Ignition energy

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The energy given off by an ignition source is referred to as ignition energy. It is a variable that characterizes the ignition source. The ignition energy is an activation energy . The SI unit for the ignition energy is the joule .

With certain gas-air or dust-air mixtures, the ignition energy can have a very great influence on the explosion indicators. The explosion range can also be increased significantly through very high ignition energies in the kilojoule range . For example, with an ignition energy of 1 joule, the lower explosion limit (LEL) of a methane- air mixture is 4.9 vol.% And the upper explosion limit (UEL) 13.8%. With an ignition energy of 10 kilojoules, these limits shift to 3.6 vol.% (LEL) and 17.5 vol.% (OEG). Such high ignition energies are achieved, for example, by pyrotechnic detonators .

For the successful ignition or flammability of a substance it is important that a mass element of a flammable substance needs less ignition energy than it generates in the subsequent combustion of combustion heat . The resulting heat of combustion is required to ignite a neighboring element of the substance. The greater the ratio of combustion heat to ignition energy, the faster the combustion takes place. The extreme case is an explosion .

The minimum ignition energy is the lowest ignition energy that is just enough to ignite a flammable substance. It is an important parameter in safety technology.

literature

  • Wolfgang Bartknecht: Explosions: Procedure and protective measures. 2nd edition, Springer-Verlag, 2013, ISBN 3-6620-7157-6

Individual evidence

  1. ↑ a b Gisbert Rodewald: Fire theory. 6th edition, Verlag Kohlhammer, 2006, ISBN 3-1701-9129-2 , p. 182
  2. ↑ Peter Kurzweil: Chemistry: Basics, structural knowledge, applications and experiments. 10th edition, Springer-Verlag, 2015, ISBN 3-6580-8660-2 , p. 128
  3. ↑ Bartknecht p. 16 and 37
  4. ↑ Bartknecht p. 5
  5. ↑ Bartknecht p. 43
  6. ↑ Klaus Scheuermann: Praxishandbuch Fire Protection ( Memento of the original from February 26, 2017 in the Internet Archive ) Info: The @1@ 2Template: Webachiv / IABot / www.arbeitssicherheit.de archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Carl Heymanns Verlag, 2008
  7. ↑ Henrikus Stein (Ed.): Handbuch des Explosionsschutz John Wiley & Sons, 2012, ISBN 3-5276-6086-0 , p. 63