14B-5-508  Mixed use and occupancy.
The provisions of Section 508 of IBC are adopted by reference with the following modifications:
1.   Delete exception 1 to Section 508.1.
1.1.   Revise exception 2 to Section 508.1 by replacing "Table 415.6.2" with "the Chicago Fire Prevention Code."
2.   Revise Section 508.2.2 to read:
508.2.2 Allowable building height.
The allowable building height and number of stories above grade plane of the building containing accessory occupancies shall be in accordance with Section 504 for the main occupancy of the building.”
3.   Revise Section 508.2.3 to read:
508.2.3 Allowable building area.
The allowable area of the building shall be based on the applicable provisions of Section 506 for the main occupancy of the building. Aggregate accessory occupancies shall not occupy more than 25 percent of the floor area of the story nor more than 5 percent of the total floor area of the main occupancy in which they are located and shall not exceed the tabular area values for nonsprinklered buildings in Table 506.2 for each such accessory occupancy.
Exception: The building official and fire code official may jointly approve accessory occupancies exceeding the 5 percent and 25 percent limits when in their opinion such accessory occupancies do not unduly increase the hazard.”
4.   Revise the exceptions to Section 508.2.4 to read:
Exceptions:
1.   Group H occupancies shall not be classified as accessory occupancies and shall be separated from all other occupancies in accordance with Section 508.4.
2.   Group I-1, R-1, R-2, R-3, R-4 and R-5 dwelling units and sleeping units shall not be classified as accessory occupancies and shall be separated from other dwelling or sleeping units and from other occupancies contiguous to them in accordance with the requirements of Section 420.
3.   Motor-vehicle-related occupancies shall not be classified as accessory occupancies and shall be separated from other occupancies in accordance with Section 406.”
5.   Revise Section 508.3.2 to read:
508.3.2 Allowable building area, height and number of stories above grade plane.
The allowable building area, building height and number of stories above grade plane of the building or portion thereof shall be based on the most restrictive allowances for the occupancy groups under consideration for the type of construction of the building in accordance with Section 503.1.”
6.   Revise the exceptions to Section 508.3.3 to read:
Exceptions:
1.   Group H occupancies shall be separated from all other occupancies in accordance with Section 508.4.
2.   Group I-1, R-1, R-2, R-3, R-4 and R-5 dwelling units and sleeping units shall be separated from other dwelling or sleeping units and from other occupancies contiguous to them in accordance with the requirements of Section 420.
3.   Group A occupancies with an aggregate occupant load of 300 or more persons shall be separated from other main occupancies by construction providing a fire-resistance rating of not less than 2 hours.
4.   Group A occupancies with an aggregate occupant load of less than 300 persons shall be separated from other main occupancies by construction providing a fire-resistance rating of not less than 1 hour in buildings that are not protected throughout by an automatic sprinkler system in accordance with Section 903.3.1.1.
5.   Motor-vehicle-related occupancies shall be separated from other occupancies in accordance with Section 406.”
7.   Replace Table 508.4 as shown:
TABLE 508.4
REQUIRED SEPARATION OF OCCUPANCIES (HOURS)f
OCCUPANCY
A, E
I-1 a,
I-3, I-4
I-2
R a
F-2,
S-2 b, U
B e, M
F-1, S-1
H-1
H-2
H-3, H-4
H-5
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
OCCUPANCY
A, E
I-1 a,
I-3, I-4
I-2
R a
F-2,
S-2 b, U
B e, M
F-1, S-1
H-1
H-2
H-3, H-4
H-5
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
S
NS
A, E
Nh
Ng, h
2
3
3
NP
1h
2
1h
2
1h
2
1h
2
NP
NP
4
NP
4
NP
4
NP
I-1 a, I-3, I-4
N
N
2
NP
2
NP
3
4
3
4
3
4
NP
NP
4
NP
4
NP
4
NP
I-2
N
N
2
NP
3
NP
2
NP
2
NP
NP
NP
4
NP
4
NP
4
NP
R a
N
N
1
2
1
2
1
2
NP
NP
4
NP
4
NP
4
NP
F-2, S-2 b, U
N
N
1
2
1
2
NP
NP
3
4
4
4
4
NP
B e, M
N
N
1
2
NP
NP
3
4
4
4
3
NP
F-1, S-1
N
N
NP
NP
3
4
4
4
3
NP
H-1
N
NP
NP
NP
NP
NP
NP
NP
H-2
N
NP
2
NP
1
NP
H-3, H-4
2 d
NP
1
NP
H-5
N
NP
 
S   =   Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1.
NS   =   Buildings not equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1.
N   =   No separation requirement.
NP   =   Not Permitted.
a.   See Section 420.
b.   The required separation from parking garages and other motor-vehicle-related occupancies shall be in accordance with Section 406.
c.   [Reserved.]
d.   Separation is not required between occupancies of the same classification.
e.   See Section 422.2 for ambulatory care facilities.
f.   Occupancy separations that serve to define fire area limits established in Chapter 9 for requiring fire protection systems shall also comply with Section 707.3.10 and Table 707.3.10 in accordance with Section 901.7.
g.   Group A occupancies with an aggregate occupant load of less than 300 persons shall be separated from other occupancies by construction providing a fire-resistance rating of not less than one 1 hour in buildings that are not protected throughout by an automatic sprinkler system in accordance with Section 903.3.1.1.
h.   Group A occupancies with an aggregate occupant load of 300 or more persons shall be separated from other occupancies by construction providing a fire-resistance rating of not less than 2 hours.
8.   Revise Section 508.4.3, including the exception, to read:
508.4.3 Allowable building height and number of stories above grade plane.
Each separated occupancy shall comply with the building height limitations and story above grade plane limitations based on the type of construction of the building in accordance with Section 503.1.”
(Amend Coun. J. 2-19-20, p. 14473, Art. II, § 18; Amend Coun. J. 10-7-20, p. 21791, Art. II, § 8; Amend Coun. J. 6-25-21, p. 32180, Art. II, § 7)