Since you actually have it inside an actual PCIe slot and inside an actual computer case, then chances are very rare of it catching fire.
Fire usually happens when people have like a 6 GPU mining rig with risers melting and mounted on a wood rig.
Is there some temp limit that it needs to get up over to catch fire? If I am under 100 C should it be ok? I have Afterburner so I am thinking maybe I should make a special profile that only allows it to go up to a certain temperature? You can also specify power there so maybe you can put down the power a bit to mine safely at a little lower intensity? Maybe you could also set fans to max? Or is there something negative with fans on max apart from higher noise?
So far I have not seen my temp in afterburner go over 75 when mining.
"If I am under 100 C should it be ok?"
NO NO NO NO NO NO NO.
Once you get close to 90C you're going to start melting shit. My cards are all running at or below 60C, that's colder than most, but I never let it exceed 70C.
That is right. I keep most of the cards between 60 to 70 degree.