Gas explosion

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Consequences of a gas explosion in an apartment building in Douai , France

A gas explosion is the special case of an explosion in which an explosive gas mixture ignites and burns down in a very short time. Depending on the amount, pressure and temperature of the gas, it can be a deflagration or detonation .

conditions

In order to be able to cause a gas explosion, both an explosive gas atmosphere and an ignition source are required. The explosive atmosphere consists of a flammable gas and oxygen , whereby the oxygen can be present as an air mixture. Ignitability is given if the concentration of the gas is between the upper and lower explosion limit . Various electrical or mechanical effects that provide the required ignition energy or ignition temperature can serve as ignition sources . With relatively high concentration ratios of certain gases (e.g. hydrogen ) or with turbulence (see e.g. the Buncefield tank farm fire), self-ignition can also occur without the need for an ignition source.

prevention

The measures that are necessary to prevent a gas explosion are dealt with in the area of gas explosion protection . Methods that can minimize the risk are presented here . Precautionary measures include preventing both an explosive atmosphere and the effects of an explosion. For this purpose, the legislature sets certain requirements for operators of systems with potentially explosive areas and for manufacturers of explosion-protected products. To meet the requirements, there are national and international standards that can be used by operators and manufacturers. In Germany, an inspection of natural gas systems is required every twelve years, and of liquid gas systems every 10 years. The German Gas and Water Association e. V. recommends an annual test that can be carried out by the owner himself. In the case of liquefied gas systems, the Federation of Energy Consumers recommends annual maintenance by an expert.

In order to warn of leaking natural gas , the gas network operators odorize the gas and add an odorous substance to warn residents in good time.

Fire fighting

If an ignitable gas mixture is present, one spark (for example, tear-off sparks from light switches , colliding metal, flashlight, etc.) is enough to ignite it. Gas explosions can cause property damage and personal injury. The rescue services of the fire brigade or other institutions can only intervene when the danger of the explosion has been minimized to an acceptable risk . This can be done, for example, by the operator of the gas network turning off the gas supply to the accident site until the mixture has evaporated or the gas burns off in a controlled manner at the gas outlet point. In the case of leaked containers of liquids or gases, sealing or the suction of escaping vapors can also be a suitable measure.

See also

Individual evidence

  1. ↑ Security in the house - the annual check. German Gas and Water Association e. V. (DVGW) - Technical-Scientific Association, accessed on August 3, 2020 .
  2. ↑ Maintenance of liquid gas tanks. Federation of Energy Consumers e. V., accessed on August 3, 2020 .
  3. ↑ Odorisation of natural gas. German Gas and Water Association e. V. (DVGW) - Technical-Scientific Association, accessed on August 3, 2020 .

literature

  • S. Bussenius: Scientific principles of fire and explosion protection. Kohlhammer, Stuttgart, Berlin, Cologne 1996, ISBN 3-17-013867-7
  • H. Groh: Explosion Protection. Elsevier Butterworth-Heinemann, Oxford, Expert-Verlag, Renningen 2004, ISBN 0-7506-4777-9
  • M. Hattwig and H. Steen: Handbook of Explosion Prevention and Protection. Wiley-VCH, Weinheim 2004, ISBN 3-527-30718-4