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Chapter 5 General Building Heights and Areas

CALIFORNIA BUILDING CODE — MATRIX ADOPTION TABLE
CHAPTER 5 — GENERAL BUILDING HEIGHTS AND AREAS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user.
See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC
-CG
 SFM HCD DSA OSHPD BSCC DPH AGR DWR CEC CA SL SLC
1 2 1/AC AC SS SS/CC 1 1R 2 3 4 5
Adopt entire chapter X             X X X X X X X X                
Adopt entire chapter as
amended (amended
sections listed below)		     X X X                                    
Adopt only those sections
that are listed below		                                              
Chapter / Section                                              
503.1, Exception 1     X X                                      
Figure 5-1     X                                        
Table 504.3     X                                        
Table 504.4     X                                        
Table 506.2     X                                        
506.2.3     X                                        
506.2.4     X                                        
508.2.4     X                                        
508.3.3     X                                        
Table 508.4     X                                        
508.5       X X                                    
508.5.3 Exception       X X                                    
508.5.8 Exception       X X                                    
508.5.9           X X                                
508.5.10       X X                                    
508.5.11           X                                  
Table 509.1       X                                      
509.3       X                                      
The state agency does not adopt sections identified with the following symbol: †
The Office of the State Fire Marshal's adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
User note:
About this chapter: Chapter 5 establishes the limits to which a building can be built. Building height, number of stories and building area are specified in this chapter. Chapter 5 must be used in conjunction with the occupancies established in Chapter 3 and the types of construction established in Chapter 6. This chapter also specifies the impact that mezzanines, accessory occupancies and mixed occupancies have on the overall size of a building.

Section 501 General

501.1 Scope

The provisions of this chapter control the height and area of structures hereafter erected and additions to existing structures.

Section 502 Building Address

[F] 502.1 Address Identification

New and existing buildings shall be provided with approved address identification. The address identification shall be legible and placed in a position that is visible from the street or road fronting the property. Address identification characters shall contrast with their background. Address numbers shall be Arabic numbers or alphabetical letters. Numbers shall not be spelled out. Each character shall be a minimum of 4 inches (102 mm) high with a minimum stroke width of 1/2 inch (12.7 mm). Where required by the fire code official, address identification shall be provided in additional approved locations to facilitate emergency response. Where access is by means of a private road and the building address cannot be viewed from the public way, a monument, pole or other approved sign or means shall be used to identify the structure. Address identification shall be maintained.
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Section 503 General Building Height and Area Limitations

503.1 General

Unless otherwise specifically modified in Chapter 4 and this chapter, building height, number of stories and building area shall not exceed the limits specified in Sections 504 and 506 based on the type of construction as determined by Section 602 and the occupancies as determined by Section 302 except as modified hereafter. Building height, number of stories and building area provisions shall be applied independently. For the purposes of determining area limitations, height limitations and type of construction, each portion of a building separated by one or more fire walls complying with Section 706 shall be considered to be a separate building.
Exceptions:
  1. [HCD 1] Limited-density owner-built rural dwellings may be of any type of construction which will provide for a sound structural condition. Structural hazards which result in an unsound condition and which may constitute a substandard building are delineated by Section 17920.3 of the Health and Safety Code.
  2. Other than structural requirements, solar photovoltaic panels supported by a structure with no use underneath shall not constitute additional story or additional floor area and may exceed the height limit when constructed on a roof top of a building provided the following conditions are met:
    1.1.  For all occupancies, the highest point of the structure/panel shall meet the lower of the two values below:
    1. 3' above the allowable building height per this code.
    2. 3' above the roof of the building immediately below.
    2.1.  For installations on flat roofs in other than Group R-3 and R-4 occupancies, the highest point of the structure/panel shall meet the lower of the two values below:
    1. 10' above the allowable building height per this code.
    2. 10' above the roof of the building immediately below.
  3. Other than structural requirements, solar photovoltaic panels supported by a structure over parking stalls shall not constitute additional story or additional floor area and may exceed the height limit as specified in exception 2 (above) when the following conditions are met (see Figure 5-1):
    1. The area within the perimeter of the photovoltaic array has maximum rectangular dimension of 40 feet by 150 feet.
    2. The distance between solar photovoltaic array structures is a minimum of 10 feet clear.
    3. The driveway aisle separating solar photovoltaic array structures has a minimum width of 25 feet clear.
    4. Solar photovoltaic array structure is used only for parking purposes with no storage.
    5. Completely open on all sides (other than necessary structural supports) with no interior partitions.
FIGURE 5-1
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503.1.1 Special Industrial Occupancies

Buildings and structures designed to house special industrial processes that require large areas and unusual building 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 building height, number of stories and building area limitations specified in Sections 504 and 506.

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 where the building height, number of stories of each building and the aggregate building area of the buildings are within the limitations specified in Sections 504 and 506. The provisions of this code applicable to the aggregate building shall be applicable to each building.
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503.1.3 Type I Construction

Buildings of Type I construction permitted to be of unlimited tabular building heights and areas are not subject to the special requirements that allow unlimited area buildings in Section 507 or unlimited building height in Sections 503.1.1 and 504.3 or increased building heights and areas for other types of construction.

503.1.4 Occupied Roofs

A roof level or portion thereof shall be permitted to be used as an occupied roof provided the occupancy of the roof is an occupancy that is permitted by Table 504.4 for the story immediately below the roof. The area of the occupied roofs shall not be included in the building area as regulated by Section 506. An occupied roof shall not be included in the building height or number of stories as regulated by Section 504, provided that the penthouses and other enclosed rooftop structures comply with Section 1511.
Exceptions:
  1. The occupancy located on an occupied roof shall not be limited to the occupancies allowed on the story immediately below the roof where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and occupant notification in accordance with Sections 907.5.2.1 and 907.5.2.3 is provided in the area of the occupied roof. Emergency voice/alarm communication system notification per Section 907.5.2.2 shall also be provided in the area of the occupied roof where such system is required elsewhere in the building.
  2. Assembly occupancies shall be permitted on roofs of open parking spaces of Type I or Type II construction, in accordance with the exception to Section 903.2.1.6.
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503.1.4.1 Enclosures Over Occupied Roof Areas

Elements or structures enclosing the occupied roof areas shall not extend more than 48 inches (1220 mm) above the surface of the occupied roof.
Exception: Penthouses constructed in accordance with Section 1511.2 and towers, domes, spires and cupolas constructed in accordance with Section 1511.5.

Section 504 Building Height and Number of Stories

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504.1 General

The height, in feet, and the number of stories of a building shall be determined based on the type of construction, occupancy classification and whether there is an automatic sprinkler system installed throughout the building.
Exception: The building height of one-story aircraft hangars, aircraft paint hangars and buildings used for the manufacturing of aircraft shall not be limited where the building is provided with an automatic sprinkler system or automatic fire-extinguishing system in accordance with Chapter 9 and is entirely surrounded by public ways or yards not less in width than one and one-half times the building height.
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504.1.1 Unlimited Area Buildings

The height of unlimited area buildings shall be designed in accordance with Section 507.
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504.1.2 Special Provisions

The special provisions of Section 510 permit the use of special conditions that are exempt from, or modify, the specific requirements of this chapter regarding the allowable heights of buildings based on the occupancy classification and type of construction, provided the special condition complies with the provisions specified in Section 510.
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504.2 Mixed Occupancy

In a building containing mixed occupancies in accordance with Section 508, no individual occupancy shall exceed the height and number of story limits specified in this section for the applicable occupancies.

