Originally Posted by quaoar
As for large fires in refineries you can see the firefighters use immense amount of water, but not to take out the fire, just to cool down the areas around the fire until someone can blow out the fire using explosives - you can find many videoes of this on the net.
Umm, I think you're confusing "refinery" with "drill head".
Drill heads are a pressurized delivery point source, so the idea is to use the explosion to blast the burning section of sprayed fuel away from the source such that it cools enough to not ignite as it comes out. Oxygen starvation probably plays a part as well.
Refineries will have large standing sources; not something you'd want to use explosives on (though, I suppose, a ruptured pipeline or broken valve or plug could be combatted in that manner.)