既存オフィスビルのZero Water Building評価と節水効果の検証
雨水・排水再利用水の導入効果とLEED Zero Water評価
建物での水資源の循環を促すZero Water Building(ZWB)という概念が広まりつつある。米国のLEEDでは，水資源に対するネットゼロ評価としてLEED Zero Water認証が開始された。この認証は，水資源の確保のみ考慮された定義であるが，我が国においては災害時の水利用など，BCPの観点からもZWBの普及が重要となる。
そこで本報では，既存オフィスビルにおけるLEED Zero Water評価と設計に必要な単位給水量の把握や水利用に伴うCO2排出量の把握を目的に，水利用状況の調査を行った。その結果，雨水利用と排水再利用を導入することで，LEED Zero Waterが達成できた。これにより，LEED Zero Waterを目指すための単位給水量や節水効果，ランニングCO2排出量の低減効果を示すことができた。
キーワード：ゼロウォーター，LEED，節水，雨水利用，排水再利用
＊１ 技術センター 都市基盤技術研究部 空間研究室
Zero Water Building Evaluation and Water Saving Effect Verification of an Existing Office Building
Effects of Rainwater and Reclaimed Water Installations and LEED Zero Water Evaluation
The concept of Zero Water Building (ZWB) is becoming increasingly popular to promote the circulation of water resources in buildings. LEED in the United States has started LEED Zero Water certification as a net-zero assessment of water resources. Although this certification is defined only in consideration of securing water resources, in Japan, the spread of ZWB is also important from the perspective of business continuity plan (BCP), such as water use in the event of a disaster.
Therefore, in this study, we conducted a survey of water use in an existing office building for the purpose of LEED Zero Water evaluation and to determine the water supply units necessary for design and the CO2 emissions associated with water use. As a result, LEED Zero Water was achieved by introducing rainwater utilization and reclaimed water, and we were able to show the water supply units for LEED Zero Water certification, as well as the water saving and running CO2 emissions reducing effects of the net-zero water approaches.
Keywords: zero water, LEED, water saving, rainwater utilization, reclaimed water
*1 Valuable Space Research Section, Urban Engineering Research Department, Taisei Advanced Center of Technology