504.3 Height in Feet

The maximum height, in feet, of a building shall not exceed the limits specified in Table 504.3.
Exception: Towers, spires, steeples and other rooftop structures shall be constructed of materials consistent with the required type of construction of the building except where other construction is permitted by Section 1511.2.4. Such structures shall not be used for habitation or storage. The structures shall be unlimited in height where of noncombustible materials and shall not extend more than 20 feet (6096 mm) above the allowable building height where of combustible materials (see Chapter 15 for additional requirements).
TABLE 504.3
ALLOWABLE BUILDING HEIGHT IN FEET ABOVE GRADE PLANE a, i
OCCUPANCY
CLASSIFICATION
 TYPE OF CONSTRUCTION
See Footnotes Type I Type II Type III Type IV Type V
A B A B A B A B C HT A B
B, F, M, S, U NSb UL 160 65 55 65 55 65 65 65 65 50 40
S UL 180 85 75 85 75 270 180 85 85 70 60
A, E NSb UL 160 65 55 65 55 65 65 65 65 50 40
S (without area increase) UL 180 85 75 85 75 270 180 85 85 70 60
S (with area increase) UL 160 65 55 65 55 250 160 65 65 50 40
H-1, H-2, H-3, H-5, L NSc, d UL 160 65 55 65 55 120 90 85 65 50 40
S (without area increase)
S (with area increase) UL 160 65 55 65 55 65 50 40
H-4 NSc, d UL 160 65 55 65 55 65 65 65 65 50 40
S (without area increase) UL 180 85 75 85 75 140 100 85 85 70 60
S (with area increase) UL 160 65 55 65 55 120 160 65 65 50 40
I-3 NSd, e UL 160 NP NP NP NP NP NP NP NP NP NP
S (without area increase) UL 180 NP NP NP NP NP NP NP NP NP NP
S (with area increase) UL 160 NP NP NP NP NP NP NP NP NP NP
I-2, I-2.1 NSd, e, f UL 160 65 55 65 55 NP NP NP 65 50 40
S (without area increase) UL 180 85 NP NP NP
S (with area increase) UL 160 65 NP NP NP
I-4 NSd, g UL 160 65 55 65 55 65 65 65 65 50 40
S (without area increase) UL 180 85 75 85 75 180 120 85 85 70 60
S (with area increase) UL 160 65 55 65 55 160 100 65 65 50 50
R-1h NSd UL 160 65 55 65 55 65 65 65 65 50 40
S13D 60 60 60 60 60 60 60 60 60 60 50 40
S13R 60 60 60 55 60 55 60 60 60 60 60 60
S (without area increase) UL 180 85 75 85 75 270 180 85 85 70 60
S (with area increase) UL 160 65 55 65 55 250 160 65 65 50 40
R-2h NSd UL 160 65 55 65 55 65 65 65 65 50 40
S13R 60 60 60 55 60 55 60 60 60 60 50 40
S (without area increase) UL 180 85 75 85 75 270 180 85 85 70 60
S (with area increase) UL 160 65 55 65 55 250 160 65 65 60 j 40
R-2.1h NSd UL 160 65 55 65 55 65 NP NP NP 50 40
S13D 60 60 60 55 60 55 60 NP NP NP 50 40
S13R 60 60 60 55 60 55 60 NP NP NP 50 40
S UL 160 65 55 65 55 270 NP NP NP 50 40
R-2.2h NSd NP NP NP NP NP NP NP NP NP NP NP NP
S (without area increase) UL 180 85 NP 85 NP 270 180 85 85 70 NP
S (with area increase) UL 160 65 NP 65 NP 250 160 65 65 60 i NP
R-3, R-3.1h NSd UL 160 65 55 65 55 65 65 65 65 50 40
S13D 60 60 60 60 60 60 60 60 60 60 50 40
S13R 60 60 60 55 60 55 60 60 60 60 60 60
S UL 160 65 55 65 55 270 180 85 65 70 60
R-4h NSd UL 160 65 55 65 55 65 65 65 65 50 40
S13D 60 60 60 55 60 55 60 60 60 60 50 40
S13R 60 60 60 55 60 55 60 60 60 60 50 40
S UL 160 65 55 65 55 270 180 85 65 50 40
For SI: 1 foot = 304.8 mm.
UL = Unlimited; NP = Not Permitted; NS = Buildings not equipped throughout with an automatic sprinkler system; S = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1; S13R = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.2; S13D = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.3.
  1. See Chapters 4 and 5 for specific exceptions to the allowable height in this chapter.
  2. See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies.
  3. New Group H and all Group L occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5.
  4. The NS value is only for use in evaluation of existing building height in accordance with the California Existing Building Code.
  5. New Group I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
  6. New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
  7. For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
  8. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
  9. In other than Group A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, the S increases for height and stories in Tables 504.3 and 504.4 are permitted in addition to the S area increase in accordance with Table 506.2.
  10. For Group R-2 buildings of Type VA construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1, S area increase is permitted in addition to the height and story increase provided the height shall not exceed 60 feet and 4 stories.
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504.4 Number of Stories

The maximum number of stories above grade plane of a building shall not exceed the limits specified in Table 504.4.
TABLE 504.4
ALLOWABLE NUMBER OF STORIES ABOVE GRADE PLANEa, b, n
OCCUPANCY
CLASSIFICATION
 TYPE OF CONSTRUCTION
See Footnotes Type I Type II Type III Type IV Type V
A B A B A B A B C HT A B
A-1 NS UL 5 3 2 3 2 3 3 3 3 2 1
S (without area increase) UL 6 4 3 4 3 9 6 4 4 3 2
S (with area increase) UL 5 3 2 3 2 8 5 3 3 2 1
A-2 NS UL 11 3 2 3 2 3 3 3 3 2 1
S (without area increase) UL 12 4 3 4 3 18 12 6 4 3 2
S (with area increase) UL 11 3 2 3 2 17 11 5 3 2 1
A-3 NS UL 11 3 2 3 2 3 3 3 3 2 1
S (without area increase) UL 12 4 3 4 3 18 12 6 4 3 2
S (with area increase) UL 11 3 2 3 2 17 11 5 3 2 1
A-4 NS UL 11 3 2 3 2 3 3 3 3 2 1
S (without area increase) UL 12 4 3 4 3 18 12 6 4 3 2
S (with area increase) UL 11 3 2 3 2 17 11 5 3 2 1
A-5 NS UL UL UL UL UL UL 1 1 1 UL UL UL
S UL UL UL UL UL UL UL UL UL UL UL UL
B NS UL 11 5 3 5 3 5 5 5 5 3 2
S UL 12 6 4 6 4 18 12 9 6 4 3
E NS UL 5 3 2 3 2 3 3 3 3 1 1
S (without area increase) UL 6 4 3 4 3 9 6 4 4 2 2
S (with area increase) UL 5 3 2 3 2 8 7 3 3 1 1
F-1 NS UL 11 4 2 3 2 3 3 3 4 2 1
S UL 12 5 3 4 3 10 7 5 5 3 2
F-2 NS UL 11 5 3 4 3 5 5 5 5 3 2
S UL 12 6 4 5 4 12 8 6 6 4 3
H-1 NSc, d 1 1 1 1 1 1 NP NP NP 1 1 NP
S 1 1 1
H-2 NSc, d 20 3 2 1 2 1 1 1 1 2 1 1
S 2 2 2
H-3 NSc, d 20 6 4 2 4 2 3 3 3 4 2 1
S 4 4 4
H-4 NSc, d 20 7 5 3 5 3 5 5 5 5 3 2
S (without area increase) 20 8 6 4 6 4 8 7 6 6 4 3
S (with area increase) 20 7 5 3 5 3 7 6 5 5 3 2
H-5 NSc, d 4 4 3 3 3 3 2 2 2 3 3 2
S 3 3 3
I-2, I-2.1 j, i NS d, f UL 4 2 1 1 NP NP NP NP 1 1 NP
S (without area increase) UL 5 3 NP NP NP
S (with area increase) UL 4 2 NP NP NP
I-3 NS d, e NP NP NP NP NP NP NP NP NP NP NP NP
S (without area increase) UL 3 NP NP NP NP NP NP NP NP NP NP
S (with area increase) UL 2 NP NP NP NP NP NP NP NP NP NP
I-4p NS d, g UL 5 3 2 3 2 3 3 3 3 1 1
S (without area increase) UL 6 4 3 4 3 9 6 4 4 2 2
S (with area increase) UL 5 3 2 3 2 8 5 3 3 1 1
L NS NP NP NP NP NP NP NP NP NP NP NP NP
S 20 6 5 3 5 3 8 6 5 5 3 2
M NS UL 11 4 2 4 2 4 4 4 4 3 1
S UL 12 5 3 5 3 12 8 6 5 4 2
R-1h NSd UL 11 4 4 4 4 4 4 4 4 3 2
S13R 4 4 3 2
S (without area increase) UL 12 5 5 5 5 18 12 8 5 4 3
S (with area increase) UL 11 4 4 4 4 17 11 7 4 3 2
R-2h NSd UL 11 4 4 4 4 4 4 4 4 3 2
S13R 4 4 4 4 3
S (without area increase) UL 12 5 5 5 5 18 12 8 5 4 3
S (with area increase) UL 11 4 4 4 4 17 11 7 4 4o 2
R-2.1h NSd UL 6l 3k NP 3k NP 4 NP NP NP 3k NP
S13R UL 4l 3k NP 3k NP 4 NP NP NP 3k NP
S UL 6l 3k NP 3k NP 10 NP NP NP 3k NP
R-2.2h NSd NP NP NP NP NP NP NP NP NP NP NP NP
S (without area increase) UL 12 5 NP 5 NP 18 12 8 5 4 NP
S (with area increase) UL 11 4 NP 4 NP 17 11 7 4 4o NP
R-3, R-3.1h NSd UL 11 4 4 4 4 4 4 4 4 3 3
S13D 4 4 3 3
S13R 4 4 4 4
S UL 12 5 5 5 5 18 12 5 5 4 4
R-4h NSd UL 11l 4k 4m 4k 4m 4m 4m 4m 4m 3k 2m
S13D 4 4l 3k 2m
S13R 4 4l 4 3
S UL 11l 5 5 5 5 11l 5 5 5 4 3
S-1 NS UL 11 4 2 3 2 4 4 4 4 3 1
S UL 12 5 4 4 4 10 7 5 5 4 2
S-2i NS UL 11 5 3 4 3 4 4 4 5 4 2
S UL 12 6 4 5 4 12 8 5 6 5 3
U NS UL 5 4 2 3 2 4 4 4 4 2 1
S UL 6 5 3 4 3 9 6 5 5 3 2
UL = Unlimited; NP = Not Permitted; NS = Buildings not equipped throughout with an automatic sprinkler system; S = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1; S13R = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.2; S13D = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.3.
  1. See Chapters 4 and 5 for specific exceptions to the allowable height in this chapter.
  2. See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies.
  3. New Group H occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5.
  4. The NS value is only for use in evaluation of existing building height in accordance with the California Existing Building Code.
  5. Group I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
  6. New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6
    .
  7. For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
  8. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
  9. See Sections 407.1.1 and 408.1.2 for specific exceptions to construction type, allowable building areas and allowable heights.
  10. Restraint shall not be permitted in any building except in Group I-3 occupancies constructed for such use (see Section 408.1.2).
  11. Nonambulatory persons shall be limited to the first 2 stories.
  12. Nonambulatory persons shall be limited to the first 5 stories.
  13. Nonambulatory elderly clients are not permitted in buildings of these types of construction. See Sections 435.3.3 and 435.3.4.
  14. In other than Group A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, the S increases for height and stories in Tables 504.3 and 504.4 are permitted in addition to the S area increase in accordance with Table 506.2.
  15. For Group R-2 buildings of Type VA construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1, S area increase is permitted in addition to the height and story increase provided the height shall not exceed 60 feet and 4 stories.
  16. See Section 436.1 for additional regulations for child-care centers and adult day care.
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Section 505 Mezzanines and Equipment Platforms

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505.1 General

Mezzanines shall comply with Section 505.2. Equipment platforms shall comply with Section 505.3.

