the visual requirements do not meet health requirements considering the design methods. The purpose of the study was to highlight the circadian lighting metrics` impact in the lighting design process and current standards, contributing with the discussion about lighting quality.