Adding Onto The Box!

Hey, Ive got two gro projects going on. One fairley large gro in a room and one in a stealth box. im starting to get get concerned about the stealth box. I currentley have a 40 watt hps light running and 2 20 watt cfls. Im about to add another 80 wat cfl. Keep in mind this box is only about 22 inches tall and roughley 24 inches wide and about half that deep. Im acustomed to room grows with all the space I need. My concern is, at which point are there too many lights in the box. Considering how small it is, when does it become a relative fire hazard...

I think as long as you keep the lights away from any flamable material, and keep it cool in there you should be fine i guess. maybe put a smoke alarm in there too, just in case right?