TNT equivalent

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"Kiloton" redirects here. For the similarly named weight measurements, see Tonne.
Diagram of explosive yield vs mushroom cloud height, illustrating the difference between 22 kiloton Fat Man and 15 megaton Castle Bravo explosions[citation needed]

TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The "ton of TNT" is a unit of energy defined by that convention to be 4.184 gigajoules,[1] which is the approximate energy released in the detonation of a metric ton (1,000 kilograms or one megagram) of TNT. The convention intends to compare the destructiveness of an event with that of conventional explosives, of which TNT is a typical example (although other conventional explosives such as dynamite contain more energy).

Kiloton and megaton[edit]

The "kiloton (of TNT)" is a unit of energy equal to 4.184 terajoules.

The "megaton (of TNT)" is a unit of energy equal to 4.184 petajoules.

The kiloton and megaton of TNT have traditionally been used to describe the energy output, and hence the destructive power, of a nuclear weapon. The TNT equivalent appears in various nuclear weapon control treaties, and has been used to characterize the energy released in such other highly destructive events as an asteroid impact.[2]

Historical derivation of the value[edit]

A gram of TNT releases 2673–6702 J (joules) upon explosion.[3] The energy liberated by one gram of TNT was arbitrarily defined as a matter of convention to be 4184 J,[4] which is exactly one kilocalorie.

An explosive's energy is normally expressed as the thermodynamic work produced by its detonation, which for TNT has been accurately measured as 4686 J/g from a large sample of air blast experiments, and theoretically calculated to be 4853 J/g.[5]

The measured, pure heat output of a gram of TNT is only 2724 J,[6][clarification needed] but this is not the important value for explosive blast effect calculations.

Alternative TNT equivalency can be calculated as a function of when in the detonation the value is measured and which property is being compared.[7][8][9][10]

A kiloton of TNT can be visualized as a cube of TNT 8.46 metres (27.8 ft) on a side.

Grams TNT Symbol Tons TNT Symbol Energy [Joules] Energy [Wh] Corresponding mass loss
gram of TNT g microton of TNT μt 4.184×103 J or 4.184 kilojoules 1.163 Wh 46.55 pg
kilogram of TNT kg milliton of TNT mt 4.184×106 J or 4.184 megajoules 1.163 kWh 46.55 ng
megagram of TNT Mg ton of TNT t 4.184×109 J or 4.184 gigajoules 1.163 MWh 46.55 μg
gigagram of TNT Gg kiloton of TNT kt 4.184×1012 J or 4.184 terajoules 1.163 GWh 46.55 mg
teragram of TNT Tg megaton of TNT Mt 4.184×1015 J or 4.184 petajoules 1.163 TWh 46.55 g
petagram of TNT Pg gigaton of TNT Gt 4.184×1018 J or 4.184 exajoules 1.163 PWh 46.55 kg

Conversion to other units[edit]

1 ton TNT equivalent is approximately:

Examples[edit]

