A review of United Nations tests for explosivity

In attempting to develop a closed pressure vessel test for assessing explos ivity, arising from propagation of detonation, deflagration or thermal expl osion, some difficulties were encountered in relation to United Nations tes t methods. This led to a review of these methods and comparisons of their p erformance according to available data. The review supports the contention of several authors that the UN methods a re not optimal. Agreement between methods for a given property tends to be poor and some tests appear inherently unreliable. This is especially the ca se with the various vented pressure vessel tests, which are capable of both under- and over-estimating explosive potential depending on the particular circumstances. The need for improving the situation is clear and is highlighted by the cur rent move to a globally harmonised system for classifying dangerous materia ls. It is intended that such a system will cover storage and supply as well as transport. In the additional circumstances, reliable assessment of expl osivity is arguably even more important than in the transport situation. One step forward could be to introduce a closed vessel test. In the short t erm, however, such a test could only be introduced as a limited screen due to the vagaries of the current tests. (C) 1999 Elsevier Science Ltd. All ri ghts reserved.