Fire Protection vs Protection

Solution 1:

If you have a full set of Fire Protect IV Armor what will give you an Enchantment Protection Factor factor of 25 (9 EPF per-piece * 4, capped at 25). This should block 100% of the fire damage you may receive. Since the EPF is capped at 25, having 4 pieces is essentially a waste. It only takes three pieces of armor with Fire Protect IV to cap your EPF against fire. So you should put something else on that fourth piece of armor.

If you have a full set of Protect IV, that means your EPF will be 20 (5 EPF per piece). This will cut the damage you take by 80%.

See: http://www.minecraftwiki.net/wiki/Armor#Enchantments