The spell creates a zone 6 yards in diameter around the caster. Any fire within or brought into the zone - normal or magical fire, including fire balls fired into or out of the zone - will immediately go out. Lava and molten metal will solidify, although they will still be very hot.
Whilst maintaining a zone, a character may not cast any other spells or use the Meditation skill to recover magic points. If two or more zones touch or overlap, then both zones are instantaneously destroyed.