The thoroughly investigated visual environment of the KI Building

Bird’s eye view of the KI Building

Fig.1 Bird’s eye view of the KI Building

Lighting of the office work space

Fig.2 Lighting of the office work space

The atrium of the KI Building

Fig.3 The atrium of the KI Building

    As a so-called “intelligent building” placing importance on creativity and activity in comfort, the KI Building (Kajima Corporation Headquarters No. 2 Building) has been completed in Tokyo’s Akasaka in February 1989 (see Figure 1). With one floor below ground and nine floors above, this building is not just office space: it is composed of an atrium and living-related space as well. As for its lighting as well, functionality and amenity harmonizing with local community and nature was investigated thoroughly.

    Lamp-exposure type white fluorescent luminaires widely were used in conventional buildings. Eeven though they met the JIS illuminance standard criteria, produced some issues such as discomfort glare , VDT syndromes , disharmony between amenity and energy saving , and so on. Given these circumstances, for creating an environment fitting for a place of creative activities, a new-look lighting system with the following features was used.

(1) To blanket an entire building with adequate brightness and spaciousness, natural light is guided deep into the offices by means of an atrium set in the center of the building (see Figure 3).
(2) As regards lighting of office space, discomfort glare was avoided by using fluorescent luminaires with louver furnished with high-output type dimmable electronic ballast (see Figure 2).
(3) By introducing an automatic lighting control system and a task-ambient lighting system (see Figure 2), energy saving including daylight usage was achieved and repair and maintenance was made easier.

 This lighting technology had a great impact on the way lighting was used in intelligent buildings. The nine engineers involved in this development—Shigefumi Yasutomi, Hiroki Kuchino, Naoharu Igarashi, and Shigefumi Kimura of Kajima Corporation, Sadao Takahashi, Tadahiro Kaneko, and Motoi Imajo of Toshiba Lighting and Technology Corporation, Masatomi Yamamoto of Kinden Corporation, and Nagayo Otani of Toko Electric Construction Company, Ltd.—received the “Japan Lighting Award” from the Illuminating Engineering Institute of Japan in 1989.

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