Steel sleeve test

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The steel sleeve test (also known as the Koenen test ) characterizes the behavior of a substance (usually an explosive ) in relation to thermal stress. The criterion here is that a steel sleeve filled with the substance is destroyed under the action of a defined thermal load in an explosion with a defined fragment pattern. The test method was developed by H. Koenen and further developed by the Federal Institute for Materials Research and Testing (BAM).

Test method

The basic principle of the test method is based on the fact that the substance to be tested is thermally loaded in a steel sleeve that is closed with a nozzle plate with a variable relief opening. The explosive decomposition of the test substance must be so violent that the steel sleeve is destroyed as a result of a sudden pressure effect due to the release of highly stressed gases despite the presence of a relief opening. In a seamlessly drawn, cylindrical steel sleeve with an inside diameter of 24 mm or outside diameter of 25 mm (i.e. a wall thickness of 0.5 mm) and a height of 75 mm, sample substance is filled up to a filling level of 60 mm. The steel sleeve is then closed with a nozzle plate with a central, circular bore with a defined diameter. The nozzle diameter can vary from 1 mm to 20 mm. A nozzle diameter of 24 mm corresponds to the open steel sleeve. The thermal load takes place by heating the steel sleeve in a combustion chamber equipped with four Bunsen burners, a temperature range of 700 ° C to 800 ° C being reached within one to two minutes. A dismantling of the sleeve into at least three parts is considered a positive result in the sense of an explosion.

Classifications

In terms of the Explosives Act and Regulation (EC) No. 440/2008 of the European Commission, a limit diameter of 2 mm applies, above which it is classified as an explosive substance . The limit diameter is determined by varying the nozzle diameter. In addition to testing for friction sensitivity and impact sensitivity , the steel sleeve test is one of the tests prescribed by the Explosives Act.

Examples

Substances with high thermal sensitivity still show an explosion even with large diameters of the nozzle plate hole. Examples of substances with a large limiting diameter are nitroglycerine (24 mm), diethyl azodicarboxylate (20 mm), methyl nitrate (18 mm), trinitrotoluene (5 mm) and ammonium perchlorate (8 mm).

swell

  1. ↑ H. Koenen, KH Ide: in Explosivstoffe 4 (1956) 119 and 143.
  2. ↑ H. Koenen, KH Ide, KH Swart: Safety-related characteristics of explosive substances in explosives 9 (1961) 4 and 30.
  3. ^ KH Ide, E. Haeusler, KH Swart: in Explosivstoffe 9 (1961) 195.
  4. ↑ a b c d Berthold, W .; Löffler, U .: Lexicon of safety-related terms in chemistry, Verlag Chemie Weinheim 1981, ISBN 3-527-25894-9 .
  5. ↑ Berger, A .; Wehrstedt, KD: Azodicarboxylates: Explosive properties and DSC measurements in J. Loss Prev. Proc. Ind. 23 (2010) 734-739, doi : 10.1016 / j.jlp.2010.06.019 .

literature

  • Regulation (EC) No. 440/2008 of the Commission of 30 May 2008 laying down test methods in accordance with Regulation (EC) No. 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) , Test method A.14 Explosion hazard
  • UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, Fifth Revisited Edition 2009, United Nations Publication, New York and Geneva, ISBN 92-1-139087-7
  • DIN EN-13631-2 Explosives for civil purposes - High explosives - Part 2: Determination of the thermal stability of explosives, Beuth Verlag
  • Koehler, J .; Meyer, R .; Homburg, A. Explosivstoffe, Tenth completely revised edition, Wiley-VCH Verlag GmbH & Co KGaA, Weinheim 2008, ISBN 978-3-527-32009-7
  • Thomas M. Klapötke : Chemistry of High-Energy Materials , 3rd Edition, 2015 Walter de Gruyter GmbH, Berlin / Boston, pp. 149–153, ISBN 978-3-11-043932-8 , e-ISBN (PDF) 978- 3-11-043933-5, e-ISBN (EPUB) 978-3-11-043047-9, (accessed from De Gruyter Online).