SDC fire damage

[jedi078]

Fire based magic spells would be a good place to start when looking for fire damage.

But the fire isn't what the characters have to worry about. It's the smoke and the building collapsing on them (I'd say for every ten pounds of debris that falls on a PC they'd take 1d4 damage). The smoke will obscure visibility, and make it hard to breath (use the character PE stat to determine how long they can last before the smoke causes them to lose conscious). Of course magic can counter the effects of both smoke and fire.

[drewkitty ~..~]

Fire based magic spells would be a good place to start when looking for fire damage.

But the fire isn't what the characters have to worry about. It's the smoke and the building collapsing on them (I'd say for every ten pounds of debris that falls on a PC they'd take 1d4 damage). The smoke will obscure visibility, and make it hard to breath (use the character PE stat to determine how long they can last before the smoke causes them to lose conscious). Of course magic can counter the effects of both smoke and fire.

Fire based magic spells that give a damage per melee round would be a good place to start when looking for fire damage.

[Killer Cyborg]

I disagree that magic spells are the best option, though they may ultimately be all you have to go on.
Magic spells are magic; they're not the norm.

I'd look through old official adventures (PFRPG might be your best bet) and see if any of those list damage for that kind of thing.
There might actually be a situation close to what you're describing, somewhere in print.

Also, I'd check out the HU super powers section. Like magic, super powers are not the norm... but they're more indirect, and interact better with the norm.
The powers for controlling radiation and/or fire, iirc, describe powers that raise the temperature to high degrees, and that might simulate a burning building type scenario.
Maybe the Alter Physical Structure: Fire power as well.

[The Dark Elf]

IMO circle of flame & wall of flame the the closest choices. They state:

The heat and smoke from the wall causes 1D6 damage to anybody within four feet (1.2 m), attempting to run or leap through the flames causes 4D6 damage per five feet (1.5 m) of depth, plus there's a 1-60% chance that combustible items on the person will catch on fire, unless protected by magic or psionics.

[Grell]

Well in Dead Reign it states that damage from a flaming zombie is 3d6, so that might be a good place to go. You can up the damage based on what exactly is burning and the intensity of the fire. Exposure to the heat could be something like 1d6 per melee, but that's not based on anything I've ever read in the texts. I think Jedi's thoughts on smoke inhalation vs. PE is a good bet as well, though I recall reading about smoke inhalation somewhere before; maybe HU.