If you know you're gonna be taking lots of fire damage in the quest, you wear Firebreak instead of your normal, general purpose armor. Of course, it's still not enough to save you from an EH ballista in Storm the Beaches.
But for, say, a cleric doing the Fire Peak raid? Hard to find a better choice for keeping you from getting torn up by stray fire.
I stand by the Mournlode suggestion, however. Healer's Bounty triggers often enough to really matter, and it's a CL10 Heal spell. So ability damage, poison, disease, and ability drain debuffs all go poof when it does. (It's 2% chance, which is higher than a Lightning Strike weapon's chance to proc.) And at ML20, you can ER over and over and just keep coming back to it (or never stop using it in the first place). If you Tier3 it, it gets a blue slot too, but becomes BTC then.