From WoWWiki

Dragonspire Hall is an area of Upper Blackrock Spire. It is accessed through the sealed door in the Hall of Blackhand, but one must be in the possession of the Seal of Ascension to open it. The hall is the first area where a 10-man group is recommended if the group is level 60. To access the next area, the Hall of Binding where Pyroguard Emberseer is located, one must defeat every single orc in this area.

Subzones of Blackrock Spire
Blackrock Stadium • Chamber of Battle • Dragonspire Hall • The Furnace • Hall of Binding • Hall of Blackhand • Halycon's Lair • Hordemar City • Mok'Doom • The Rookery • Skitterweb Tunnels • Spire Throne • The Storehouse • Tazz'Alaor