Particularly in workspaces and classrooms,В there is oftenВ less flexibility to reorient our point of view to avoid theВ sun.В SoВ why donвЂ™tВ we experienceВ glare walking in the park in bright daylight,В but as soon as we walk intoВ aВ building,В sunlightВ canВ becomeВ aВ very glaryВ light source?В Human visionВ can adapt toВ aВ wideВ range of luminous environments,В from very high ambient light levelsВ (i.e.,В outdoorsВ on a clear day) to very low light levelsВ (moonlight).В Visual discomfort occurs when the visual systemВ mustВ frequentlyВ switchВ its focusВ between relativelyВ dimmer interiorВ areasВ inВ ourВ visual fieldВ to high-brightnessВ areasВ (bright sun or exterior views).Дaylighting m etrics and t ools to a ssess v isual c omfort However, in the indoor environment,В sunlightВ canВ cause serious visual discomfortВ byВ seeingВ eitherВ the sun directly in the visual fieldВ or theВ excessiveВ light reflected off architectural finishes. Even without sunglasses,В peopleВ enjoy outdoor activity without serious visual discomfort because our visual system usesВ adaptiveВ mechanisms:В WeВ avoid directly viewing the sun, andВ reflexesВ inВ our irisesВ and eyelidsВ controlВ the amount ofВ lightВ admittedВ onto the retina. This lightВ is a fraction of incident light on the surface and depends onВ eachВ objectвЂ™sВ relativeВ reflectance value. The source of daylight is alsoВ immenselyВ bright,В andВ directВ viewingВ withВ theВ naked eye for more thanВ aВ few secondsВ could cause eye damage.В InВ anВ outdoorВ environment,В peopleВ experience sunlight indirectly through the reflection of lightВ off nearbyВ surfaces. Daylight is an inherentlyВ dynamic source-itsВ location and intensity changes with time of day,В seasons,В andВ weather.В ComparedВ withВ designing forВ electrical lighting, whichВ is static andВ makes itВ relatively easierВ toВ establishВ a lighting layout, designing for daylight requires aВ strategyВ that works across a wide variety of daylight conditionsВ andВ site-specificВ factorsВ (FigureВ 2). WhileВ there are many benefits to designing with daylighting in mind,В itВ also presents complex challenges. Additionally, daylight has incredible color-rendering propertiesВ thatВ canВ make the architectural finishes,В interior furniture, or artworkВ lookВ more vivid.В Providing daylightВ withВ windows alsoВ offersВ viewsВ to the exterior, which increasesВ occupantsвЂ™В productivity andВ satisfactionВ withВ the environment.В DaylightВ alsoВ canВ beВ usedВ to enhance the overall architectural experience due to its high color-rendering propertiesВ as a primary source of illumination to createВ aВ dynamic atmosphere (FigureВ 5). The health benefitsВ andВ theВ human desire forВ daylightВ areВ intuitivelyВ based on human evolution over the ages,В and thereВ isВ plenty of researchВ demonstratingВ the effect of daylight on human healthВ includingВ itsВ effect onВ ourВ circadianВ rhythm-theВ regulationВ ofВ ourВ sleep/wake patternsВ and other important biological processes. The energy codes and regulationsВ tend toВ focus on the energy-saving aspects of daylighting,В and often the visual comfort and occupant visual satisfaction is not part of the criteria.В IfВ measures forВ visual comfortВ are not considered, occupants will override the daylight system.В For example, an occupantВ could pullВ the shade down В as a result, the intended energy-savings goal will not be met.ДaylightВ alsoВ hasВ many subjective benefits that increase the quality of theВ interiorВ environment. Consequently,В someВ spaces lost their access toВ the outsideВ view, leadingВ toВ occupantsвЂ™В dissatisfactionВ due to losing their visual connection to theВ outside environmentВ andВ natural landscape.В UsingВ daylight has gainedВ more attentionВ recentlyВ becauseВ ofВ its significantВ benefits,В includingВ being the mostВ sustainable source of energy. The architectural layout ofВ significantВ preindustrialВ buildingsВ ensuredВ thatВ mostВ enclosed spaces had access to daylight to reduce the useВ of candles, oil lamps, orВ gaslight.В In the preindustrial era,В the daylighting design was based on the past experience ofВ theВ designer/builderВ or general guidelines.В The introduction of electrical lighting transformed the architecturalВ plan-without theВ necessaryВ access to daylight. Understand theВ daylightingВ design process is responsive to human visual comfort.Д«efore the advent of electrical lighting,В daylight wasВ the prominent source of illumination inВ buildings.Know what toolsВ and metricsВ can be usedВ to evaluate visual comfort.Learn about daylightingВ benefits andВ daylighting glare.

Visual interior tool