Abstract
This work is devoted to examine the effect of ambient temperature on limiting oxygen index (LOI), whose concept will be utilized to evaluate the safeness of the material bringing into the space environment, currently based on NASA-STD-6001 (TEST 1). For LOI test (= ISO 4589-2), flame spreads toward the downward, whereas for TEST1, flame spreads toward upward, therefore, the criterion for burning for both tests is not identical. Considering the fact that the upward spread is more preferable than downward spread, limiting oxygen concentration given by LOI test method may always over-predict the limiting oxygen concentration for TEST 1 configuration. To cover this discrepancy, the concept of Temperature Oxygen Index (TOI) based on ISO 4589-34) is newly demonstrated to elucidate the applicability to fulfill the current demand. As increase the field temperature, test material might be easy to burn so that limiting oxygen concentration would decrease even in downward spread test method (namely, LOI test method). It is found that increasing temperature results in linear decrease of LOT (minimum oxygen concentration to burn). More importantly, ABS, PC and PMMA shows almost the same decrease rate of LOI against the temperature increase. Further analyses are underway to explain this observed trend.
