Yoshikazu Deguchi

Statistical Estimations of the Distribution of Fire Growth Factor - Study on Risk-Based Evacuation Safety Design Method

YOSHIKAZU DEGUCHI, HIROAKI NOTAKE, JUN’ICHI YAMAGUCHI, and TAKEYOSHI TANAKA Research & Development Institute Takenaka Corporation 1-5-1 Ohtsuka, Inzai-city, Chiba, 270-1395, Japan Institute of Technology Shimizu Corporation 3-4-17 Etchujima, Koto-ku, Tokyo, 135-8530, Japan Technical Research Institute Obayashi Corporation 4-640, Shimokiyoto, Kiyose-city, Tokyo, 204-8558, Japan Disaster Prevention Research Institute Kyoto University Gokasyo, Uji, Kyoto, 611-0011, Japan

Statistical Analysis on the Reliability of Sprinkler Systems: Study on a Risk-Based Evacuation Safety Design Method

To evaluate the importance of fire protection systems objectively in evacuation safety planning of building fires, authors have proposed a methodology for selecting both design fire scenarios and design fire simultaneously for performance-based fire safety design according to acceptable evacuation risk in fire, which we call risk-based evacuation safety design method or R-B ESDM in abbreviated term. An important factor when using the R-B ESDM is to set the reliability of sprinkler systems. Although several studies exist on the reliability of sprinkler systems, there is no study that looks into the relations of design fire and design fire scenarios. In order to introduce the reliability of sprinkler systems to R-B ESDM, the data of the national fire reports have been statistically analyzed by classifying the fires in the sprinklered spaces into three patterns: “fires that sprinklers extinguished,” “fires that sprinklers suppressed,” and “fires that sprinklers failed to control.” The probabilities of the three patterns have been calculated by using the number of fires according to the burned area. As a result, if the burned area for effective suppression is defined as less than 4 m2, the reliability of effective sprinkler activation turns out to be approximately 83 %.

Verification Methodology of Vertical Fire Spread to the Upstairs Room via Openings and Facade Wall

The authors conducted an ISO 13785-2 modified large-scale facade fire tests in Tokyo University of Science and tentatively proposed the draft for the calculation method for vertical upstairs fire spreading based on those fire test results, prior to this study. And in this research, several modifications were carefully added to past calculation methods, especially regarding the calculation of temperature in the fireroom, detailed method of unifying multiple openings on the same floor for calculation, and the criteria for the occurrence of upstairs fire spreading. Detailed calculation methods are proposed for two different situations depending on the existence of an eave above the opening at the fireroom, respectively. Also, two different criteria for verification of vertical upstairs fire spreading were proposed, one of which is based on the maximum heat flux to the upstairs room (Method 1), while the other is based on the integrated value of heat flux over time of fire duration (Method 2). Using this newly modified calculation method, the effectiveness of 90 cm spandrel and 50 cm eave is demonstrated, respectively, in terms of practically preventing the occurrence of vertical upstairs fire spreading. Improved verification calculation methods (both Methods 1 and 2) are applied to four exiting office buildings in Japan and seven rooms of fire origin considered. Verification methods using calculation proposed in this study are proved to be able to practically evaluate the occurrence of vertical upstairs fire spreading, especially regarding noncombustible facades with openings in there.

Evaluation of Temperature Rise Under an Eave Due to Flame Impingement: Toward the Mitigations of Fire Spread Risk in Japanese Historic Urban Areas

Flame spread along eaves has been one of the major causes of fire spread for Japanese historic urban areas. For the fire safety assessment of such an environment, this paper investigates basic characteristics of heat transfer under eaves due to flame impingement. A series of model experiment was conducted measuring temperature rise and incident heat flux under nonflammable eaves with varying parameters on burner geometry, burner installation position, and fuel supply rate. Flow behavior under an eave was analyzed following the approach of the classical plume theory. The analysis result showed that the temperature rise is constant in the flaming regime and decreases proportionally to the distance to the power of −1 in the nonflaming regime. Reasonable correlation was obtained with the experimental results; the correlation was better when using the distance along trajectory from the burner as the reference length scale, rather than the distance from the impingement point.

An Experimental Study on the Mass Flow Rate from a Line Fire Source Along a Vertical Wall

Flame height, heat flux to the wall surface, centerline temperature rise, and mass flow rate from a line burner along a vertical wall were measured to propose an experimental correlation for mass flow rate previously not established. The heat release rates and burner heights were changed for three burners of lengths 0.2 m, 0.3 m, and 0.5 m. The intermittent flame heights and heat flux to the wall surface were consistent with experimental correlations of an earlier study by Hasemi. The centerline temperature rise in plume region was inversely proportional to the distance from the fire source, consistent with the theoretical analysis. The horizontal temperature distribution in the plume region was consistent with a Gaussian distribution. The mass flow rate was proportional to the distance from the fire source. The entrainment coefficient appears to be consistent with earlier studies for line plumes in an open space.

Experimental Study on Confluence of the Emerged Flames Ejected from Two Adjacent Openings

A considerable number of studies on emerged flames have been done in the past. However, since these studies were implemented using a single opening, the same conditions applied to multiple openings in close proximity to each other are yet to be determined.