505.2 Mezzanines

A mezzanine or mezzanines in compliance with Section 505.2 shall be considered a portion of the story below. Such mezzanines shall not contribute to either the building area or number of stories as regulated by Section 503.1. The area of the mezzanine shall be included in determining the fire area. The clear height above and below the mezzanine floor construction shall be not less than 7 feet (2134 mm).
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505.2.1 Area Limitation

The aggregate area of a mezzanine or mezzanines within a room shall be not greater than one-third of the floor area of that room or space in which they are located. The enclosed portion of a room shall not be included in a determination of the floor area of the room in which the mezzanine is located. In determining the allowable mezzanine area, the area of the mezzanine shall not be included in the floor area of the room.
Exceptions:
  1. The aggregate area of mezzanines in buildings and structures of Type I or II construction for special industrial occupancies in accordance with Section 503.1.1 shall be not greater than two-thirds of the floor area of the room.
  2. The aggregate area of mezzanines in buildings and structures of Type I or II construction shall be not greater than one-half of the floor area of the room in buildings and structures equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1 and an approved emergency voice/alarm communication system in accordance with Section 907.5.2.2.
  3. The aggregate area of a mezzanine within a dwelling unit that is located in a building equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 shall not be greater than one-half of the floor area of the room, provided that:
    1. Except for enclosed closets and bathrooms, the mezzanine shall be open to the room in which such mezzanine is located;
    2. The opening to the room shall be unobstructed except for walls not more than 42 inches (1067 mm) in height, columns and posts; and
    3. Exceptions to Section 505.2.3 shall not be permitted.

505.2.1.1 Aggregate Area of Mezzanines and Equipment Platforms

Where a room contains both a mezzanine and an equipment platform, the aggregate area of the two raised floor levels shall be not greater than two-thirds of the floor area of that room or space in which they are located. The area of the mezzanine shall not exceed the area determined in accordance with Section 505.2.1.

505.2.2 Means of Egress

The means of egress for mezzanines shall comply with the applicable provisions of Chapter 10.

505.2.3 Openness

A mezzanine shall be open and unobstructed to the room in which such mezzanine is located except for walls not more than 42 inches (1067 mm) in height, columns and posts.
Exceptions:
  1. Mezzanines or portions thereof are not required to be open to the room in which the mezzanines are located, provided that the occupant load of the aggregate area of the enclosed space is not greater than 10.
  2. A mezzanine having two or more exits or access to exits is not required to be open to the room in which the mezzanine is located.
  3. Mezzanines or portions thereof are not required to be open to the room in which the mezzanines are located, provided that the aggregate floor area of the enclosed space is not greater than 10 percent of the mezzanine area.
  4. In industrial facilities, mezzanines used for control equipment are permitted to be glazed on all sides.
  5. In occupancies other than Groups H and I, which are no more than two stories above grade plane and equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, a mezzanine having two or more exits or access to exits shall not be required to be open to the room in which the mezzanine is located.
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505.3 Equipment Platforms

Equipment platforms in buildings shall not be considered as a portion of the floor below. Such equipment platforms shall not contribute to either the building area or the number of stories as regulated by Section 503.1. The area of the equipment platform shall not be included in determining the fire area in accordance with Section 903. Equipment platforms shall not be a part of any mezzanine and such platforms and the walkways, stairways, alternating tread devices and ladders providing access to an equipment platform shall not serve as a part of the means of egress from the building.
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505.3.1 Area Limitation

The aggregate area of all equipment platforms within a room shall be not greater than two-thirds of the area of the room in which they are located. Where an equipment platform is located in the same room as a mezzanine, the area of the mezzanine shall be determined by Section 505.2.1 and the combined aggregate area of the equipment platforms and mezzanines shall be not greater than two-thirds of the room in which they are located. The area of the mezzanine shall not exceed the area determined in accordance with Section 505.2.1.

505.3.2 Automatic Sprinkler System

Where located in a building that is required to be protected by an automatic sprinkler system, equipment platforms shall be fully protected by sprinklers above and below the platform, where required by the standards referenced in Section 903.3.
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505.3.3 Guards

Equipment platforms shall have guards where required by Section 1015.2.
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Section 506 Building Area

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506.1 General

The floor area of a building shall be determined based on the type of construction, occupancy classification, whether there is an automatic sprinkler system installed throughout the building and the amount of building frontage on public way or open space.
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506.1.1 Unlimited Area Buildings

Unlimited area buildings shall be designed in accordance with Section 507.

506.1.2 Special Provisions

The special provisions of Section 510 permit the use of special conditions that are exempt from, or modify, the specific requirements of this chapter regarding the allowable areas of buildings based on the occupancy classification and type of construction, provided the special condition complies with the provisions specified in Section 510.

506.1.3 Basements

Basements need not be included in the total allowable floor area of a building provided the total area of such basements does not exceed the area permitted for a one-story above grade plane building.

