77 Ill. Adm. Code 330.3350
General Building Requirements
Section 330
Section 330.3350Â General
Building Requirements
a)Â Â Â Â Â Â Â Â Facilities of only one story in height shall be constructed of
fire resistive construction, protected noncombustible construction, protected
ordinary construction, protected wood frame construction, heavy timber
construction, or unprotected noncombustible construction. All facilities
except those of fire resistive construction or protected noncombustible
construction shall be equipped throughout with an automatic extinguishing
system. (A, B)
b)Â Â Â Â Â Â Â Â Facilities of more than one story in height shall be constructed
of fire resistive construction, except facilities of not more than three
stories in height may be constructed of protected noncombustible construction
if equipped throughout with an automatic extinguishing system. (A, B)
c)Â Â Â Â Â Â Â Â A story is that portion of a building between the upper
surface of any floor and the upper surface of the floor next above, except that
the topmost story shall be that portion of a building between the upper surface
of the topmost floor and the upper surface of the roof above.
d)Â Â Â Â Â Â Â Â A basement is any story or floor level below the main or
street floor. Where, due to grade differences, there are two levels each
qualifying as a street floor, a basement is any floor level below the lower of
the two street floors. Basements shall not be counted in determining the
height of a building in stories.