Menu
Home Explore People Places Arts History Plants & Animals Science Life & Culture Technology
On this page
Autoignition temperature
Lowest temperature at which a substance spontaneously combusts

The autoignition temperature is the lowest temperature at which a substance spontaneously ignites without an external ignition source like a flame or spark, providing the necessary activation energy for combustion. This temperature varies with pressure, typically decreasing as pressure decreases. Substances that ignite spontaneously at ambient temperatures are called pyrophoric. Autoignition temperatures of liquids are commonly measured using a 500-millilitre flask in a temperature-controlled oven following ASTM E659 procedures. For plastics, testing may involve elevated pressure and pure oxygen, with ASTM G72 as the standard for assessing suitability in high-oxygen environments.

We don't have any images related to Autoignition temperature yet.
We don't have any YouTube videos related to Autoignition temperature yet.
We don't have any PDF documents related to Autoignition temperature yet.
We don't have any Books related to Autoignition temperature yet.
We don't have any archived web articles related to Autoignition temperature yet.

Autoignition time equation

The time t ig {\displaystyle t_{\text{ig}}} it takes for a material to reach its autoignition temperature T ig {\displaystyle T_{\text{ig}}} when exposed to a heat flux q ″ {\displaystyle q''} is given by the following equation:5

t ig = π 4 k ρ c [ T ig − T 0 q ″ ] 2 , {\displaystyle t_{\text{ig}}={\frac {\pi }{4}}k\rho c\left[{\frac {T_{\text{ig}}-T_{0}}{q''}}\right]^{2},}

where k = thermal conductivity, ρ = density, and c = specific heat capacity of the material of interest, T 0 {\displaystyle T_{0}} is the initial temperature of the material (or the temperature of the bulk material).

Autoignition temperature of selected substances

Temperatures vary widely in the literature and should only be used as estimates. Factors that may cause variation include partial pressure of oxygen, altitude, humidity, and amount of time required for ignition. Generally the autoignition temperature for hydrocarbon/air mixtures decreases with increasing molecular mass and increasing chain length. The autoignition temperature is also higher for branched-chain hydrocarbons than for straight-chain hydrocarbons.6

SubstanceAutoignition[D]Note
Barium550 °C (1,022 °F)550±907[C]
Bismuth735 °C (1,355 °F)735±208[C]
Butane405 °C (761 °F)9
Calcium790 °C (1,450 °F)790±1010[C]
Carbon disulfide90 °C (194 °F)11
Diesel or Jet A-1210 °C (410 °F)12
Diethyl ether160 °C (320 °F)13
Ethanol365 °C (689 °F)14
Gasoline (Petrol)247–280 °C (477–536 °F)15
Hydrogen535 °C (995 °F)
Iron1,315 °C (2,399 °F)1315±2016[C]
Lead850 °C (1,560 °F)850±517[C]
Leather / parchment200–212 °C (392–414 °F)1819
Magnesium635 °C (1,175 °F)635±520[B][C]
Magnesium473 °C (883 °F)21[B]
Methane537 °C (999 °F)
Molybdenum780 °C (1,440 °F)780±522[C]
Paper218–246 °C (424–475 °F)2324
Phosphorus (white)34 °C (93 °F)25[A][B]
Silane21 °C (70 °F)26 or below
Strontium1,075 °C (1,967 °F)1075±12027[C]
Tin940 °C (1,720 °F)940±2528[C]
Triethylborane−20 °C (−4 °F)29
A On contact with an organic substance, melts otherwise.
B There are two distinct results in the published literature. Both are separately listed in this table.
C At 1 atm. The ignition temperature depends on the air pressure.
D Under standard conditions for pressure.

See also

References

  1. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  2. Lin, Guanyou (29 March 2023). "Auto-Ignition Temperature: Understanding the Science behind Spontaneous Combustion". To Chemistry Journal. 10 (1): 1. https://www.purkh.com/articles/autoignition-temperature-understanding-the-science-behind-spontaneous-combustion-101934.html#:~:text=Pressure%20can%20influence%20the%20auto,aerospace%20or%20deep%2Dsea%20exploration ↩

  3. E659 – 78 (Reapproved 2000), "Standard Test Method for Autoignition Temperature of Liquid Chemicals", ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. ↩

  4. S. Grynko, "Material Properties Explained" (2012), ISBN 1-4700-7991-7, p. 46. /wiki/ISBN_(identifier) ↩

  5. Principles of Fire Behavior. ISBN 0-8273-7732-0. 1998. /wiki/ISBN_(identifier) ↩

  6. Zabetakis, M. G. (1965), Flammability characteristics of combustible gases and vapours, U.S. Department of Mines, Bulletin 627. ↩

  7. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  8. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  9. "Butane - Safety Properties". Wolfram|Alpha. http://www.wolframalpha.com/input/?i=butane ↩

  10. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  11. Fuels and Chemicals - Autoignition Temperatures, engineeringtoolbox.com http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html ↩

  12. Cafe, Tony. "PHYSICAL CONSTANTS FOR INVESTIGATORS". tcforensic.com.au. TC Forensic P/L. Retrieved 11 February 2015. http://www.tcforensic.com.au/docs/article10.html ↩

  13. "Diethyl Ether - Safety Properties". Wolfram|Alpha. http://www.wolframalpha.com/input/?i=diethyl+ether ↩

  14. Fuels and Chemicals - Autoignition Temperatures, engineeringtoolbox.com http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html ↩

  15. Fuels and Chemicals - Autoignition Temperatures, engineeringtoolbox.com http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html ↩

  16. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  17. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  18. Cafe, Tony. "PHYSICAL CONSTANTS FOR INVESTIGATORS". tcforensic.com.au. TC Forensic P/L. Retrieved 11 February 2015. http://www.tcforensic.com.au/docs/article10.html ↩

  19. "Flammability and flame retardancy of leather". leathermag.com. Leather International / Global Trade Media. Retrieved 11 February 2015. http://www.leathermag.com/features/featureflammability-and-flame-retardancy-of-leather/ ↩

  20. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  21. Fuels and Chemicals - Autoignition Temperatures, engineeringtoolbox.com http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html ↩

  22. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  23. Cafe, Tony. "PHYSICAL CONSTANTS FOR INVESTIGATORS". tcforensic.com.au. TC Forensic P/L. Retrieved 11 February 2015. http://www.tcforensic.com.au/docs/article10.html ↩

  24. Tony Cafe. "Physical Constants for Investigators". Journal of Australian Fire Investigators. (Reproduced from "Firepoint" magazine) http://www.tcforensic.com.au/docs/article10.html ↩

  25. Fuels and Chemicals - Autoignition Temperatures, engineeringtoolbox.com http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html ↩

  26. Fuels and Chemicals - Autoignition Temperatures, engineeringtoolbox.com http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html ↩

  27. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  28. Laurendeau, N. M.; Glassman, I. (1971-04-01). "Ignition Temperatures of Metals in Oxygen Atmospheres". Combustion Science and Technology. 3 (2): 77–82. doi:10.1080/00102207108952274. /wiki/Doi_(identifier) ↩

  29. Fuels and Chemicals - Autoignition Temperatures, engineeringtoolbox.com http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html ↩