Depending on the particular situation - occupancy class, size, occupant load - there are some exceptions to the accessible route requirement.
1103.2.1 Specific requirements.
Accessibility is not required in buildings and facilities, or portions thereof, to the extent permitted by Sections 1104 through 1110.
1104.4 Multilevel buildings and facilities.
At least one accessible route shall connect each accessible level, including mezzanines, in multilevel buildings and facilities.
Exceptions:
1. An accessible route is not required to stories and mezzanines that have an aggregate area of not more than 3,000 square feet (278.7 m2) and are located above and below accessible levels. This exception shall not apply to:1.1. Multiple tenant facilities of Group M occupancies containing five or more tenant spaces;1.2. Levels containing offices of health care providers (Group B or I); or1.3. Passenger transportation facilities and airports (Group A-3 or B).2. Levels that do not contain accessible elements or other spaces as determined by Section 1107 or 1108 are not required to be served by an accessible route from an accessible level.
For accessible means of egress, we must look to chapter 10...
SECTION 1007 ACCESSIBLE MEANS OF EGRESS
1007.1 Accessible means of egress required.
Accessible means of egress shall comply with this section. Accessible spaces shall be provided with not less than one accessible means of egress. Where more than one means of egress are required by Section 1015.1 or 1021.1 from any accessible space, each accessible portion of the space shall be served by not less than two accessible means of egress.
The Code is silent with regard to non-accessible spaces here, but the implication is that only accessible spaces need to be provided with accessible means of egress.