Further information: Orders of magnitude (energy)
Megatons of TNT Energy [Wh] Description
1×10−9 1.162 kWh Under controlled conditions one kilogram of TNT can destroy (or even obliterate) a small vehicle.
1×10−8 11.62 kWh The approximate radiant heat energy released during 3-phase, 600 V, 100 kA arcing fault in a 0.5 m × 0.5 m × 0.5 m (20 in × 20 in × 20 in) compartment within a 1-second period.[11][further explanation needed]
1.2×10−8 13.94 kWh Amount of TNT used (12 kg) in cathedral Coptic church explosion in Cairo, Egypt on December 11, 2016 that left 25 dead [12]
1×10−6 – 44×10−6 1.16 MWh – 51.14 MWh Conventional bombs yield from less than one ton to FOAB's forty four tonnes. The yield of a Tomahawk cruise missile is equivalent to 500 kg of TNT, or approximately 0.55 tons.[13]
2.5×10−6 2.90 MWh An American television show, MythBusters, used 2.5 tons of ANFO to make "homemade" diamonds.
5×10−4 581 MWh A real 0.5-kilotonne-of-TNT (2.1 TJ) charge at Operation Sailor Hat. If the charge were a full sphere, it would be 1 kilotonne of TNT (4.2 TJ).
500 tons of TNT (6 by 12 m (20 by 40 ft)) awaiting detonation at Operation Sailor Hat.
1×10−3–2×10−3 1.16 GWh – 2.32 GWh Estimated yield of the Oppau explosion that killed more than 500 at a German fertilizer factory in 1921.
2.3×10−3 2.67 GWh Amount of solar energy falling on 4,000 m2 (1 acre) of land in a year is 9.5 TJ (2,650 MWh) (an average over the Earth's disk).
3×10−3 3.49 GWh The Halifax Explosion in 1917 was the accidental detonation of 3,000 tons of TNT.
8×10−3 9.3 GWh Minor Scale, a 1985 United States conventional explosion, using 4,744 tons of ANFO explosive to provide a scaled equivalent airblast of an eight kiloton (33.44 TJ) nuclear device,[14] is believed to be the largest planned detonation of conventional explosives in history.
1.5×10−2–2×10−2 17.4 GWh – 23.2 GWh The Little Boy atomic bomb dropped on Hiroshima on August 6, 1945, exploded with an energy of about 15 kilotons of TNT (63 TJ), and the Fat Man atomic bomb dropped on Nagasaki on August 9, 1945, exploded with an energy of about 20 kilotons of TNT (84 TJ). The modern nuclear weapons in the United States arsenal range in yield from 0.3 kt (1.3 TJ) to 1.2 Mt (5.0 PJ) equivalent, for the B83 strategic bomb.
1 1.16 TWh The energy contained in one megaton of TNT (4.2 PJ) is enough to power the average American household for 103,000 years.[15] The 30 Mt (130 PJ) estimated upper limit blast power of the Tunguska event could power the aforementioned home for just over 3,104,226 years. To put that in perspective, the energy of that blast could power the entire United States for 3.27 days.[16]
3 3.5 TWh The total energy of all explosives used in World War Two (including the Hiroshima and Nagasaki bombs) is estimated to have been three megatons of TNT.
8.6 10 TWh The energy released by an "average" tropical cyclone in one minute, primarily from water condensation. Winds constitute a quarter of a percent of that energy.[17]
21.5 25 TWh The complete conversion of 1 kg of matter into pure energy would yield the theoretical maximum (E = mc2) of 89.8 petajoules, which is equivalent to 21.5 megatons of TNT. No such method of total conversion as combining 500 grams of matter with 500 grams of antimatter has yet been achieved. In the event of proton–antiproton annihilation, approximately 50% of the released energy will escape in the form of neutrinos, which are almost undetectable.[18] Electron–positron annihilation events emit their energy entirely as gamma rays.
24 28 TWh Approximate total yield of the 1980 eruption of Mount St. Helens.
25, 50, 100 29 TWh, 58 TWh, 116 TWh During the Cold War, the United States developed hydrogen bombs with maximum theoretical yields of 25 megatons of TNT (100 PJ). The Soviet Union developed a prototype weapon, nicknamed the Tsar Bomba, which was tested at 50 Mt (210 PJ), but had a maximum theoretical yield of 100 Mt (420 PJ).[19] The effective destructive potential of such a weapon varies greatly, depending on such conditions as the altitude at which it is detonated, the characteristics of the target, the terrain, and the physical landscape upon which it is detonated.
26.3 30.6 TWh Megathrust earthquakes 2004 Indian Ocean earthquake released record ME surface rupture energy, or potential for damage at 26.3 megatons of TNT (110 PJ).
200 232 TWh The total energy released by the eruption of Mt. Krakatoa in Indonesia in 1883.
540 628 TWh The total energy produced worldwide by all nuclear testing and combat combined, from the 1940s till now is about 540 megatons.
7,000 1.16 PWh The total global nuclear arsenal is about 30,000 nuclear warheads with a destructive capacity of 7,000 megatons or 7 gigatons (7,000 million tons) of TNT.
62,500 73 PWh The total solar energy received by Earth per minute is 440 exajoules.
875,000 1,000 PWh Approximate yield of the last eruption of the Yellowstone supervolcano.
6,000,000 = 6×106 6,973 PWh The estimated energy at impact when the largest fragment of Comet Shoemaker–Levy 9 struck Jupiter is equivalent to six million megatons (six trillion tons) of TNT.
9.32×106 10,831 PWh The energy released in the 2011 Tōhoku earthquake and tsunami was over 200,000 times the surface energy and was calculated by the USGS at 3.9×1022 joules,[20] slightly less than the 2004 Indian Ocean quake. This is equivalent to 9,320 gigatons of TNT, or approximately 600 million times the energy of the Hiroshima bomb.
9.56×106 11,110 PWh Megathrust earthquakes record huge MW values, or total energy released. The 2004 Indian Ocean earthquake released 9,560 gigatons TNT equivalent.
1×108 116,222 PWh The approximate energy released when the Chicxulub impact caused the mass extinction sixty six million years ago was estimated to be equal to 100 teratons (i.e. 100 exagrams or approximately 220.462 quadrillion pounds) of TNT. That is roughly eight billion times stronger than each of the bombs that hit Hiroshima and Nagasaki and the most energetic event on the history of Earth for hundreds of millions of years, far more powerful than any volcanic eruption, earthquake or firestorm. Such an explosion annihilated everything within a thousand miles of the impact in a split second. Such energy is equivalent to that needed to power the whole Earth for several centuries.
5.972×1015 6.94 x 1027 Wh The explosive energy of a quantity of TNT the mass of Earth.
7.89×1015 9.17 × 1027 Wh Total solar output in all directions per day.
1.98×1021 2.3 × 1033 Wh The explosive energy of a quantity of TNT the mass of the Sun.
2.4×1028–4.8×1028 2.8 × 1040 Wh – 5.6 × 1040 Wh On a much grander scale, a type 1a supernova explosion gives off 1–2×1044 joules of energy, which is about 2.4 to 4.8 hundred billion yottatons (24 to 48 octillion (2.4–4.8×1028) megatons) of TNT, equivalent to the explosive force of a quantity of TNT over a trillion (1012) times the mass of the planet Earth. The Type 1a supernova is essentially the fusion detonation of all the fusable fuel in a star of about 1.4 solar masses within a few seconds, and is a standard candle used for intergalactic distance measurements.
2.4×1030–4.8×1030 2.8 × 1042 Wh – 5.6 × 1042 Wh The largest supernova explosions witnessed, so-called gamma-ray bursts (GRBs) released more than 1046 joules of energy.[21]
1.3×1038 1.5 × 1050 Wh A merger of two black holes, first observation of gravitational waves, released 5.3×1047 joules