506.2 Allowable Area Determination

The allowable area of a building shall be determined in accordance with the applicable provisions of Sections 506.2.1, 506.2.2 and 506.3.
TABLE 506.2
ALLOWABLE AREA FACTOR (At = NS, S1, S13R, S13D or SM, as applicable) IN SQUARE FEETa, b, j
OCCUPANCY
CLASSIFICATION
 SEE FOOTNOTES TYPE OF CONSTRUCTION
Type I Type II Type III Type IV Type V
A B A B A B A B C HT A B
A-1 NS UL UL 15,500 8,500 14,000 8,500 45,000 30,000 18,750 15,000 11,500 5,500
S1 UL UL 62,000 34,000 56,000 34,000 180,000 120,000 75,000 60,000 46,000 22,000
SM (without height increase) UL UL 46,500 25,500 42,000 25,500 135,000 90,000 56,250 45,000 34,500 16,500
SM (with height increase) UL UL 15,500 8,500 14,000 8,500 45,000 30,000 18,750 15,000 11,500 5,500
A-2 NS UL UL 15,500 9,500 14,000 9,500 45,000 30,000 18,750 15,000 11,500 6,000
S1 UL UL 62,000 38,000 56,000 38,000 180,000 120,000 75,000 60,000 46,000 24,000
SM (without height increase) UL UL 46,500 28,500 42,000 28,500 135,000 90,000 56,250 45,000 34,500 18,000
SM (with height increase) UL UL 15,500 9,500 14,000 9,500 45,000 30,000 18,750 15,000 11,500 6,000
A-3 NS UL UL 15,500 9,500 14,000 9,500 45,000 30,000 18,750 15,000 11,500 6,000
S1 UL UL 62,000 38,000 56,000 38,000 180,000 120,000 75,000 60,000 46,000 24,000
SM (without height increase) UL UL 46,500 28,500 42,000 28,500 135,000 90,000 56,250 45,000 34,500 18,000
SM (with height increase) UL UL 15,500 9,500 14,000 9,500 45,000 30,000 18,750 15,000 11,500 6,000
A-4 NS UL UL 15,500 9,500 14,000 9,500 45,000 30,000 18,750 15,000 11,500 6,000
S1 UL UL 62,000 38,000 56,000 38,000 180,000 120,000 75,000 60,000 46,000 24,000
SM (without height increase) UL UL 46,500 28,500 42,000 28,500 135,000 90,000 56,250 45,000 34,500 18,000
SM (with height increase) UL UL 15,500 9,500 14,000 9,500 45,000 30,000 18,750 15,000 11,500 6,000
A-5 NS UL UL UL UL UL UL UL UL UL UL UL UL
S1
SM
B NS UL UL 37,500 23,000 28,500 19,000 108,000 72,000 45,000 36,000 18,000 9,000
S1 UL UL 150,000 92,000 114,000 76,000 432,000 288,000 180,000 144,000 72,000 36,000
SM UL UL 112,500 69,000 85,500 57,000 324,000 216,000 135,000 108,000 54,000 27,000
E NS UL UL 26,500 14,500 23,500 14,500 76,500 51,000 31,875 25,500 18,500 9,500
S1 UL UL 106,000 58,000 94,000 58,000 306,000 204,000 127,500 102,000 74,000 38,000
SM (without height increase) UL UL 79,500 43,500 70,500 43,500 229,500 153,000 95,625 76,500 55,500 28,500
SM (with height increase) UL UL 26,500 14,500 23,500 14,500 76,500 51,000 31,875 25,500 18,500 9.500
F-1 NS UL UL 25,000 15,500 19,000 12,000 100,500 67,000 41,875 33,500 14,000 8,500
S1 UL UL 100,000 62,000 76,000 48,000 402,000 268,000 167,500 134,000 56,000 34,000
SM UL UL 75,000 46,500 57,000 36,000 301,500 201,000 125,625 100,500 42,000 25,500
F-2 NS UL UL 37,500 23,000 28,500 18,000 151,500 101,000 63,125 50,500 21,000 13,000
S1 UL UL 150,000 92,000 114,000 72,000 606,000 404,000 252,500 202,000 84,000 52,000
SM UL UL 112,500 69,000 85,500 54,000 454,500 303,000 189,375 151,500 63,000 39,000
H-1 NSc 21,000 16,500 11,000 7,000 9,500 7,000 10,500 10,500 10,500 10,500 7,500 NP
S1
H-2 NSc 21,000 16,500 11,000 7,000 9,500 7,000 10,500 10,500 10,500 10,500 7,500 3,000
S1
SM
H-3 NSc UL 60,000 26,500 14,000 17,500 13,000 25,500 25,500 25,500 25,500 10,000 5,000
S1
SM
H-4 NSc, d UL UL 37,500 17,500 28,500 17,500 72,000 54,000 40,500 36,000 18,000 6,500
S1 UL UL 150,000 70,000 114,000 70,000 288,000 216,000 162,000 144,000 72,000 26,000
SM (without height increase) UL UL 112,500 52,500 85,500 52,500 216,000 162,000 121,500 108,000 54,000 19,500
SM (with height increase) UL UL 37,500 17,500 28,500 17,500 72,000 54,000 40,500 36,000 18,000 6,500
H-5 NSc, d UL UL 37,500 23,000 28,500 19,000 72,000 54,000 40,500 36,000 18,000 9,000
S1 UL UL 150,000 92,000 114,000 76,000 288,000 216,000 162,000 144,000 72,000 36,000
SM (without height increase) UL UL 112,500 69,000 85,500 57,000 216,000 162,000 121,500 108000 54,000 27,000
SM (with height increase) UL UL 37,500 23,000 28,500 19,000 72,000 54,000 40,500 36,000 18,000 9,000
I-2, I-2.1 NSd, f UL UL 15,000 11,000 12,000 NP NP NP NP 12,000 9,500 NP
S1 UL UL 60,000 44,000 48,000 NP NP NP NP 48,000 38,000 NP
SM (without height increase) UL UL 45,000 33,000 36,000 NP NP NP NP 36,000 28,500 NP
SM (with height increase) UL UL 15,000 11,000 12,000 NP NP NP NP 12,000 9,500 NP
I-3 NSd, e UL 15,100 NP NP NP NP NP NP NP NP NP NP
S1 UL 45,300 NP NP NP NP NP NP NP NP NP NP
SM (without height increase) UL 30,200 NP NP NP NP NP NP NP NP NP NP
SM (with height increase) UL 15,100 NP NP NP NP NP NP NP NP NP NP
I-4 NSd, g UL 60,500 26,500 13,000 23,500 13,000 76,500 51,000 25,500 25,500 18,500 9,000
S1 UL 121,000 106,000 52,000 94,000 52,000 306,000 204,000 102,000 102,000 74,000 36,000
SM (without height increase) UL 181,500 79,500 39,000 70,500 39,000 229,500 153,000 76,500 76,500 55,500 27,000
SM (with height increase) UL 60,500 26,500 13,000 23,500 13,000 76,500 51,000 25,500 25,500 18,500 9,000
L NSc UL 60,000 37,500 17,500 28,500 17,500 60,000 37,500 36,000 36,000 18,000 6,500
S1
SM
M NS UL UL 21,500 12,500 18,500 12,500 61,500 41,000 25,625 20,500 14,000 9,000
S1 UL UL 86,000 50,000 74,000 50,000 246,000 164,000 102,500 82,000 56,000 36,000
SM UL UL 64,500 37,500 55,500 37,500 184,500 123,000 76,875 61,500 42,000 27,000
R-1h NSd UL UL 24,000 16,000 24,000 16,000 61,500 41,000 25,625 20,500 12,000 7,000
S13R
S1 UL UL 96,000 64,000 96,000 64,000 246,000 164,000 102,500 82,000 48,000 28,000
SM (without height increase) UL UL 72,000 48,000 72,000 48,000 184,500 123,000 76,875 61,500 36,000 21,000
SM (with height increase) UL UL 24,000 16,000 24,000 16,000 61,500 41,000 25,625 20,500 12,000 7,000
R-2h NSd UL UL 24,000 16,000 24,000 16,000 61,500 41,000 25,625 20,500 12,000 7,000
S13R
S1 UL UL 96,000 64,000 96,000 64,000 246,000 164,000 102,500 82,000 48,000 28,000
SM (without height increase) UL UL 72,000 48,000 72,000 48,000 184,500 123,000 76,875 61,500 36,000 21,000
SM (with height increase) UL UL 24,000 16,000 24,000 16,000 61,500 41,000 25,625 20,500 12,000 7,000
R-2 Type VA
constructionk
 NSd NP NP NP NP NP NP NP NP NP NP 12,000 NP
S13R NP NP NP NP NP NP NP NP NP NP 12,000 NP
S1 NP NP NP NP NP NP NP NP NP NP 48,000 NP
SM (without height increase) NP NP NP NP NP NP NP NP NP NP 36,000 NP
SM (with height increase) NP NP NP NP NP NP NP NP NP NP 36,000j NP
R-2.1h NS d UL 55,000 19,000 NP 16,500 NP 54,000 NP NP NP 10,500 NP
S13R UL 55,000 19,000 NP 16,500 NP 10,500 NP
S1 UL 220,000 76,000 NP 66,000 NP 216,000 NP NP NP 42,000 NP
SM (without height increase) UL 165,000 57,000 NP 49,500 NP 162,000 NP NP NP 31,500 NP
SM (with height increase) UL 55,000 19,000 NP 16,500 NP 54,000 NP NP NP 10,500 NP
R-2.2h NS l UL UL 24,000 NP 24,000 NP 61,500 41,000 25,625 20,500 12,000 NP
S1 UL UL 96,000 NP 96,000 NP 246,000 164,000 102,500 82,000 48,000 NP
SM (without height increase) UL UL 72,000 NP 72,000 NP 184,500 123,000 76,875 61,500 36,000 NP
SM (with height increase) UL UL 24,000 NP 24,000 NP 61,500 41,000 25,625 20,500 12,000 NP
R-3, R-3-1h NSd UL UL UL UL UL UL UL UL UL UL UL UL
S13D
S13R
S1
SM
R-4h NSd UL UL 24,000 16,000 24,000 16,000 61,500 41,000 25,625 20,500 12,000 7,000
S13D
S13R
S1 UL UL 96,000 64,000 96,000 64,000 246,000 164,000 102,500 82,000 48,000 28,000
SM (without height increase) UL UL 72,000 48,000 72,000 48,000 184,500 123,000 76,875 61,500 36,000 21,000
SM (with height increase) UL UL 24,000 16,000 24,000 16,000 61,500 41,000 25,625 20,500 12,000 7,000
S-1 NS UL 48,000 26,000 17,500 26,000 17,500 76,500 51,000 31,875 25,500 14,000 9,000
S1 UL 192,000 104,000 70,000 104,000 70,000 306,000 204,000 127,500 102,000 56,000 36,000
SM UL 144,000 78,000 52,500 78,000 52,500 229,500 153,000 95,625 76,500 42,000 27,000
S-2 NS UL 79,000 39,000 26,000 39,000 26,000 115,500 77,000 48,125 38,500 21,000 13,500
S1 UL 316,000 156,000 104,000 156,000 104,000 462,000 308,000 192,500 154,000 84,000 54,000
SM UL 237,000 117,000 78,000 117,000 78,000 346,500 231,000 144,375 115,500 63,000 40,500
U NSi UL 35,500 19,000 8,500 14,000 8,500 54,000 36,000 22,500 18,000 9,000 5,500
S1 UL 142,000 76,000 34,000 56,000 34,000 216,000 144,000 90,000 72,000 36,000 22,000
SM UL 106,500 57,000 25,500 42,000 25,500 162,000 108,000 67,500 54,000 27,000 16,500
For SI: 1 square foot = 0.0929 m2.
UL = Unlimited; NP = Not Permitted; NS = Buildings not equipped throughout with an automatic sprinkler system; S1 = Buildings a maximum of one story above grade plane equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1; SM = Buildings two or more stories above grade plane equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1; S13R = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.2; S13D = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.3.
  1. See Chapters 4 and 5 for specific exceptions to the allowable area in this chapter.
  2. See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies.
  3. New Group H and all Group L occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5.
  4. The NS value is only for use in evaluation of existing building area in accordance with the California Existing Building Code.
  5. Group I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
  6. New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
  7. New Group I-4 occupancies see Exceptions 2 and 3 of Section 903.2.6.
  8. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
  9. The maximum allowable area for a single-story nonsprinklered Group U greenhouse is permitted to be 9,000 square feet, or the allowable area shall be permitted to comply with Table C102.1 of Appendix C.
  10. In other than Group A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, the S increases for height and stories in Tables 504.3 and 504.4 are permitted in addition to the S area increase in accordance with Table 506.2.
  11. For Group R-2 buildings of Type VA construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1, S area increase is permitted in addition to the height and story increase provided the height shall not exceed 60 feet and 4 stories.
  12. The NS value is only for use in evaluation of single-occupancy, multistory buildings per the formula in Section 506.2.3.
Upcodes Diagrams

