In The Burning Crusade it is item level 115 and requires level 70. In Wrath of the Lich King it is item level 251 and requires level 80. In MoP Classic it is item level 115 and requires level 70.
Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Heart-Flame Leggings Compares
Who It Suits
Mail is the armor type Evoker, Hunter and Shaman wear. With Agility or Intellect, Heart-Flame Leggings suits Beast Mastery, Marksmanship and Survival Hunter; Elemental, Enhancement and Restoration Shaman; Devastation, Preservation and Augmentation Evoker.
Similar Items
The 10 items nearest to Heart-Flame Leggings (item level 32) in item level among Armor > Mail, Legs slot, from item level 29 to 35.
Blizzard numbers items as they are created, so the named items next to ID 28751 (28746 to 28756) were usually added in the same batch as Heart-Flame Leggings: the same quest line, zone, vendor or reward set.