TNT equivalent

TNT equivalent is a not SI-conformal, but further common unit for the energy freed with an explosion. The indication refers to the entire freed energy, not only to the kinetic energy, which can be clearly smaller for example with nuclear weapons than the total energy. Therefore the explosive yield is only conditionally comparable with the one appropriate quantity of the explosive TNT.

TNT equivalent used for the indication of the explosive yield of military weapons, industriellen explosives as well as other explosives, or also generally for the sudden release of energy, e.g. by meteorite impacts. Simplifying only the equivalent weight (“explosive yield 2 kilotons”) is sometimes called. Apart from the set free energy also the time is considered, which is necessary for the release.

TNT has a molecular mass of 227,1 g/mol and sets an energy of not completely for 250 kcal/mol freely (at present the definition not on joules (of J), but counted on thermochemical calories (cal)). From it a power density of approximately 1100 results kcal/kg or 4.6 MJ/kg. In order to have a “handy” unit, a calorie was taken as basis and the energy equivalent of a kiloton TNT was defined as 1 1012 cal and/or 4.184 1012 J: 106 cal/kg = 4.184 106 J/kg = 4.184 MJ/kg. Or briefly:1 kT (kiloton TNT) = 4,184*1012 J

Units are kilotons (kT), megatons (MT) and Gigatonnen (GT). In order to avoid confounding with masses, the TNT equivalent units with capital letters are written, thus MT instead of Mt.

The TNT equivalent of fire works is under a gram. Explosive devices, which are used in notices of terror, to have an explosive yield from 0,5 to 1000 kilograms TNT. A TNT equivalent of a kiloton, underground appliziertes in suitable depth, produces quake of the strength 4 on the judge scale at the earth’s surface about. The atom bomb, which was dropped the United States 1945 over Hiroshima, had an explosive yield of approximately 15 kilotons TNT. The sum all (of conventional) bombs, which were thrown in the Second World War on cities, achieves estimated 2 megatons. In the year 1961 by the USSR the largest ever tested hydrogen bomb with approx. 50 megatons TNT equivalent was ignited (Zar bomb).

Other explosives compared with TNT

Wood has the three-way power density of TNT. Nevertheless its “explosive yield” is small, there the achievement, D. i. the Energiefreisetzung per time, compared with typical explosives is very small. Korrekturfaktoren consider the explosiveness of different explosives. One receives the values by the comparison of the pressure waves or impulse waves, which produce the explosives compared with TNT. For wood a reference value close 0 would result.

Explosive yield of chemical explosives and explosive mixtures in relation to the explosive yield of TNT:

Black powder0,25 to 0,4
Nitrate of ammonia0,5

See also

  • Remaining LOCK bulge
  • Sand test