Last Uploaded: July, 2008

Tokyo Gas Kouhoku NT Building "Earth Port"

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Project Outline

Tokyo Gas Kohoku New Town building, which is called “Earthport”, was completed in March 1996, with a concept of “a life-cycle energy-saving office building”. It includes the idea of reducing the load on the global environment over the life of the building, from the time of its construction till the ime of its demolition. We intend to extend building life, while satisfying both energy saving efforts and interior amenities. The Building Core and other rooms such as office space are generally separated. In this case, the building core (stairs, elevators and halls) is connected to the showroom and it functions as an atrium which leads to each floor. This vertical wide atrium is called “Ecological Core”, because it is architecturally symbolic as well as working as the key factor for natural energy use systems such as natural lighting and natural ventilation, by chimney effect.

Basic Information

[CASBEE rank] S  (5 stars)
[CASBEE tool used] CASBEE for Existing Building (2004 edition)
[Location] 16-18 Chigasaki Chuo, Tsuzuki-ku, Yokohama
[Completion date]


[Site area] 2,499 m2
[Total floor area] 5,645 m2
[Structure] SRC
[Floors] 4 floors above ground / 1 penthouse floor
[Owner] Tokyo Gas Urban Development
[Designer] Nikken Sekkei Ltd.
[Contractor] Kumagai Gumi

Information for visitors

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  • Nikkei New Office Awards, Nikkei New Office Promotion Prize (New Office Promotion Association, 1996)
  • Good Design Award (Japan Industrial Design Promotion Organization, 1996)
  • 15th Superior Energy-Saving Equipment Awards, Prize of Excellence, New Construction Category (Japan Association of Refrigeration and Air-Conditioning Contractors, 1997)
  • 7th Environment and Energy Conservation Awards, Construction Minister's Prize (Institute for Building Environment and Energy Conservation, 1997)
  • Inter-Intra Space Design Selection, Design Award (Asahi Glass Co., Ltd., 1997)
  • 42nd Kanagawa Architecture Competition, Prize of Excellence (Kanagawa Prefecture, 1997)
  • 36th SHASE Awards of Technology, Category in Building Mechanical Service System (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, 1998)
  • Selected Architectural Designs of the AIJ (The Architectural Institute of Japan, 1998)
  • 2nd JIA Sustainable Architecture Award, Prize of Excellence (The Japan Institute of Architects, 2001)
  • 7th SHASE Award of Specialty, Ten Year Award (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, 2007)
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These cases are described based on assessment results obtained using CASBEE.
CASBEE is a method for rating the environmental performance of buildings using Building Environmental Efficiency (BEE) as an indicator, which is based on the results of separate scores obtained for Q-1~Q-3 (Quality) and LR-1~LR-3 (Load Reduction).