506.2.1 Single-Occupancy Buildings

The allowable area of each story of a single-occupancy building shall be determined in accordance with Equation 5-1:
(Equation 5-1)
where:
Aa = Allowable area (square feet).
At = Tabular allowable area factor (NS, S1, S13R or S13D value, as applicable) in accordance with Table 506.2.
NS = Tabular allowable area factor in accordance with Table 506.2 for nonsprinklered building (regardless of whether the building is sprinklered).
If = Area factor increase due to frontage (percent) as calculated in accordance with Section 506.3.
The allowable area per story of a single-occupancy building with a maximum of three stories above grade shall be determined by Equation 5-1. The total allowable area of a single-occupancy building more than three stories above grade plane shall be determined in accordance with Equation 5-2:
(Equation 5-2)
where:
Aa = Allowable area (square feet).
At = Tabular allowable area factor (NS, S13R, S13D or SM value, as applicable) in accordance with Table 506.2.
NS = Tabular allowable area factor in accordance with Table 506.2 for a nonsprinklered building (regardless of whether the building is sprinklered).
If = Area factor increase due to frontage (percent) as calculated in accordance with Section 506.3.
Sa = For other than Group A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, actual number of stories above grade plane exceeds three. For Group A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, actual number of building stories above grade plane, not to exceed two.
Sa = 4 where the building is equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.2.
The actual area of any individual floor shall not exceed the allowable area per Equation 5-1.

506.2.2 Mixed-Occupancy Buildings

The allowable area of each story of a mixed-occupancy building shall be determined in accordance with the applicable provisions of, Section 508.3.2 for nonseparated occupancies and Section 508.4.2 for separated occupancies.
For buildings with more than three stories above grade plane, the total building area shall be such that the aggregate sum of the ratios of the actual area of each story divided by the allowable area of such stories, determined in accordance with Equation 5-3 based on the applicable provisions of Section 508.1, shall not exceed three, provided the aggregate sum of the ratios for portions of mixed-occupancy, multistory buildings containing A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, including any other associated non-separated occupancies, shall not exceed two.
(Equation 5-3)
Aa = Allowable area (square feet).
At = Tabular allowable area factor (NS, S13R, S13D or SM value, as applicable) in accordance with Table 506.2.
NS = Tabular allowable area factor in accordance with Table 506.2 for a nonsprinklered building, regardless of whether the building is sprinklered.
If = Area factor increase due to frontage (percent) as calculated in accordance with Section 506.3.
Upcodes Diagrams

506.2.2.1 Group H-2 or H-3 Mixed Occupancies

For a building containing Group H-2 or H-3 occupancies, the allowable area shall be determined in accordance with Section 508.4.2, with the sprinkler system increase applicable only to the portions of the building not classified as Group H-2 or H-3.

506.3 Frontage Increase

Every building shall adjoin or have access to a public way to receive an area factor increase based on frontage. Area factor increase shall be determined in accordance with Sections 506.3.1 through 506.3.3.
Upcodes Diagrams

506.3.1 Minimum Percentage of Perimeter

To qualify for an area factor increase based on frontage, a building shall have not less than 25 percent of its perimeter on a public way or open space. Such open space shall be either on the same lot or dedicated for public use and shall be accessed from a street or approved fire lane.

506.3.2 Minimum Frontage Distance

To qualify for an area factor increase based on frontage, the public way or open space adjacent to the building perimeter shall have a minimum distance (W) of 20 feet (6096 mm) measured at right angles from the building face to any of the following:
  1. The closest interior lot line.
  2. The entire width of a street, alley or public way.
  3. The exterior face of an adjacent building on the same property.
The frontage increase shall be based on the smallest public way or open space that is 20 feet (6096 mm) or greater, and the percentage of building perimeter having a minimum 20 feet (6096 mm) public way or open space.

506.3.3 Amount of Increase

The area factor increase based on frontage shall be determined in accordance with Table 506.3.3.
TABLE 506.3.3
FRONTAGE INCREASE FACTORa
PERCENTAGE OF
BUILDING PERIMETER
 OPEN SPACE (feet)
0 to less than 20 20 to less than 25 25 to less than 30 30 or greater
0 to less than 25 0 0 0 0
25 to less than 50 0 0.17 0.21 0.25
50 to less than 75 0 0.33 0.42 0.50
75 to 100 0 0.50 0.63 0.75
  1. Interpolation is permitted.
Upcodes Diagrams

506.3.3.1 Section 507 Buildings

Where a building meets the requirements of Section 507, as applicable, except for compliance with the minimum 60-foot (18 288 mm) public way or yard requirement, the area factor increase based on frontage shall be determined in accordance with Table 506.3.3.1.
TABLE 506.3.3.1
SECTION 507 BUILDINGSa
PERCENTAGE OF
BUILDING PERIMETER
 OPEN SPACE (feet)
30 to less than 35 35 to less than 40 40 to less than 45 45 to less than 50 50 to less than 55 55 to less than 60
0 to less than 25 0 0 0 0 0 0
25 to less than 50 0.29 0.33 0.38 0.42 0.46 0.50
50 to less than 75 0.58 0.67 0.75 0.83 0.92 1.00
75 to 100 0.88 1.00 1.13 1.25 1.38 1.50
  1. Interpolation is permitted.

Section 507 Unlimited Area Buildings

Upcodes Diagrams

507.1 General

The area of buildings of the occupancies and configurations specified in Sections 507.1 through 507.13 shall not be limited. Basements not more than one story below grade plane shall be permitted.

507.1.1 Accessory Occupancies

Accessory occupancies shall be permitted in unlimited area buildings in accordance with the provisions of Section 508.2, otherwise the requirements of Sections 507.3 through 507.13 shall be applied, where applicable.
Upcodes Diagrams

507.2 Measurement of Open Spaces

Where Sections 507.3 through 507.13 require buildings to be surrounded and adjoined by public ways and yards, those open spaces shall be determined as follows:
  1. Yards shall be measured from the building perimeter in all directions to the closest interior lot lines or to the exterior face of an opposing building located on the same lot, as applicable.
  2. Where the building fronts on a public way, the entire width of the public way shall be used.
Upcodes Diagrams

507.2.1 Reduced Open Space

The public ways or yards of 60 feet (18 288 mm) in width required in Sections 507.3, 507.4, 507.5, 507.6 and 507.12 shall be permitted to be reduced to not less than 40 feet (12 192 mm) in width, provided that the following requirements are met:
  1. The reduced width shall not be allowed for more than 75 percent of the perimeter of the building.
  2. The exterior walls facing the reduced width shall have a fire-resistance rating of not less than 3 hours.
  3. Openings in the exterior walls facing the reduced width shall have opening protectives with a fire protection rating of not less than 3 hours.

507.3 Nonsprinklered, One-Story Buildings

The area of a Group F-2 or S-2 building not more than one story in height shall not be limited where the building is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

507.4 Sprinklered, One-Story Buildings

The area of a Group A-4 building not more than one story above grade plane of other than Type V construction, or the area of a Group B, F, M or S building no more than one story above grade plane of any construction type, shall not be limited where the building is provided with an automatic sprinkler system throughout in accordance with Section 903.3.1.1 and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.
Exceptions:
  1. Buildings and structures of Type I or II construction for rack storage facilities that do not have access by the public shall not be limited in height, provided that such buildings conform to the requirements of Sections 507.4 and 903.3.1.1 and Chapter 32 of the California Fire Code.
  2. The automatic sprinkler system shall not be required in areas occupied for indoor participant sports, such as tennis, skating, swimming and equestrian activities in occupancies in Group A-4, provided that the following criteria are met:
    1. Exit doors directly to the outside are provided for occupants of the participant sports areas.
    2. The building is equipped with a fire alarm system with manual fire alarm boxes installed in accordance with Section 907.
    3. An automatic sprinkler system is provided in storage rooms, press boxes, concession booths or other spaces ancillary to the sport activity space.

