Abstract
Checks on factors in characterizing fire-hazard of several organic building materials with respect to the criterion on ignition and surface flame-spread have been pursued by radiation-predominant present JIS A 1321-type furnace and convection-predominant vertical furnace (used to be JIS A 1321-type furnace) and Madison tunnel-type furnace. Following measurement have been conducted particularly for plywoods in ISO-type furnace ;
1) relative rate of heat-produced or dQ/dt.
2) decomposition-rate or dW/dt. (dL/dt in tunnel-furnace)
3) smoke produced and its production-rate or dCA/dt.
4) temperature-disribution inside of the samples or T vs. thickness d.
5) radiation-intensity and temperature distribution on the surface of the samples in the respective furnaces.
Counter-charts representing the relations among those factors have been obtained and illustrated in the report for the further analysis on fire-hazard of the samples, which suggest the predominant effect of radiation from the fire-source in the furnace super-imposed on the convectional heat-transfer with respect to criterions on the ignition and combustion patterns of the samples. Secondly, distinctive difference concerning item 4 (based on the difference of the amount of heat-flux through the surface) have been recognized with the nearly same surface temperature between ISO-type furnace (presently available) and used to be JIS A 1321-type.
Thirdly linear relation has been observed between weight-loss of the samples or (W0−W )/W0 and sample-thickness d for a series of plywoods and coincidence has been recognized at d of ca. 12mm concerning the pattern on dQ/dW of test-samples vs. thickness d between present JIS A 1321-type and the convection predominant furnaces, which illustrated opposite patterns particularly for thin samples. Finally, similar patterns have been observed in dCA/dt vs. dQ/dW and dCS/dt vs. dQ/dW diagrams between present JIS A 1321-type furnace and Madison-type tunnel furnace (ASTM D E 286-69) for the surface flame-spread. We have reached to the following pattern concerning the fire-hazard of the organic building materials based on the above data ; dW/dt or dL/dt of the samples in the vertical and tunnel samples which are proportional to dQ/dt, will be dependent on the radiation-intensities through the surface of the samples.
Therefore, the appropriate setting of the measure of the radiation amount in the test-furnace corresponding to those as estimated by the respective phase in the modeling of fire will be the first preference in the criterion on the classification in the firehazard of organic interior building materials.
