Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants|
Town planning/Architectural planning
|Research Institution||Building research Institute|
HAYASHI Yoshihiko Building Research Institute, Department of Fire Engineering, Chief Research Engineer, 防火研究グループ, 上席研究員 (70212157)
KATO Shinsuke University of Tokyo, Institute of Industrial Science, Professor, 生産技術研究所, 教授 (00142240)
OOKA Ryozo University of Tokyo, Institute of Industrial Science, Assistant Professor, 生産技術研究所, 助教授 (90251470)
SAGA Takeshi Tohoku Institute of Technology, Department of Architecture, Professor, 工学部建築学科, 教授 (50085437)
YUSA Shuitsu Building Research Institute, 防火研究グループ, 所付 (70344009)
NARUSE Tomohiro Building research Institute, Department of Research Planning and Management, Coordinator for International Research Cooperation, 企画部, 国際研究協力参事 (50237624)
岩見 達也 国土技術政策総合研究所, 都市研究部, 研究員
大宮 喜文 東京理科大学, 理工学部・建築学科, 専任講師 (10287469)
|Project Period (FY)
2002 – 2003
Completed(Fiscal Year 2003)
|Budget Amount *help
¥14,600,000 (Direct Cost : ¥14,600,000)
Fiscal Year 2003 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 2002 : ¥11,100,000 (Direct Cost : ¥11,100,000)
|Keywords||Urban Fire / Firebrand / Spot Fire / Fire Skip / Fire Wind Tunnel Experiment / CFD / CFD|
1.Purpose of the Research
This study was intended to perform fire wind tunnel experiments to elucidate the properties and behavior of firebrands produced from burning houses under a wind load and to develop a firebrand-based fire-spreading simulation model by combining the experiment results with the Computational Fluid Dynamics(CFD) technique.
2.Findings of the Research
(1)With regard to firebrand generation
A fire resistant house was constructed inside the fire wind tunnel facility at the Building Research Institute, Japan. Time-series measurements were conducted for quantity, shape, size, and other aspects of firebrands generated during a fire, systematically varying the speed of inflow wind and other parameters. Based on those results, the quantity of firebrands generated from a burning house under a wind load and other factors were generalized.
(2)With regard to the scattering of firebrands
A numerical simulation model was developed through modification of the Fire Dynamics Simulator(FD
S) of the National Institute of Standards and Technologies(NIST) to predict the firebrand scattering area. It was designed to deal with rapid thermal and density changes in a fire, as well as to take into account the drag and lift forces working on scattering particles. The model was subjected to full validation based on the results of a fact-finding survey of the firebrand scattering area in a fire that broke out at the Shirahama Spa, Wakayama prefecture. Cone calorimeter tests were also conducted using wood chips resembling firebrands to clarify the thermal behavior of scattering firebrands in terms of the heat generation rate and mass changes.
(3)With regard to the thermal damage potential of falling firebrands
In a post-earthquake situation in which roof tiles have usually fallen off of a structure, the spot fire risks become high because of the exposure of wooden materials used for roof structures. Given that, based on aerial photographs and field surveys performed of the city of Kobe after the Great Hanshin-Awaji Earthquake, the number of wooden buildings with fallen roof tiles was counted, classifying the level of structural damage. In addition, a general expression was proposed for predicting the shedding of roof tiles immediately after an earthquake. To clarify the spot fire behavior of roofs, fire wind tunnel experiments were performed using the shedding status of roof tiles and wind speed as parameters.
(4)Development of firebrand fire spread simulation model
A firebrand-based fire-spreading simulation model was developed by integrating the findings described in (1),(2) and (3) above. Case studies of actual built-up areas were also conducted. Less