507.4.1 Mixed Occupancy Buildings With Groups A-1 and A-2

Group A-1 and A-2 occupancies of other than Type V construction shall be permitted within mixed occupancy buildings of unlimited area complying with Section 507.4, provided that the following criteria are met:
  1. Group A-1 and A-2 occupancies are separated from other occupancies as required for separated occupancies in Section 508.4.4 with no reduction allowed in the fire-resistance rating of the separation based upon the installation of an automatic sprinkler system.
  2. Each area of the portions of the building used for Group A-1 or A-2 occupancies shall not exceed the maximum allowable area permitted for such occupancies in Section 503.1.
  3. Exit doors from Group A-1 and A-2 occupancies shall discharge directly to the exterior of the building.

507.5 Two-Story Buildings

The area of a Group B, F, M or S building not more than two stories above grade plane shall not be limited where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

507.6 Group A-3 Buildings of Type II Construction

The area of a Group A-3 building not more than one story above grade plane, used as a place of religious worship, community hall, dance hall, exhibition hall, gymnasium, lecture hall, indoor swimming pool or tennis court of Type II construction, shall not be limited provided that the following criteria are met:
  1. The building shall not have a stage other than a platform.
  2. The building shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
  3. The building shall be surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

507.7 Group A-3 Buildings of Type III and IV Construction

The area of a Group A-3 building of Type III or IV construction, with not more than one story above grade plane and used as a place of religious worship, community hall, dance hall, exhibition hall, gymnasium, lecture hall, indoor swimming pool or tennis court, shall not be limited provided that the following criteria are met:
  1. The building shall not have a stage other than a platform.
  2. The building shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
  3. The assembly floor shall be located at or within 21 inches (533 mm) of street or grade level and all exits are provided with ramps complying with Section 1012 to the street or grade level.
  4. The building shall be surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

507.8 Group H-2, H-3 and H-4 Occupancies

Group H-2, H-3 and H-4 occupancies shall be permitted in unlimited area buildings containing Group F or S occupancies in accordance with Sections 507.4 and 507.5 and the provisions of Sections 507.8.1 through 507.8.4.
Upcodes Diagrams

507.8.1 Allowable Area

The aggregate floor area of Group H occupancies located in an unlimited area building shall not exceed 10 percent of the area of the building nor the area limitations for the Group H occupancies as specified in Section 506 based on the perimeter of each Group H floor area that fronts on a public way or open space.

507.8.1.1 Located Within the Building

The aggregate floor area of Group H occupancies not located at the perimeter of the building shall not exceed 25 percent of the area limitations for the Group H occupancies as specified in Section 506.

507.8.1.1.1 Rooms for Flammable or Combustible Liquid Use, Dispensing or Mixing in Open Systems

Rooms for flammable or combustible liquid use, dispensing or mixing in open systems having a floor area of not more than 500 square feet (46.5 m2) need not be located on the outer perimeter of the building where they are in accordance with the California Fire Code and NFPA 30.

507.8.1.1.2 Liquid Storage Rooms and Rooms for Flammable or Combustible Liquid Use in Closed Systems

Liquid storage rooms and rooms for flammable or combustible liquid use in closed systems having a floor area of not more than 1,000 square feet (93 m2) need not be located on the outer perimeter where they are in accordance with the California Fire Code and NFPA 30.

507.8.1.1.3 Spray Paint Booths

Spray paint booths that comply with the California Fire Code need not be located on the outer perimeter.

507.8.2 Located on Building Perimeter

Except as provided for in Section 507.8.1.1, Group H occupancies shall be located on the perimeter of the building. In Group H-2 and H-3 occupancies, not less than 25 percent of the perimeter of such occupancies shall be an exterior wall.

507.8.3 Occupancy Separations

Group H occupancies shall be separated from the remainder of the unlimited area building and from each other in accordance with Table 508.4.

507.8.4 Height Limitations

For two-story, unlimited area buildings, Group H occupancies shall not be located more than one story above grade plane unless permitted based on the allowable height and number of stories and feet as specified in Section 504 based on the type of construction of the unlimited area building.

507.9 Unlimited Mixed Occupancy Buildings With Group H-5

The area of a Group B, F, H-5, M or S building not more than two stories above grade plane shall not be limited where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width, provided that the following criteria are met:
  1. Buildings containing Group H-5 occupancy shall be of Type I or II construction.
  2. Each area used for Group H-5 occupancy shall be separated from other occupancies as required in Sections 415.11 and 508.4.
  3. Each area used for Group H-5 occupancy shall not exceed the maximum allowable area permitted for such occupancies in Section 503.1 including modifications of Section 506.
    Exception: Where the Group H-5 occupancy exceeds the maximum allowable area, the Group H-5 shall be subdivided into areas that are separated by 2-hour fire barriers.
Upcodes Diagrams

507.10 Aircraft Paint Hangar

The area of a Group H-2 aircraft paint hangar not more than one story above grade plane shall not be limited where such aircraft paint hangar complies with the provisions of Section 412.5 and is surrounded and adjoined by public ways or yards not less in width than one and one-half times the building height.
Upcodes Diagrams

507.11 Group E Buildings

The area of a Group E building not more than one story above grade plane, of Type II, IIIA or IV construction, shall not be limited provided that the following criteria are met:
  1. Each classroom shall have not less than two means of egress, with one of the means of egress being a direct exit to the outside of the building complying with Section 1022.
  2. The building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
  3. The building is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

507.12 Motion Picture Theaters

In buildings of Type II construction, the area of a motion picture theater located on the first story above grade plane shall not be limited where the building is provided with an automatic sprinkler system throughout in accordance with Section 903.3.1.1 and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

507.13 Covered and Open Mall Buildings and Anchor Buildings

The area of covered and open mall buildings and anchor buildings not exceeding three stories in height that comply with Section 402 shall not be limited.

Section 508 Mixed Use and Occupancy

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508.1 General

Each portion of a building shall be individually classified in accordance with Section 302.1. Where a building contains more than one occupancy group, the building or portion thereof shall comply with the applicable provisions of Section 508.2, 508.3, 508.4 or 508.5, or a combination of these sections.
Exceptions:
  1. Occupancies separated in accordance with Section 510.
  2. Where required by Table 415.6.5, areas of Group H-1, H-2 and H-3 occupancies shall be located in a detached building or structure.

508.2 Accessory Occupancies

Accessory occupancies are those occupancies that are ancillary to the main occupancy of the building or portion thereof. Accessory occupancies shall comply with the provisions of Sections 508.2.1 through 508.2.4.
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508.2.1 Occupancy Classification

Accessory occupancies shall be individually classified in accordance with Section 302.1. The requirements of this code shall apply to each portion of the building based on the occupancy classification of that space.
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508.2.2 Allowable Building Height

The allowable height and number of stories of the building containing accessory occupancies shall be in accordance with Section 504 for the main occupancy of the building.
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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 10 percent of the floor area of the story in which they are located and shall not exceed the tabular values for non sprinklered buildings in Table 506.2 for each such accessory occupancy.

508.2.4 Separation of Occupancies

No separation is required between accessory occupancies and the main occupancy.
Exceptions:
  1. Group H-2, H-3, H-4 and H-5 and L occupancies shall be separated from all other occupancies in accordance with Section 508.4.
  2. Group R-1, R-2, R-2.1, R-2.2 and R-3 dwelling units and sleeping units shall be separated from other dwelling or sleeping units and from accessory occupancies contiguous to them in accordance with the requirements of Section 420.
  3. Group I-2 and I-2.1 shall be separated from all other occupancies in accordance with Section 508.4.
    Exception: No separation is required between Group B, E and R-2 sleeping units accessory to Group I-2 and I-2.1 and covered exterior entrances required by Section 11B-206.4.10 or Section 1224.33.2.1 accessory to Group I-2.
  4. Group I-3 and vehicle sally-ports shall be separated from all other occupancies in accordance with Section 508.4.
    Exception: No separation is required between Group B, E, R-2 sleeping units and S-2 occupancies accessory to Group I-3 of Type I construction.

508.3 Nonseparated Occupancies

Buildings or portions of buildings that comply with the provisions of this section shall be considered as nonseparated occupancies.
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508.3.1 Occupancy Classification

Nonseparated occupancies shall be individually classified in accordance with Section 302.1. The requirements of this code shall apply to each portion of the building based on the occupancy classification of that space. In addition, the most restrictive provisions of Chapter 9 that apply to the nonseparated occupancies shall apply to the total nonseparated occupancy area.
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508.3.1.1 High-Rise Buildings

Where nonseparated occupancies occur in a high-rise building, the most restrictive requirements of Section 403 that apply to the nonseparated occupancies shall apply throughout the high-rise building.

508.3.2 Allowable Building Area, Height and Number of Stories

The allowable building area, height and number of stories 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.
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508.3.3 Separation

No separation is required between nonseparated occupancies.
Exceptions:
  1. Group H-2, H-3, H-4 and H-5, I-2, I-2.1 and L occupancies shall be separated from all other occupancies in accordance with Section 508.4.
  2. Group R-1, R-2, R-2.1, R-2.2 and R-3 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. Separation is required between Group I-3 and vehicle sally ports.
  4. Where Group I-3 is not the main occupancy and the area is greater than 10 percent of the floor area, it shall be separated per Table 508.4.

