Archive for November 2013

Assessment of Explosives in Squibs

Lutz Kurth, Holger Krebs, Benjamin Theil, Olaf Mücke, Christian Lohrer

Abstract: Experiments in this study reveal that the initiating capability of commonly used squibs is not high enough to initiate PETN in all cases. The fulfilment of the ‘new’ essential safety requirement 4 as set out in the European directive 2013/29/EU and the categorization of squibs as theatrical pyrotechnic articles (T2) can therefore be justified, as the explosive investigated belongs to quite a sensitive type (initiation with low impulse energies possible). Underwater initiating capability tests according to EN 13763-15 led to meaningful results, showing that squibs are usually unable to initiate a secondary explosive. For a general assessment of the initiating capability of squibs and comparable (theatrical) pyrotechnic articles a threshold range of an equivalent initiation capability in grams of PETN on the basis of the performed underwater initiating capability tests was determined. It was found that squibs are generally not capable of  initiating secondary explosives if the underwater initiating capability test showed an equivalent initiation capability below 0.25 g PETN. As a consequence of this result, the underwater initiating capability test gives an effective and safer alternative to the experimental confirmation of the
‘new’ ESR 4 by direct contact of the article with the secondary explosive and should then be preferred to it.

Keywords: Squibs, ESR 4, PETN, underwater initiating capability, EN 13763-15

Ref: JPyro, Issue 32, 2013, pp57-66 (J32_57)

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