Blast radius of mechanical explosion

[MatNX]

Imagine a container with compressed air ruptures. Inside is a metric ton of air, just very dense. If it explodes, ignoring fragments of the container and the ground, how would i calculate the blast radius? Do I need the Volume of the container or the density? I thought it might just be the radius of a sphere of air with the same mass but "regular" atmoshperic desity. But I don´t know, which is why I´m asking it here.

 

[Nugatory]

You don’t start with the volume of air, you start with the energy released by the explosion. For back-of-the-envelope purposes this will be the same as the energy required to pump the air into the tank in the first place.

You’ll get an energy in joules, and google will quickly tell you that 4000 joules is about what you’d get from one gram of TNT, so you can convert your tank explosion into an equivalent TNT explosion. There’s plenty of online data about blast radii in those terms.

If you do the calculations right, you will conclude that highly compressed air is more dangerous than you might think. A typical military hand grenade is lethal out to about five meters and dangerous at ten times that distance... and a full scuba tank makes for quite a bit bigger of an explosion.

[Edit: and I should add that a metric ton of air is much much more than what goes into a scuba tank.]

 

[MatNX]

Ok, thanks! That was really helpful!