508.4 Separated Occupancies

Buildings or portions of buildings that comply with the provisions of this section shall be considered as separated occupancies.
TABLE 508.4
REQUIRED SEPARATION OF OCCUPANCIES (HOURS)h
OCCUPANCY A, E I-4i, R-2.1 I-2j, I-3 R-1a, R-2a,
R-3a, R-3.1a,
F-2, S-2b,
U
 Be, F-1g, h,
M, S-1
 L 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 S NS
A, E N N 2 2 2 NP 2 NP 1 2 N 1 1 2 2 NP NP NP 3 4 2 3 2 NP
I-4i, R-2.1 2 2 1e NP 2 NP 2 NP 1 NP 1 2 1 2 2 NP NP NP 4 NP 4 NP 4 NP
I-2j, I-2.1 2 NP 2 NP N NP 2 NP 2 NP 2 NP 2 NP 2 NP NP NP 4 NP 4 NP 4 NP
I-3 2 NP 2 NP 2 NP N NP 2 NP 2 2 2 2 2 NP NP NP 4 NP 4 NP 4 NP
R-1a, R-2a, R-3.1a, R-4a 1 2 1 NP 2 NP 2 NP N N 1c 2c 1 2 4 NP NP NP 3 NP 2 NP 2 NP
F-2, S-2b, U N 1 1 2 2 NP 2 2 1c 2c N N 1 2 1 NP NP NP 3 4 2 3 2 NP
Be, F-1g, h, M, S-1 1 2 1 2 2 NP 2 2 1 2 1 2 N N 1 NP NP NP 2 3 1 2 1 NP
L 2 NP 2 NP 2 NP 2 NP 4 NP 1 NP 1 NP 1 NP NP NP 2 NP 1 NP 1 NP
H-1 NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP N NP NP NP NP NP NP NP
H-2 3 4 4 NP 4 NP 4 NP 3 NP 3 4 2 3 2 NP NP NP N NP 1 NP 1 NP
H-3, H-4 2 3 4 NP 4 NP 4 NP 2 NP 2 3 1 2 1 NP NP NP 1 NP 1d NP 1 NP
H-5 2 NP 4 NP 4 NP 4 NP 2 NP 2 NP 1 NP 1 NP NP NP 1 NP 1 NP 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.
  1. See Section 420.
  2. The required separation from areas used only for private or pleasure vehicles shall be reduced by 1 hour but not to less than 1 hour.
  3. See Sections 406.3.2 and 406.6.4.
  4. Separation is not required between occupancies of the same classification.
  5. See Section 422.2 for ambulatory care facilities.
  6. 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.
  7. [SFM] Group I and F1 occupancies and Group R-2.1 and F-1 occupancies shall have a 3 hour separation.
  8. [SFM] Commercial kitchens not associated with cafeterias and similar dining facilities in Group I-2 and Group R-2.1 shall have a 2-hour separation and shall be protected by an automatic sprinkler system.
  9. [SFM] Group E child-care separation with I-4 child care can be reduced to 1 hour with the installation of automatic fire sprinklers in accordance with Section 903.3.1.1.
  10. When not considered an accessory use in accordance with Section 508.2.4, the required separation between Group I-2 and required covers for accessible entrances and emergency vehicle entrances, when in accordance with Section 406.5.2 and protected by an automatic sprinkler system, shall be reduced by 1 hour but not to less than 1 hour. See Section 903.2.21.
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508.4.1 Occupancy Classification

Separated occupancies shall be individually classified in accordance with Section 302.1. Each separated space shall comply with this code based on the occupancy classification of that portion of the building. The most restrictive provisions of Chapter 9 that apply to the separate occupancies shall apply to the total nonfire-barrier-separated occupancy areas. Occupancy separations that serve to define fire area limits established in Chapter 9 for requiring a fire protection system shall also comply with Section 901.7.

508.4.2 Allowable Building Area

In each story, the building area shall be such that the sum of the ratios of the actual building area of each separated occupancy divided by the allowable building area of each separated occupancy shall not exceed 1.

508.4.3 Allowable Building Height and Number of Stories

Each separated occupancy shall comply with the building height limitations and story limitations based on the type of construction of the building in accordance with Section 503.1.
Exception: Special provisions of Section 510 shall permit occupancies at building heights and number of stories other than provided in Section 503.1.
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508.4.4 Separation

Individual occupancies shall be separated from adjacent occupancies in accordance with Table 508.4.

508.4.4.1 Construction

Required separations shall be fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both, so as to completely separate adjacent occupancies. Mass timber elements serving as fire barriers or horizontal assemblies to separate occupancies in Type IV-B or IV-C construction shall be separated from the interior of the building with an approved thermal barrier consisting of gypsum board that is not less than 1/2 inch (12.7 mm) in thickness or a material that is tested in accordance with and meets the acceptance criteria of both the Temperature Transmission Fire Test and the Integrity Fire Test of NFPA 275.

508.5 Live/Work Units

A live/work unit shall comply with Sections 508.5 through 508.5.11.
Exceptions:
  1. Dwelling or sleeping units that include an office that is less than 10 percent of the area of the dwelling unit are permitted to be classified as dwelling units with accessory occupancies in accordance with Section 508.2.
  2. Live/work units complying with the requirements of Section 508.5 shall be permitted to be constructed as one- and two-family dwellings or townhouses in accordance with the California Residential Code, as applicable.

508.5.1 Limitations

The following shall apply to live/work areas:
  1. The live/work unit is permitted to be not greater than 3,000 square feet (279 m2) in area.
  2. The nonresidential area is permitted to be not more than 50 percent of the area of each live/work unit.
  3. The nonresidential area function shall be limited to the first or main floor only of the live/work unit.
  4. Not more than five nonresidential workers or employees are allowed to occupy the nonresidential area at any one time.

508.5.2 Occupancies

Live/work units shall be classified as a Group R-2 occupancy. Separation requirements found in Sections 420 and 508 shall not apply within the live/work unit where the live/work unit is in compliance with Section 508.5. Nonresidential uses that would otherwise be classified as either a Group H or S occupancy shall not be permitted in a live/work unit.
Exception: Storage shall be permitted in the live/work unit provided that the aggregate area of storage in the nonresidential portion of the live/work unit shall be limited to 10 percent of the space dedicated to nonresidential activities.

508.5.3 Means of Egress

Except as modified by this section, the means of egress components for a live/work unit shall be designed in accordance with Chapter 10 for the function served.
Exception: Residential areas of live/work units constructed in accordance with the California Residential Code shall not be required to comply with Chapter 10.

508.5.4 Egress Capacity

The egress capacity for each element of the live/work unit shall be based on the occupant load for the function served in accordance with Table 1004.5.

508.5.5 Spiral Stairways

Spiral stairways that conform to the requirements of Section 1011.10 shall be permitted.

508.5.6 Vertical Openings

Floor openings between floor levels of a live/work unit are permitted without enclosure.

[F] 508.5.7 Fire Protection

The live/work unit shall be provided with a monitored fire alarm system where required by Section 907.2.9 and an automatic sprinkler system in accordance with Section 903.2.8.

508.5.8 Structural

Floors within a live/work unit shall be designed for the live loads in Table 1607.1, based on the function within the space.
Exception: Residential areas of live/work units constructed in accordance with the California Residential Code shall not be required to comply with Table 1607.1.

508.5.9 Accessibility

Accessibility shall be designed in accordance with Chapter 11A and/or 11B, when applicable, for the function served.

508.5.10 Ventilation

The applicable ventilation requirements of the California Mechanical Code shall apply to each area within the live/work unit for the function within that space.

508.5.11 Plumbing Facilities

The nonresidential area of the live/work unit shall be provided with minimum plumbing facilities as specified by the California Plumbing Code, based on the function of the nonresidential area. Where the nonresidential area of the live/work unit is required to be accessible, the plumbing fixtures specified by the California Plumbing Code shall be accessible.

