Sources of Variation in Drop-Weight Impact Sensitivity Testing of the Explosive Pentaerythritol Tetranitrate

When new explosives are synthesized and developed, handling sensitivity must be measured in a consistent way to dictate safety protocols. Drop-weight impact tests, which represent explosive material sensitivity with the drop height required for a sample to react with 50% probability, are the most common method for understanding and quantifying explosive sensitivity. However, results from impact tests are influenced not only by the explosive material tested but also by the testing conditions and experimental setup. Examples of these testing conditions are the laboratory where the test was performed, the methods for choosing drop height levels and computing sensitivity, and whether grit paper was used to promote the initiation of reactions. We compile a historical data set with over 450 impact test results of the explosive standard pentaerythritol tetranitrate (PETN) from 1959 to 2020. We model the sensitivity of PETN as a function of the test laboratory, the test method, and the use of grit paper and find that all have a significant effect on the measured sensitivity of PETN. We validate the predictions from the fitted model with several new impact tests performed at Los Alamos National Laboratory.