定差図法による建物火災の延焼速度式 (ロジスティック曲線) に関する基礎的研究

概要

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In this paper, we consider of the finite difference graphical method for deciding the coefficient of the fire spread formula (logistic curve) concerning to general building fires. The results which were analyzed are showed bellow. (1) The finite difference graphical method was proved to be very useful as an approximation by computing real cases. (2) By the cases of K city and S city, the coefficients a and c of the fire spread formula was indicated to be the function of wind velocity v and area of building G. (3) The modification of the logistic curve is done by equation (4-2). The ratio of the quantity of modification n_1ε_0 to G become under 8 percent. (4) At spreading of fires to neighbouring houses, pitch of buildings, structure of buildings-surroundings, trees, etc. become the resistance to spread of fires. The value of r which defined by the resistant coefficient R(=G^r) in the equation (3-9) is changable according to city types or city characteristics. For example, in the case of K city or S city the value of r is nearly equal to 0.40 under the wind velocity v=2.5(m/sec). (5) The ratio β_j of A_H to A_K or A_S is shown equation (4-8). In the case of K city the ratio β_K is nearly equal to 6.9 from 1.3 and in the case of S city β_s is nearly equal to 5.7 from 3.6 under the conditions of v=0〜7(m/sec) and G=100〜600(m^2).
1983-03-30