In this study, we looked into the method to establish fire growth rate by buildings use and to quantify Occupant density coefficient for growing fire at the beginning of a fire considering the characteristics of the combustibles and the Occupant density in a performance-based design. We also experim...
In this study, we looked into the method to establish fire growth rate by buildings use and to quantify Occupant density coefficient for growing fire at the beginning of a fire considering the characteristics of the combustibles and the Occupant density in a performance-based design. We also experimentally reviewed descent of smoke in a growth fire and analyzed the method to quantitatively predict flashover. In particular, smoke-logging phenomenon during sprinkling of water by a sprinkler was reviewed to establish a performance-based design plan considering the fire-fighting facility. Through such a result, the basic data for a performance-based design method was built. The detailed findings are as follows: (1) Design fire depending on the characteristics of the combustibles Actual condition survey and literature review were carried out for the fire load and exposed surface area of combustibles to establish design fire by domestic building use. As a result, a simplified prediction equation of fire growth rate which depends on fire load and weight of combustibles could be derived by calculating the relation between the fire load and the fire growth rate of an initial growth fire through investigation of combustibles by domestic building use. Also, the surface area coefficients of the combustibles in residential facility and business facility were presented respectively. It is presumed that the result derived here can be utilized as a simplified prediction equation which can be used to predict initial growth fire. (2) Occupant density by building use depending on design safety ratio In order to establish a quantitative design plan of a performance-based design, its relation with the number of fire events was derived using the result of the existing Occupant density, and the relevant design safety ratio was derived. As a result, a proposal of Occupant density was carried out classifying the design safety ratios into building uses for the Occupant density setting in accordance with the criteria to calculate the number of admittable persons in the domestic performance-based design standard. It is presumed that the performance-based design standard which is created by citing the standard of NFPA can be applied as a more accurate coefficient in the future during a performance-based design. (3) Verification test of design fire and review on growth fire As a result of comparing fire load and heat release rate to predict fire behavior, though a dynamic calculation could be carried out in the case that combustibles of 12 kg/m2 or less are laid in the section, no prediction could be made with a simple calculation in the case that the combustibles are more than that. However, in such a case, a regression equation could be derived through regression analysis of the relation between the density of combustibles and the maximum heat release rate, and the derived result of regression was reliable showing a coefficient of determination of 0.98. Also, as a result of analyzing the placement of combustibles and location of the ignition source, it was found that the influence of the materials of the combustibles and the materials of the combustibles adjacent to the ignition source is big. Though 4 different experiments were carried out for the evaluation, the result of comparing the findings with those of FGR model showed that the fire growth rate was similarly derived. Though flashover generally depends on the heat release rate and the temperature of the smoke layer, the result of analyzing its correlation with the smoke production rate showed that no flashover occurs even at high heat release rate if the smoke production rate is low, and the smoke production rate could be divided into three sections in the case that the synthetic polymer based material was the initial fire source. Accordingly, when predicting flashover, it is presumed that the smoke production rate is required to be evaluated together with the result of heat release rate. In particular, as a result of reviewing descent of smoke using the existing dynamic equation, it could be seen that the time that the critical human life height and temperature are reached is affected by the initial fire source and placement of combustibles. For this reason, when the evaluation is carried out concurrently with the temperature presented in the performance-based design, analysis is required to be made in accordance with the characteristics of the combustibles. (4) Analysis of smoke behavior in relation to smoke-logging phenomenon As a result of analyzing the characteristics of spray droplet by a sprinkler head using PIV equipment to build the basic data for close investigation of smoke-logging phenomenon, effective data for Sauter mean diameter, average particle speed, and spray amount could be obtained. As a result, it could be derived that spray amount and particle diameter have a linear relation in the tests conducted for three types of sprinkler heads excluding the residential head. Also, as a result of the test conducted for descending air current, it is presumed that a design fire scenario for which the effect of water spray by a sprinkler is taken into account should be applied without fail when carrying out a performance-based design as descending current of smoke layer stably takes place when heat release rate of 100 kW or higher appears, and descending air current occurs when the speed is 0.6 m/s or faster.
