Spontaneous combustion

Spontaneous combustion

Spontaneous combustion is a type of combustion which occurs without an external ignition source.

How spontaneous combustion occurs

# A substance with a relatively low ignition temperature begins to release heat, which may occur in several ways, such as oxidation or fermentation.
# The heat is unable to escape, and the temperature of the material rises
# The temperature of the material rises above its ignition point
# Combustion begins, if sufficient oxygen is present.

Pyrophoric substances

The element sodium is an example of a pyrophoric material which can undergo a kind of spontaneous (and potentially very violent) explosion when exposed to oxygen, water, or moisture in the air. Pyrophoric substances have an autoignition temperature below room temperature and often require mere contact with air or water in order to spontaneously ignite. A characteristic of pyrophoric materials is also their large specific surface of contact with air. The Nickel of Raney is pyrophoric because of the very fine size of its particules.

Some materials which can spontaneously combust

*Haystacks and unprocessed cotton may self-ignite because of heat produced by bacterial fermentation. [cite web |url=http://www.wa-hay.org/publications/Spontaneous%20Combustion%20in%20Hay%20Stacks.pdf|title=Spontaneous Combustion in Hay Stacks|accessdate=2008-05-09 |format= |work= ]
*Grain dust in a hot metal silo can explode violently, destroying the structure.
*Boiled linseed oil in a partially confined space (such as a pile of oil-soaked rags left out in an uncovered container) can oxidize leading to a buildup of heat and thus ignition. [ [http://wildwoodsurvival.com/survival/fire/spontaneouscombustion/rbjul05/index.html Wildwood Survival - Fire - Reflectors ] ]
*Coal can spontaneously ignite when exposure to oxygen causes it to react and heat up when there is insufficient ventilation for cooling. [http://www.saftek.net/worksafe/bull94.txt]
* Pyrite oxidation is often the cause of coal spontaneous ignition in old mine tailing.
*Pistachio nuts are highly flammable when stored in large quantities, and are prone to self-heating and spontaneous combustion. [cite web |url=http://www.tis-gdv.de/tis_e/ware/nuesse/pistazie/pistazie.htm#selbsterhitzung |title=Pistachio Nuts |accessdate=2007-11-05 |format= |work= ]
*People have also been reported as spontaneously combusting. However the phenomenon is not considered true spontaneous combustion, as it is largely attributed to the wick effect, whereby an external source of fire ignites nearby flammable materials and human fat.

afety

In general practice, the threat of spontaneous combustion can be substantially reduced by placing the material in a tightly confined, self-closing disposal container (thus greatly limiting the supply of oxygen or water vapor), or submerging it in a fluid which smothers the reaction before it can begin. Depending on the hazard, this protective fluid may be water, kerosene (especially for a reactive metal such as sodium, which ignites upon contact with water) or an inert gas such as nitrogen or argon.

ee also

*Combustion.
*Backdraft: spontaneous ignition of hot gases produced by incomplete combustion of flamable materials in a poorly ventilated room (pyrolysis gases) when oxygen is suddently admitted into the system.
*Flashover: similar to backdraft but occurs without sudden ventilation.
*Spontaneous human combustion.

References

External links

* [http://www.saftek.net/worksafe/bull94.txt Article on the spontaneous combustion of coal]
* [http://www.wildwoodsurvival.com/survival/fire/spontaneouscombustion/rbjul05/index.html Spontaneous combustion demonstration]


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Spontaneous combustion — Spontaneous Spon*ta ne*ous (sp[o^]n*t[=a] n[ e]*[u^]s), a. [L. spontaneus, fr. sponte of free will, voluntarily.] 1. Proceeding from natural feeling, temperament, or disposition, or from a native internal proneness, readiness, or tendency,… …   The Collaborative International Dictionary of English

  • Spontaneous Combustion — bezeichnet: den Originaltitel des Filmes Fire Syndrome Spontaneous Combustion (1970er Jahre), eine Rockband der 1970er Jahre Spontaneous Combustion (US Band), eine US amerikanische Band, gegründet 1986 Diese Seite ist eine …   Deutsch Wikipedia

  • spontaneous combustion — n. the process of catching fire as a result of heat generated by internal chemical action …   English World dictionary

  • Spontaneous Combustion — Эпизод South Park Самопроизвольное возгорание Spontaneous Combustion Самовозгорание Кенни. Сезон: Сезон 3 Эпизод: 302 (#33) Сценарист: Трей Паркер Мэтт Стоун Дэвид Гудман Режиссёр …   Википедия

  • spontaneous combustion — the ignition of a substance or body from the rapid oxidation of its own constituents without heat from any external source. [1800 10] * * *       the outbreak of fire without application of heat from an external source. Spontaneous combustion may …   Universalium

  • spontaneous combustion — savaiminis užsidegimas statusas T sritis ekologija ir aplinkotyra apibrėžtis Medžiagos suliepsnojimas arba smilkimo pradžia dėl medžiagoje vykstančių egzoterminių procesų. atitikmenys: angl. spontaneous combustion; spontaneous ignition vok.… …   Ekologijos terminų aiškinamasis žodynas

  • spontaneous combustion — noun ignition of a substance (as oily rags) resulting from an internal oxidation process • Hypernyms: ↑ignition * * * noun [noncount] technical : burning that is caused by chemical actions inside of something rather than by heat from the outside… …   Useful english dictionary

  • Spontaneous combustion (disambiguation) — Spontaneous combustion may refer to:* Spontaneous combustion, the self ignition of a mass, for example, a pile of oily rags. * Spontaneous Combustion (album), a 2007 album by Liquid Trio Experiment * Spontaneous Combustion (film), a 1990 film by… …   Wikipedia

  • Spontaneous Combustion (band) — Spontaneous Combustion were an English progressive rock power trio active in the 1970s. The band consisted of Gary Margetts on guitar and lead vocals, his brother Tristiam Tris Margetts on bass guitar, and drummer Tony Brock. Spontaneous… …   Wikipedia

  • Spontaneous Combustion (film) — Infobox Film name = Spontaneous Combustion caption = writer = Howard Goldberg starring = Brad Dourif director = Tobe Hooper producer = Jim Rogers distributor = released = February 23, 1990 runtime = 97 min. country = USA language = English budget …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”