O-089 The NIMIC Excel Worksheets on GAp Tests (NEWGATES)

August 2004
Frédéric Peugeot (Warhead Technology)

In recent years, NIMIC has been striving to encourage the use of small-scale testing in Insensitive Munitions assessments. Indeed, small-scale testing increases the ability and confidence of designers to understand, predict and, as a consequence, reduce the hazards associated with munitions.

Among the small-scale tests to be considered, is the gap test. This test is performed at many research & testing establishments in order to gauge the shock sensitivity of an energetic material using similar but not identical versions of the test.


As shown Figure 1, a gap test is composed of an inert barrier interposed between a standard donor explosive and a sample receptor/acceptor explosive under test. The thickness of the barrier is adjusted to establish a critical attenuator thickness for which the probability of detonation of the acceptor is 50%. By changing the donor, the confinement(s) or the barrier, dozens of gap tests have been created.

Figure 1


n additional complication has been introduced with the advent of insensitive energetic materials. Some of these products cannot be initiated in the conventional gap tests. Consequently larger and larger gap tests have been designed. As a consequence, to date, more than 30 gap tests have been defined and used either nationally or internationally. In order to assist the IM community to make the gap test as useful as possible, NIMIC has produced a software tool containing information related to ten of the most widely used gap tests. The names, attenuator and acceptor confinement materials and acceptor diameters of the reported gap tests are given in Table I.

Presentation details

This paper was presented at the Thirty-First United States Department of Defense Explosives Safety Seminar held on 24-26 August 2004 in San Antonio, TX, USA