You can have an empty emitting no collision planes (the texture is not animated, the object, however, has animated scale).
The planes here are animated so they start small, get larger, and then shrink back down again before disappearing. they also randomly rotate to make the fire look more realistic.
Notice that the object ends itself one logic tick After the animation finishes playing. This is only the logic for the plane with the fire texture to make it scale and rotate. it is parented to an empty that always tracks to the camera and moves along the global Z axis.
The emitters add that empty, and the empty is added with the fire plane.
Here I played around with the animation for scaling the flame, and the speed at which it rises. I am also using multiple emitters and I have adjusted the opacity on the flames to make them more transparent. I also having it randomly adding lamps that last for one logic tick to create the flickering effect.
(textures not packed, flames will be pink.)
Original blend file
Blend file with campfire