Characterization on Factor in Estimation Fire-hazardness by Furnace-test Based on the Patterns in the Modeling of Fire for the Classfication of Organic Interior Building Materials : Part (II)
Checks on factors concerning the surface flame spread rate and smoke-evolution of organic building materials by small inclined-type test furnace.

Abstract

Small tunnel-type test furnace of 85 cm length and 25 cm width with variable inclined angle was developed for the checks on the surface flame-spread rate and smoke-evolution with respect to the organic building materials as wood panels and plywoods.
Following results have been obtained for the stated purpose ;
A) Mean surface flame spread rate dL/dt and heat evolution rate dQ/dt were approximately propotional to cos^1/2θ and cos^1/4θ with respect to the inclination-angle of the furnace θ, where the plot of flame spread trends vs. time or mean dL/dt were approximated to be linear macroscopically.
B) Oscillative correspondence were recognized in the relations among smoke-evolution rate dC_s/dt, hest-evolution rate dQ/dt and weight-loss rate vs. flame-spread rate dL/dt.
Linear correspondence were also recognized in the relations among dC_s/dt, dQ/dt and dW/dt.
Smoke evolved C_s were proportional to heat evolved Q [deg·min] before the flame had been reached to vent-end (surface combustion area I), while C_s were inversely proportional to Q after the flame had been reached to vent-end (volume combustion to thickness-or Z-direction area II).
Above results will suggest the following pattern on factors concerning the surface flame spread of organic building materials as wood panels or plywoods ;
A) Dominationg factors on the mean surface flame spread rate of the above materials were the flame shape (lenghth and thickness) on test materials which were subjected and proportional to Reynolds number Re and total heat-transfer coefficient involving heattransfer by radiation from flame or h_X (=h +h_R ) for the system concerned in the laminar flow approximation. Secondly, decomposition rate of the material or Arrhenius term will support the acceleration of the spread which depends on the chemical nature of the materials.
B) Oscillative relations were recognized among factors representing the flame spread on the microscopic view-point or dC_s/dt, dQ/dt and dW/dt which were due to the oscillative heat equilibria induced successively by the competitive combustion among lenghth- or x-direction along the surface and those of thickness- or z-direction of the test samples.