濡れたネットによる施工現場の暑熱環境緩和に関する研究

実測調査による暑熱緩和効果

梅田 和彦^＊１・矢島 清志^＊２・杉山 由子^＊２・奥畑 浩一郎^＊２・守田 進^＊３・寺崎 透^＊４・伊藤 永三郎^＊４

我が国の大都市では，ヒートアイランド現象が大きな社会問題となっている。特に，大阪は真夏日や熱帯夜の日数が東京や名古屋よりも多く，ヒートアイランド現象が全国で最も深刻な場所で，熱中症患者の搬送者数も毎年100人を越えている。建設工事現場においても，作業員の健康管理のための屋外暑熱対策が重要である。
本研究では，大阪市で最もヒートアイランド現象が深刻な地域にある施工現場において，屋外暑熱環境の緩和を目的として施工環境の改善を試みた。実施した対策は，仮囲いの内側の安全通路に設営した高さ3ｍで長さ73ｍの工事用ネットを，掘削工事で汲み上げた地下水で全体的に濡らして気化熱で暑熱緩和する方法（水のカーテン）である。2008年9月に現地で測定調査した結果，水のカーテンで安全通路の気温が約1.5℃低下し，体感指標のSET*も約1.5℃低下したことを確認した。

＊１ 技術センター 建築技術開発部 建築生産技術開発室
＊２ 関西支店 積水ハウス御堂筋本町ビル新築工事作業所
＊３ 関西支店 建築部
＊４ 建築本部 建築部

Investigation on Mitigation of the Thermal Environment in Construction Sites by Wetted Nets

Field Measurements of the Evaporative Cooling Effect

Kazuhiko UMEDA^*1, Kiyoshi YAJIMA^*2, Yoshiko SUGIYAMA^*2, Koichiro OKUHATA^*2, Susumu MORITA^*3, Toru TERASAKI^*4 and Eizaburo ITO^*4

The heat island phenomenon is a severe social problem in large Japanese cities. The problem is most serious in Osaka, where the number of hot summer days and tropical nights is greater than in Tokyo or Nagoya. Every year in Osaka, more than a hundred emergency patients suffering from heat stress disorders are carried to hospitals by ambulances etc. From the viewpoint of health care of field workers, it is important to mitigate such hot urban micro-climatic environments at building construction sites too.
The purpose of this study is to mitigate the hot climatic conditions during construction work at a site located in Osaka City. At this location, heat island effects are known to be most serious even within Osaka City. The hot urban micro-climatic environment was mitigated by creating a “water curtain” around the construction site. This was achieved by spreading nets (3 meters in height and 73 meters in length) inside the perimeter fence and then discharging the groundwater generated during the construction work via these nets. In September 2009, field measurements were conducted at this site. It was found that because of the presence of the “water curtain”, the air temperature inside the safety passages as well as the Standard New Effective Temperature SET^* (which is an index of the thermal environment), tended to be reduced by about 1.5 degrees Celsius.

*1 Construction Technology Development Section, Building Technology Development Department, Technology Center
*2 The Sekisui House Midosuji Honmachi Building Project, Kansai Branch
*3 Building Construction Department, Kansai Branch
*4 Building Construction Department, Building Construction Division

48 - REPORT OF TAISEI TECHNOLOGY CENTER No.42 2009