To investigate the combusting behavior of fiber assemblies such as sleeping Futon, a small heat source was tested for the simulation of real cigarette. From the comparison of combusting behavior of real cigarette and that of simulated cigarette, the heat energy of real cigarette was estimated to be 16.6 kJ. This value was corresponded to the heat of combustion of one piece of cigarette observed by the use of bomb calorimeter.
The simulated cigarette was inserted between two sheets of small Futons, heating behavior was monitored by nine pieces of thermocouple for many conditions of heating energy to the extent of three times of above mentioned value and heating time of 15, 30 and 60 min, respectively.
The results were summarized as follows :
1) The temperature at the ignited front point along horizontal direction showed its maximum value in the early stage of heating. Contrary to this, the downward direction retarded most remarkably to reach the maximum value of temperature. Such order of position at which the time required for reaching the maximum temperature remained unchanged among nine positions (3 directions and 3 positions of cigarette) under the different conditions of heating. However, longer time was requested for reaching to that temperature under prolonged heating time for every measuring point.
2) Increases in area enclosed by the temperature curve and baseline indicating time were also observed as the functions of prolonged heating time and heat energy, respectively, and were to be especially enhanced in the downward direction at the center and rear ends.
3) On the other hand, either heating time or heat energy both gave little effects on the level of maximum temperature. This suggests that once fiber assemblies are ignited, the rising level of temperature is dominantly depended on the progress of smoldering of fiber assemblies rather than to the effect of heat source itself. The temperature at each position in each direction showed. their inherent upper limit. The lowest temperature was 450°C and the highest 600°C, respectively. Accordingly, these temperatures both exceed the ignition point of cotton and much hazards are involved which may occasionally turn to flaming combustion, causing fire.