CIE 227

Abstract

Introduction Recently, energy conservation has become a global concern. Lighting is often the first thing to be turned off when electrical energy has to be conserved. For instance, after the Great East Japan Earthquake hit Tohoku Japan on March 11 in 2011, not only the quake-hit area but also the capital area, which used a large amount of electric energy, were demanded to reduce energy use. Turning off lighting and removing lamps are the most convenient measure for local municipalities and public transportation to demonstrate electric energy savings. Even without such an emergency situation, recent international, national and regional energy conservation codes have strictly regulated the maximum acceptable energy usage within a given unit of floor area and/or time. It may be easy to say that unnecessary lighting should be turned off or dimmed. While lamps emitting too much light for people with normal vision are removed or dimmed, illuminance levels required for older people and people with low vision have been neglected. These people often encounter difficulties in seeing obstacles and edges of steps in public and commercial buildings under lighting conditions dimmer than a few years ago. Current lighting requirements were established based on results of experiments that employed young subjects. In addition, a recent growing interest in global warming and a sustainable society has resulted in reduced illuminance requirements for the same visual tasks in global regulations and codes. Thus, it is important to summarize recommendations for lighting and visual components so that people with visual disadvantages will not have difficulties and problems when performing visual tasks in interior applications.