International Building Code 3406.1
Conformance. No change shall be made in the use or
occupancy of any building that would place the building in a
different division of the same group of occupancy or in a different
group of occupancies, unless such building is made to comply
with the requirements of this code for such division or
group of occupancy. Subject to the approval of the building
official, the use or occupancy of existing buildings shall be permitted
to be changed and the building is allowed to be occupied
for purposes in other groups without conforming to all the
requirements of this code for those groups, provided the newor
proposed use is less hazardous, based on life and fire risk, than
the existing use.
International Building Code 3406.2
Certificate of occupancy. A certificate of occupancy
shall be issued where it has been determined that the requirements
for the new occupancy classification have been met.
International Building Code 3406.3
Stairways. Existing stairways in an existing structure
shall not be required to comply with the requirements of a new
stairway as outlined in Section 1009 where the existing space
and construction will not allow a reduction in pitch or slope.
International Building Code 3406.4
Change of occupancy. When a change of occupancy
results in a structure being reclassified to a higher occupancy
category, the structure shall conform to the seismic requirements
for a new structure.
Exceptions:
1. Specific seismic detailing requirements of this code
or ASCE 7 for a new structure shall not be required to
be met where it can be shown that the level of performance
and seismic safety is equivalent to that of a
new structure. Such analysis shall consider the regularity,
overstrength, redundancy and ductility of the
structure within the context of the existing and retrofit
(if any) detailing provided.
2. When a change of use results in a structure being
reclassified from Occupancy Category I or II to Occupancy
Category III and the structure is located in a
seismic map area where SDS < 0.33, compliance with
the seismic requirements of this code and ASCE 7 are
not required.