See also[edit]

References[edit]

  1. ^ "Tons (Explosives) to Gigajoules Conversion Calculator". unitconversion.org. 
  2. ^ "Joules to Megatons Conversion Calculator". unitconversion.org. 
  3. ^ Blast effects of external explosions (Section 4.8. Limitations of the TNT equivalent method) Archived August 10, 2016, at the Wayback Machine.
  4. ^ "Appendix B8 – Factors for Units Listed Alphabetically".  In NIST SI Guide 2008
  5. ^ Cooper, Paul W. (1996). Explosives Engineering. New York: Wiley-VCH. p. 406. ISBN 0-471-18636-8. 
  6. ^ Muller, Richard A. (2001–2002). "Chapter 1. Energy, Power, and Explosions". Physics for Future Presidents, a textbook. ISBN 978-1-4266-2459-9. [dead link]
  7. ^ Sorin Bastea, Laurence E. Fried, Kurt R. Glaesemann, W. Michael Howard, P. Clark Souers, Peter A. Vitello, Cheetah 5.0 User's Manual, Lawrence Livermore National Laboratory, 2007.
  8. ^ Maienschein, Jon L. (2002). Estimating equivalency of explosives through a thermochemical approach (PDF) (Technical report). Lawrence Livermore National Laboratory. UCRL-JC-147683. 
  9. ^ Maienschein, Jon L. (2002). Tnt equivalency of different explosives – estimation for calculating load limits in heaf firing tanks (Technical report). Lawrence Livermore National Laboratory. EMPE-02-22. 
  10. ^ Cunningham, Bruce J. (2001). C-4/tnt equivalency (Technical report). Lawrence Livermore National Laboratory. EMPE-01-81. 
  11. ^ "Arc blast Tri-Nitro-Toluene TNT Trotyl equivalent - ARCAD INC.". arcblasts.com. 
  12. ^ "Local media: Blast at Cairo cathedral kills at least 25". CNN. Retrieved 11 December 2016. 
  13. ^ "The Ingenuity Gap: Facing the Economic, Environmental, and Other Challenges", Thomas F. Homer-Dixon, p. 249.
  14. ^ TECH REPS INC ALBUQUERQUE NM (1986). "Minor Scale Event, Test Execution Report" (PDF). 
  15. ^ "Frequently Asked Questions – Electricity". United States Department of Energy. 2009-10-06. Retrieved 2009-10-21.  (Calculated from 2007 value of 936 kWh monthly usage)
  16. ^ "Country Comparison :: Electricity – consumption". The World Factbook. CIA. Retrieved 2009-10-22.  (Calculated from 2007 value of 3,892,000,000,000 kWh annual usage)
  17. ^ "NOAA FAQ: How much energy does a hurricane release?". National Oceanic & Atmospheric Administration. August 2001. Retrieved 2009-06-30.  cites 6e14 watts continuous.
  18. ^ Borowski, Stanley K. (March 1996). Comparison of Fusion/Antiproton Propulsion systems (PDF). 23rd Joint Propulsion Conference. NASA Glenn Research Center. doi:10.2514/6.1987-1814. hdl:2060/19960020441. 
  19. ^ See Currently deployed U.S. nuclear weapon yields Archived September 7, 2016, at the Wayback Machine., Complete List of All U.S. Nuclear Weapons Archived December 16, 2008, at the Wayback Machine., Tsar Bomba Archived June 17, 2016, at the Wayback Machine., all from Carey Sublette's Nuclear Weapon Archive.
  20. ^ "USGS.gov: USGS WPhase Moment Solution". Earthquake.usgs.gov. Archived from the original on 13 March 2011. Retrieved 13 March 2011. 
  21. ^ Maselli, A.; Melandri, A.; Nava, L.; Mundell, C. G.; Kawai, N.; Campana, S.; Covino, S.; Cummings, J. R.; Cusumano, G.; Evans, P. A.; Ghirlanda, G.; Ghisellini, G.; Guidorzi, C.; Kobayashi, S.; Kuin, P.; LaParola, V.; Mangano, V.; Oates, S.; Sakamoto, T.; Serino, M.; Virgili, F.; Zhang, B.- B.; Barthelmy, S.; Beardmore, A.; Bernardini, M. G.; Bersier, D.; Burrows, D.; Calderone, G.; Capalbi, M.; Chiang, J. (2013). "GRB 130427A: A Nearby Ordinary Monster". Science. 343 (6166): 48–51. doi:10.1126/science.1242279. PMID 24263134. 
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