Investigation of Celotex trademark charring depths in the DT-18 shipping container

Celotex {trademark}, the insulating material used between the outer and inner containers of the DT-18 shipping package, undergoes decomposition, combustion, or both when heated to temperatures exceeding 150{degrees}C. Several DT-18 packages that had previously undergone hypothetical thermal accident testing were opened and Celotex {trademark} charring depths ranging from {1/2} to 1 {1/2} in. were recorded. The majority of char depth data taken was between 3/4 and 1 {1/4} in. One-dimensional HEATING 7.1 models of the DT-18 package were developed. HEATING predicts charring depths of 1 to 1 1/8 in., which are in good agreement with measured values. Both experimental and analytical data indicate that charring is fairly uniform over the DT-18 package. 7 refs