redox reactions involve large amounts of energy being converted. These reactions can be made to happen at a very high rate. Two options for this would be to increase contact area between reductant and oxidizer, usually environmental oxygen, by grinding the reductant into a fine powder or you increase the temperature, as a rule of thumb, an increase in 10K (=10°C) is said to increase the reaction time by a factor of two. A good way to increase temperature is to confine gases inside a solid container, like a metal pipe, since a gas' temperature is inversely proportional to its volume.

I am out of the loop. What would be the reason for doing this?