O-206 TNT and Blast Equivalency Characterization of Energetic Materials
When dealing with energetic materials, TNT Equivalency is commonly used for different purposes. For scientific purposes, it is a means to compare the explosive effects delivered by different energetic compositions, by expressing them in terms of an equivalent TNT detonation. Therefore, we need a set of accurate TNT equivalence values for the effects we are considering and, if relevant, at different distances. For safety purposes on the other hand, we need conservative, but reasonable values, and if possible, standard ones for the various energetic materials and the munitions in which they occur.
This paper first describes the most commonly used methods to determine TNT equivalences from a detonating charge: from theoretical methods to experimental ones including blast measurements. The available methodologies are presented and discussed. For cased charges, it is more difficult to determine TNT equivalences due to energy consumed by fragmentation and acceleration of fragments. This phenomenon depends on the confining material and its thickness.
In a second part, we present the results of a review on blast equivalency tests for propellants and pyrotechnics which are not designed to detonate. The main conclusion of this study is that there is currently no common agreement on the methods used to determine blast effects and consequently, to determine TNT equivalency. The ongoing work at MSIAC aims at gathering the studies on this subject and proposing a kit of best practices and lessons learnt for the benefit of the IM community.