There is no distinction between ingress and egress stairs. If stairs are used for ingress (i.e., entry), then they are used for egress, too, and shall be designed as such. People have a tendency to egress via the pathway they used to get to where they are, especially if they are unfamiliar with the building.
Chapter 11, Section 1102.1, requires buildings to comply with the code and ANSI/ICC A117.1. ANSI/ICC A117.1 requires stairs to comply with Section 504. Landings at stairs shall provide the applicable maneuvering clearances at doorways per ANSI/ICC A117.1 Section 404.2.3. Virtually all of this is duplicated in the 2010 ADA Standards.