Lighting/materials setup for mental ray...no special plugins required. Noise controllers simulate flickering. Material for the small floor section came from the 'maps' folder in the 'archmat' folder of the max installation directory.
Fully adjustable wind, gravity & drag space warps are set up for the smoke & sparks. This particular example required the smoke to ascend into the 'tube' vent; hence the drag warp. Easily modified for a wall-based fireplace if you have the geometry.
Rendered on a 64 bit system with uncompressed avi's (very large set of 10 files - 57 megs in a zipped file), so provided below is a smaller archive of QT *.mov's. The original clips are freely available (internet search for 'detonation film's free stuff). They turned out to be quite useful, and the clips are looped short segments of the originals.
For the animated preview, a playback rate of .8 was used (in the material editor). Adjust playback rate depending on the scale of the fire, and be sure 'loop' is checked....