In this study, we looked into the method to establish fire growth rate by buildings use and to quantify Occupant density coefficient for growing fire at the beginning of a fire considering the characteristics of the combustibles and the Occupant density in a performance-based design. We also experimentally reviewed descent of smoke in a growth fire and analyzed the method to quantitatively predict flashover. In particular, smoke-logging phenomenon during sprinkling of water by a sprinkler was reviewed to establish a performance-based design plan considering the fire-fighting facility. Through such a result, the basic data for a performance-based design method was built. The detailed findings are as follows: (1) Design fire depending on the characteristics of the combustibles Actual condition survey and literature review were carried out for the fire load and exposed surface area of combustibles to establish design fire by domestic building use. As a result, a simplified prediction equation of fire growth rate which depends on fire load and weight of combustibles could be derived by calculating the relation between the fire load and the fire growth rate of an initial growth fire through investigation of combustibles by domestic building use. Also, the surface area coefficients of the combustibles in residential facility and business facility were presented respectively. It is presumed that the result derived here can be utilized as a simplified prediction equation which can be used to predict initial growth fire. (2) Occupant density by building use depending on design safety ratio In order to establish a quantitative design plan of a performance-based design, its relation with the number of fire events was derived using the result of the existing Occupant density, and the relevant design safety ratio was derived. As a result, a proposal of Occupant density was carried out classifying the design safety ratios into building uses for the Occupant density setting in accordance with the criteria to calculate the number of admittable persons in the domestic performance-based design standard. It is presumed that the performance-based design standard which is created by citing the standard of NFPA can be applied as a more accurate coefficient in the future during a performance-based design. (3) Verification test of design fire and review on growth fire As a result of comparing fire load and heat release rate to predict fire behavior, though a dynamic calculation could be carried out in the case that combustibles of 12 kg/m2 or less are laid in the section, no prediction could be made with a simple calculation in the case that the combustibles are more than that. However, in such a case, a regression equation could be derived through regression analysis of the relation between the density of combustibles and the maximum heat release rate, and the derived result of regression was reliable showing a coefficient of determination of 0.98. Also, as a result of analyzing the placement of combustibles and location of the ignition source, it was found that the influence of the materials of the combustibles and the materials of the combustibles adjacent to the ignition source is big. Though 4 different experiments were carried out for the evaluation, the result of comparing the findings with those of FGR model showed that the fire growth rate was similarly derived. Though flashover generally depends on the heat release rate and the temperature of the smoke layer, the result of analyzing its correlation with the smoke production rate showed that no flashover occurs even at high heat release rate if the smoke production rate is low, and the smoke production rate could be divided into three sections in the case that the synthetic polymer based material was the initial fire source. Accordingly, when predicting flashover, it is presumed that the smoke production rate is required to be evaluated together with the result of heat release rate. In particular, as a result of reviewing descent of smoke using the existing dynamic equation, it could be seen that the time that the critical human life height and temperature are reached is affected by the initial fire source and placement of combustibles. For this reason, when the evaluation is carried out concurrently with the temperature presented in the performance-based design, analysis is required to be made in accordance with the characteristics of the combustibles. (4) Analysis of smoke behavior in relation to smoke-logging phenomenon As a result of analyzing the characteristics of spray droplet by a sprinkler head using PIV equipment to build the basic data for close investigation of smoke-logging phenomenon, effective data for Sauter mean diameter, average particle speed, and spray amount could be obtained. As a result, it could be derived that spray amount and particle diameter have a linear relation in the tests conducted for three types of sprinkler heads excluding the residential head. Also, as a result of the test conducted for descending air current, it is presumed that a design fire scenario for which the effect of water spray by a sprinkler is taken into account should be applied without fail when carrying out a performance-based design as descending current of smoke layer stably takes place when heat release rate of 100 kW or higher appears, and descending air current occurs when the speed is 0.6 m/s or faster.
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