Fire Purge

An area enchanted with fire purge is protected against all types of normal and magical fires. Normal fires (including camp fires, torches, and oil fires) cannot burn in the area of effect. Magical fires (including fiery dragon breath, other creature-generated fires, and spell-related fires such as Burning Hands and Fireball) cause only 50% of their normal damage. Additionally, creatures within the area of effect receive a +4 bonus to saving throws made vs. fire attacks, regardless of whether the attacks originate inside or outside the warded area.
Fire purge has no effect on fires that are within the area of effect when the spell is cast, (i.e., it does not extinguish existing fires).
Fire purge can be cast as cooperative magic. If a number of priests cast this spell simultaneously, its effectiveness is significantly increased. The duration of the spell is then equal to 1 turn per level of the most powerful priest plus 1 turn for every other contributing priest. The area of effect is a square whose sides equal the number of priests times 10 yards (thus, six priests could create a 60-yard by 60-yard square of protection).

[Tome of Magic]

Sphere: Wards
(Abjuration)
Level: 4
Solo/Cooperative

Range: 10 yards/level
Components: V, S, M
Duration: 1 turn/level
Casting Time: 1 turn
Area of Effect: 10-yard square/priest
Saving Throw: None

Material Components:
the priest's holy symbol and a scorched sliver of wood