In fire spread through RDF (Refuse Derived Fuel) or wood-pellet packed bed, the color of layer gradually changes by charring or combustion. A cross section which fixed layer in gypsum was observed in order to clarify the structure of combustion zone in the fire spread (smoldering). Temperature profiles, aspects of discoloration and charring were examined experimentally. In the method by gypsum solidification, color (brightness) image processing is desirable for RDF and wood pellet, because change of color is more sensitive than volume for heating. Wood (Western hemlock) cut in cylindrical of 15 mm (D) and 37 mm (L) was used as a sample. The direction of fire spread was made to be upward and downward. As a result of the experiment, it was found that the thickness of discoloration region was respectively 23 mm and 33 mm in the upward fire spread and the downward fire spread. Though it is shown that the method of this study is useful, it is necessary to measure temperature of gas phase and solid phase in a packed bed simultaneously in order to clarify the structure of combustion zone.
It is necessary to estimate the efficient water discharge performance to a burning area of fire with considering the water delivering characteristics. The objective of this study is to develop the two-dimensional simple numerical simulation model and to evaluate discharge ability of water that is discharged like a rod by a fire fighter hose nozzle. The simulation model based on MPS method have been constructed with considering the breakup model for the discharged water applying the Rosin-Rammler distribution to estimate the diameter distribution of water droplets. The quantitative evaluation method for the discharge ability has been established by analyzing the distribution of the water volume dropped on the surface as footprint (or landing zone). We conducted the small scale water discharge experiments (3.7 L/min by 0.05 MPa) in order to evaluate quantitatively the simulation model. The maximum range and maximum height of the discharged water are simulated well with less than 4 % difference in comparison with measured data.
Fire resistant tests are conducted on full scale specimens of wooden wall that sets up wooden-based board on heating side were carried out. The furnace at Tokyo University of Science was used. As the result of experiments, the temperature of each part of the wall was not able to confirm a remarkable difference by the wood species and installation method. But increase in board thickness and fire retardant treatment brings the delay of the temperature rise. The temperature rise of unexposed surface of wooden-based board became rapid after it reached 260°C. The time which temperature of exposed surface of plywood reached 260°C was 1～4 minutes later than the time which temperature of unexposed surface of wooden-based board reached 260°C.
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