International Building Code 503.1
General. The height and area for buildings of different
construction types shall be governed by the intended use of the
building and shall not exceed the limits in Table 503 except as
modified hereafter. Each part of a building included within the
exterior walls or the exterior walls and fire walls where provided
shall be permitted to be a separate building.
International Building Code 503.1.1
Special industrial occupancies. Buildings and
structures designed to house special industrial processes
that require large areas and unusual heights to accommodate
craneways or special machinery and equipment, including,
among others, rolling mills; structural metal fabrication
shops and foundries; or the production and distribution of
electric, gas or steam power, shall be exempt from the height
and area limitations of Table 503.
International Building Code 503.1.2
Buildings on same lot. Two or more buildings on
the same lot shall be regulated as separate buildings or shall
be considered as portions of one building if the height of
each building and the aggregate area of buildings are within
the limitations of Table 503 as modified by Sections 504 and
506. The provisions of this code applicable to the aggregate
building shall be applicable to each building.
International Building Code 503.1.3
Type I construction. Buildings of Type I construction
permitted to be of unlimited tabular heights and areas
are not subject to the special requirements that allow unlimited
area buildings in Section 507 or unlimited height in
Sections 503.1.1 and 504.3 or increased height and areas for
other types of construction.