Statistical Analysis of an Inter‐Laboratory Comparison of Small‐Scale Safety and Thermal Testing of RDX

The Integrated Data Collection Analysis (IDCA) program has conducted a proficiency test for small-scale safety and thermal (SSST) testing of homemade explosives (HMEs). Described here are statistical analyses of the results from this test for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of the RDX Class 5 Type II standard. The material was tested as a well-characterized standard several times during the proficiency test to assess differences among participants and the range of results that may arise for well-behaved explosive materials. The analyses show there are detectable differences among the results from IDCA participants. While these differences are statistically significant, most of them can be justified for comparison purposes to assess potential variability when laboratories attempt to measure identical samples using methods assumed to be nominally the same. The results presented in this report include the average sensitivity results from the IDCA participants and the ranges of values obtained. The ranges represent variation about the mean values of the tests of between 26 % and 42 %. The magnitude of this variation is attributed to differences in operator, method, and environment as well as the use of different instruments that are also of varying age. The results appear to be a good representation of results generated by the broader safety testing community based on the range of methods, instruments, and environments included in the IDCA proficiency test.