Normally, when I'm blasting fellow Pyros with my flamethrower, they take no less damage per second from my flames than non-Pyros (ignoring afterburn). However, I've noticed that, when I shoot a Detonator shot at a Pyro, instead of taking the standard 30 damage (and afterburn), he takes only 11 damage.

Does this mean that the Pyro has some fire resistance (I know that Pyros are immune to afterburn, but I'm asking about whether they take the standard amount of fire damage that other classes take), or is this just a property of the Detonator?