In the year of 2000, 36 cases of fire were turned up through the investigation on the fire safety in "SILVEER PEER", the collective housings for elderly people managed by Tokyo Metropolitan Government. In the latest study, we pursued the further investigation and found out that only 32 of those cases were the real fires. We interviewed the supervisors of "SILVER PEER" and learned the followings : (1) Under the consideration of the number reported to the firehouse, fire occurrence ratio at "SILVER PEER" is comparable to that in common apartment houses. (2) Most of the fires happened in the kitchen while the residents were cooking. The fires occurred because the pans were left unattended on the stove and their clothes were easier to catch on fire. (3) Most of the fires broke out around noon or towards evening while the residents were preparing for meals. (4) Because of the failure in hearing, the elderly are more likely not to notice the fire alarm when a fire occurred. In order to create the safe living environment for the elderly, it is important to take measures as followings to prevent fire breaking out and to extinguish them quickly. Firstly, it is very important to add the safety systems to cooking equipments and recommend the residents wearing incombustible clothes during cooking. Secondly, support system between the residents and the resident' s association is needed to take the effective preemptive behavior. Regular fire drills will help residents construct the network system and learn the appropriate action on fire.
Thermogravimetry is a popular analytical method for investigating thermal decomposition mechanism of solid material. From data obtained by thermogravimetry, the activation energy and the frequency factor of decomposition reaction can be derived easily if the material is decomposed through a single reaction. However, it becomes harder when several reactions occur when the material decomposes. In this study, we chose PMMA as a sample solid, which decomposes thermally through four elementary steps. The analytical method to derive the activation energy, the frequency factor, and the decomposition fraction of each elementary step was discussed.
To evaluate flame retardation effects of bromic retardant, thermal degradation mechanism of PMMA with TBBA was studied quantitatively by using thermal analysis. TBBA was believed to have enhanced effect when mixed with Sb2O3, so PMMA with TBBA and Sb2O3 was also studied. TBBA suppressed thermal degradation at lower temperature when added TBBA amount exceeded a threshold value, but promoted thermal degradation at higher temperature. From chemical point of view, the most suitable amount of TBBA addition is considered as ca. 15wt% when TBBA solely added and ca. 10wt% when TBBA and Sb2O3 added simultaneously. Gaseous bromic substances were not observed when TBBA solely added or TBBA added with Sb2O3 at concentration under 10wt%.