IEBC has a section on historic buildings section 508, then refers you to chapter 12
Definition
[A] HISTORIC BUILDING. Any building or structure that
is one or more of the following:
1. Listed, or certified as eligible for listing, by the State
Historic Preservation Officer or the Keeper of the
National Register of Historic Places, in the National
Register of Historic Places.
2. Designated as historic under an applicable state or local
law.
3. Certified as a contributing resource within a National
Register, state designated or locally designated historic
district.
1201.1 Scope. It is the intent of this chapter to provide means
for the preservation of historic buildings. Historical buildings
shall comply with the provisions of this chapter relating to
their repair, alteration, relocation and change of occupancy.
[BS] 1201.2 Report. A historic building undergoing repair,
alteration, or change of occupancy shall be investigated and
evaluated. If it is intended that the building meet the requirements
of this chapter, a written report shall be prepared and
filed with the code official by a registered design professional
when such a report is necessary in the opinion of the code
official. Such report shall be in accordance with Chapter 1
and shall identify each required safety feature that is in compliance
with this chapter and where compliance with other
chapters of these provisions would be damaging to the contributing
historic features. For buildings assigned to Seismic
Design Category D, E or F, a structural evaluation describing,
at a minimum, the vertical and horizontal elements of the lateral
force-resisting system and any strengths or weaknesses
therein shall be prepared. Additionally, the report shall
describe each feature that is not in compliance with these provisions
and shall demonstrate how the intent of these provisions
is complied with in providing an equivalent level of
safety.
