You can cause destructive fires with any spell.
Prerequisite: Ability to cast a spell with the fire descriptor
Benefit: You can use this feat to affect any spell that inflicts damage. Upon a failed save the target must make a Reflex save against the spell’s original Difficulty Class or catch on fire (dealing 1d6 fire damage per round until the target spends a standard action extinguishing the flames), in addition to the normal damage. Spells with this template gain the fire descriptor. If the spell already has the fire descriptor, the Reflex save is required even upon a successful save. A burning spell uses up a spell slot of the same level as the spell’s actual level.
Special: This feat cannot be applied to a spell without a saving throw or with the cold descriptor.