A thermal lance, thermic lance, oxygen lance, or burning bar is a tool that burns iron in the presence of pressurized oxygen to create very high temperatures for cutting. It consists of a long iron tube packed with iron rods, sometimes mixed with aluminium or magnesium rods to increase the heat output. One end of the tube is placed in a holder and oxygen is fed through the tube.
The far end of the tube is pre-heated and lit by an oxyacetylene torch. An intense stream of burning iron is produced at the lit end and can be used to cut rapidly through thick materials including steel and concrete. The tube is consumed, so every few minutes the operator shuts off the oxygen, discards the remaining stub of a lance tube and starts using a new one.
The temperature at which a thermal lance burns varies depending the environment.[1] Kosanke gives the maximum temperature to be 4,770 K (8,130 °F),[2] while Haorong calculates it to be 3,000 K (4,940 °F).[3]
Popular depictions of thermal lances sometimes exaggerate their capabilities. In the movie The Score Nick Wells (played by Robert De Niro) uses a thermal lance to cut a hole in the top of a safe, to avoid the safe's glass relocker device.
MythBusters[4] tested the capabilities of the thermal lance and discovered opening a modern safe with a thermal lance takes far longer than depicted in popular accounts. The intense heat also destroyed the items inside the vault. The MythBusters concluded that using a thermal lance for safe-cracking is plausible, but impractical.
There are examples in science fiction of "thermic lance" or "thermal lance" being used to mean a type of fictional energy weapon or melee weapon (for example at this link, with image, in the Fallout: New Vegas videogame scenario).