Sensitivity to impact

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The impact sensitivity describes the behavior of a substance (mostly an explosive ) towards mechanical stress. The criterion here is that the material decomposes explosively under the action of a defined impact energy with an audible bang.

Test method

The BAM drop hammer test developed by the Federal Institute for Materials Research and Testing (BAM) is used as the test method. By dropping a weight from a certain height onto a test body, this enables testing with a defined impact energy. This is the product of the height of fall and weight and is specified in the unit Joule (J).

Classifications

In terms of the Explosives Act and Regulation (EC) No. 440/2008 of the European Commission, a limit value of 40 joules applies , below which it is classified as an explosive substance . In addition to the test for friction sensitivity and the steel sleeve test , the drop hammer test is one of the tests required by the Explosives Act. The test is described as Test 3 (a) (ii) within the test series 3 part of the testing schemes for classifying explosives of Class 1 in the sense of dangerous goods regulations . The result is rated as positive here if an explosion is observed at least once in six tests with an impact energy of two joules or less.

Examples

Substances with high impact sensitivity (impact energy <0.5 J) such as nitroglycerine or nitrogen trichloride must be well protected from vibrations and impacts, as they otherwise detonate very easily . Further examples of explosives (sorted by decreasing impact sensitivity) are silver azide (impact energy 1 J), PETN (3 J), picric acid (7.5 J), trinitrotoluene (15 J), ammonium perchlorate (25 J) and TATB (50 J).

Other test methods

The dangerous goods regulations describe additional test methods for checking impact sensitivity that have been developed in other countries. These are the following:

  • Exam 3 (a) (i) Bureau of Explosives Fallhammer (USA)
  • Exam 3 (a) (iii) Rotter Exam (Great Britain)
  • Test 3 (a) (iv) 30 kg drop hammer test (France)
  • Test 3 (a) (v) Modified Type 12 Impact Apparatus (Canada)
  • Test 3 (a) (vi) Impact Sensitivity Test (Russia)

The dangerous goods regulations recommend the BAM drop hammer test as the preferred test method for testing explosives.

Individual evidence

  1. ↑ a b Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria. 5th, revised edition. ST / SG / AC.10 / 11 / Rev.5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM, pp. 80–87, (pdf)
  2. ↑ a b c d W. Berthold, U. Löffler: Lexicon of safety-related terms in chemistry. Verlag Chemie, Weinheim 1981, ISBN 3-527-25894-9 .
  3. ↑ J. Köhler, R. Meyer, A. Homburg: Explosivstoffe. 10th, completely revised edition. Wiley-VCH, Weinheim 2008, ISBN 978-3-527-32009-7 .
  4. ↑ Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria. 5th, revised edition. ST / SG / AC.10 / 11 / Rev. 5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM, pp. 74–79, (pdf)
  5. ↑ Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria. 5th, revised edition. ST / SG / AC.10 / 11 / Rev.5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM, pp. 88–95, (pdf)
  6. ↑ Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria. 5th, revised edition. ST / SG / AC.10 / 11 / Rev.5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM, pp. 96–99, (pdf)
  7. ↑ Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria. 5th, revised edition. ST / SG / AC.10 / 11 / Rev.5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM, pp. 100-103, (pdf)
  8. ↑ Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria. 5th, revised edition. ST / SG / AC.10 / 11 / Rev.5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM, pp. 104–110, (pdf)

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-13631-4 Explosives for civil purposes - High explosives - Determination of the impact sensitivity of explosives, Beuth Verlag.
  • J. Köhler, R. Meyer, A. Homburg: Explosivstoffe. 10th, completely revised edition. Wiley-VCH Verlag, Weinheim 2008, ISBN 978-3-527-32009-7 .
  • Thomas M. Klapötke : Chemistry of High-Energy Materials. 3. Edition. Walter de Gruyter, Berlin / Boston 2015, ISBN 978-3-11-043932-8 , pp. 149–153.