Section 509 Incidental Uses

509.1 General

Incidental uses located within single occupancy or mixed occupancy buildings shall comply with the provisions of this section. Incidental uses are ancillary functions associated with a given occupancy that generally pose a greater level of risk to that occupancy and are limited to those uses specified in Table 509.1.
Exception: Incidental uses within and serving a dwelling unit are not required to comply with this section.
[F] TABLE 509.1
INCIDENTAL USES
ROOM OR AREA SEPARATION AND/OR PROTECTION
Furnace room where any piece of equipment is over 400,000 Btu per hour input 1 hour or provide automatic sprinkler system
Rooms with boilers where the largest piece of equipment is over 15 psi and 10 horsepower 1 hour or provide automatic sprinkler system
Refrigerant machinery room 1 hour or provide automatic sprinkler system
Hydrogen fuel gas rooms, not classified as Group H 1 hour in Group B, F, M, S and U occupancies; 2 hours in Group A, E, I and R occupancies.
Incinerator rooms 2 hours and provide automatic sprinkler system
Paint shops, not classified as Group H, located in occupancies other than Group F 2 hours; or 1 hour and provide automatic sprinkler system
In Group E occupancies, laboratories and vocational shops not classified as Group H 1 hour or provide automatic sprinkler system
[SFM] Rooms or areas with special hazards such as laboratories, vocational shops and other such areas not classified as Group H, located in Group E occupancies where hazardous materials in quantities not exceeding the maximum allowable quantity are used or stored. 1 hour
In Group I-2 and I-2.1 occupancies, laboratories not classified as Group H 1 houra
In ambulatory care facilities, laboratories not classified as Group H 1 hour or provide automatic sprinkler system
Laundry rooms over 100 square feet 1 hour or provide automatic sprinkler system
In Group I-2 and I-2.1 laundry rooms over 100 square feet 1 houra
Group I-3 cells and Group I-2 and I-2.1 patient rooms equipped with padded surfaces 1 houra
In Group I-2 and I-2.1 physical plant maintenance shops 1 houra
In ambulatory care facilities or Group I-2 and I-2.1 occupancies, waste and linen collection rooms with containers that have an aggregate volume of 10 cubic feet or greater 1 houra
In other than ambulatory care facilities and Group I-2 and I-2.1 occupancies, waste and linen collection rooms over 100 square feet 1 hour or provide automatic sprinkler system
In ambulatory care facilities or Group I-2 and I-2.1 occupancies, storage rooms greater than 100 square feet 1 houra
Electrical installations and transformers See Sections 110.26 through 110.34 and Sections 450.8 through 450.48 of the California Electrical Code for protection and separation requirements.
For SI: 1 square foot = 0.0929 m2, 1 pound per square inch (psi) = 6.9 kPa, 1 British thermal unit (Btu) per hour = 0.293 watts, 1 horsepower = 746 watts, 1 gallon = 3.785 L, 1 cubic foot = 0.0283 m3.
  1. [SFM] Fire barrier protection and automatic sprinkler protection required throughout the fire area in I-2 and I-2.1 occupancies as indicated.

509.2 Occupancy Classification

Incidental uses shall not be individually classified in accordance with Section 302.1. Incidental uses shall be included in the building occupancies within which they are located.

509.3 Area Limitations

The aggregate floor area of incidental uses shall not occupy more than 10 percent of the building area of the story in which they are located.

509.4 Separation and Protection

The incidental uses specified in Table 509.1 shall be separated from the remainder of the building or equipped with an automatic sprinkler system, or both, in accordance with the provisions of that table.

509.4.1 Separation

Where Table 509.1 specifies a fire-resistance-rated separation, the incidental uses shall be separated from the remainder of the building by a fire barrier constructed in accordance with Section 707 or a horizontal assembly constructed in accordance with Section 711, or both. Construction supporting 1-hour fire barriers or horizontal assemblies used for incidental use separations in buildings of Type IIB, IIIB and VB construction is not required to be fire-resistance rated unless required by other sections of this code.
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509.4.1.1 Type IV-B and IV-C Construction

Where Table 509.1 specifies a fire-resistance-rated separation, mass timber elements serving as fire barriers or horizontal assemblies in Type IV-B or IV-C construction shall be separated from the interior of the incidental use with an approved thermal barrier consisting of gypsum board that is not less than 1/2 inch (12.7 mm) in thickness or a material that is tested in accordance with and meets the acceptance criteria of both the Temperature Transmission Fire Test and the Integrity Fire Test of NFPA 275.

509.4.2 Protection

Where Table 509.1 permits an automatic sprinkler system without a fire barrier, the incidental uses shall be separated from the remainder of the building by construction capable of resisting the passage of smoke. The walls shall extend from the top of the foundation or floor assembly below to the underside of the ceiling that is a component of a fire-resistance-rated floor assembly or roof assembly above or to the underside of the floor or roof sheathing, deck or slab above. Doors shall be self- or automatic-closing upon detection of smoke in accordance with Section 716.2.6.6. Doors shall not have air transfer openings and shall not be undercut in excess of the clearance permitted in accordance with NFPA 80. Walls surrounding the incidental use shall not have air transfer openings unless provided with smoke dampers in accordance with Section 710.8.

509.4.2.1 Protection Limitation

Where an automatic sprinkler system is provided in accordance with Table 509.1, only the space occupied by the incidental use need be equipped with such a system.

Section 510 Special Provisions

510.1 General

The provisions in Sections 510.2 through 510.9 shall permit the use of special conditions that are exempt from, or modify, the specific requirements of this chapter regarding the allowable building heights and areas of buildings based on the occupancy classification and type of construction, provided the special condition complies with the provisions specified in this section for such condition and other applicable requirements of this code. The provisions of Sections 510.2 through 510.8 are to be considered independent and separate from each other.
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510.2 Horizontal Building Separation Allowance

A building shall be considered as separate and distinct buildings for the purpose of determining area limitations, continuity of fire walls, limitation of number of stories and type of construction where the following conditions are met:
  1. The buildings are separated with a horizontal assembly having a fire-resistance rating of not less than 3 hours. Where vertical offsets are provided as part of a horizontal assembly, the vertical offset and the structure supporting the vertical offset shall have a fire-resistance rating of not less than 3 hours.
  2. The building below, including the horizontal assembly, is of Type IA construction.
  3. Shaft, stairway, ramp and escalator enclosures through the horizontal assembly shall have not less than a 2-hour fire-resistance rating with opening protectives in accordance with Section 716.
    Exception: Where the enclosure walls below the horizontal assembly have not less than a 3-hour fire-resistance rating with opening protectives in accordance with Section 716, the enclosure walls extending above the horizontal assembly shall be permitted to have a 1-hour fire-resistance rating, provided that the following conditions are met:
    1. The building above the horizontal assembly is not required to be of Type I construction.
    2. The enclosure connects fewer than four stories.
    3. The enclosure opening protectives above the horizontal assembly have a fire protection rating of not less than 1 hour.
  4. Interior exit stairways located within the Type IA building are permitted to be of combustible materials where the following requirements are met:
    1. The building above the Type IA building is of Type III, IV, or V construction.
    2. The stairway located in the Type IA building is enclosed by 3-hour fire-resistance-rated construction with opening protectives in accordance with Section 716.
  5. The building or buildings above the horizontal assembly shall be permitted to have multiple Group A occupancy uses, each with an occupant load of less than 300, or Group B, M, R or S occupancies.
  6. The building below the horizontal assembly shall be protected throughout by an approved automatic sprinkler system in accordance with Section 903.3.1.1, and shall be permitted to be any occupancy allowed by this code except Group H.
  7. The maximum building height in feet (mm) shall not exceed the limits set forth in Section 504.3 for the building having the smaller allowable height as measured from the grade plane.

510.3 Group S-2 Enclosed Parking Garage With Group S-2 Open Parking Garage Above

A Group S-2 enclosed parking garage with not more than one story above grade plane and located below a Group S-2 open parking garage shall be classified as a separate and distinct building for the purpose of determining the type of construction where the following conditions are met:
  1. The allowable area of the building shall be such that the sum of the ratios of the actual area divided by the allowable area for each separate occupancy shall not exceed 1.
  2. The Group S-2 enclosed parking garage is of Type I or II construction and is at least equal to the fire-resistance requirements of the Group S-2 open parking garage.
  3. The height and the number of tiers of the Group S-2 open parking garage shall be limited as specified in Table 406.5.4.
  4. The floor assembly separating the Group S-2 enclosed parking garage and Group S-2 open parking garage shall be protected as required for the floor assembly of the Group S-2 enclosed parking garage. Openings between the Group S-2 enclosed parking garage and Group S-2 open parking garage, except exit openings, shall not be required to be protected.
  5. The Group S-2 enclosed parking garage is used exclusively for the parking or storage of private motor vehicles, but shall be permitted to contain an office, waiting room and toilet room having a total area of not more than 1,000 square feet (93 m2) and mechanical equipment rooms associated with the operation of the building.
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510.4 Parking Beneath Group R

Where a maximum one story above grade plane Group S-2 parking garage, enclosed or open, or combination thereof, of Type I construction or open of Type IV construction, with grade entrance, is provided under a building of Group R, the number of stories to be used in determining the minimum type of construction shall be measured from the floor above such a parking area. The floor assembly between the parking garage and the Group R above shall comply with the type of construction required for the parking garage and shall also provide a fire-resistance rating not less than the mixed occupancy separation required in Section 508.4.
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510.5 Group R-1 and R-2 Buildings of Type IIIA Construction

For buildings of Type IIIA construction in Groups R-1 and R-2, the maximum allowable height in Table 504.3 shall be increased by 10 feet (3048 mm) and the maximum allowable number of stories in Table 504.4 shall be increased by one where the first-floor assembly above the basement has a fire-resistance rating of not less than 3 hours and the floor area is subdivided by 2-hour fire-resistancerated fire walls into areas of not more than 3,000 square feet (279 m2).
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510.6 Group R-1 and R-2 Buildings of Type IIA Construction

The height limitation for buildings of Type IIA construction in Groups R-1 and R-2 shall be increased to nine stories and 100 feet (30 480 mm) where the building is separated by not less than 50 feet (15 240 mm) from any other building on the lot and from lot lines, the exits are segregated in an area enclosed by a 2-hour fire-resistance-rated fire wall and the first floor assembly has a fire-resistance rating of not less than 11/2 hours.
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510.7 Open Parking Garage Beneath Groups A, I, B, M and R

Open parking garages constructed under Groups A, I, B, M and R shall not exceed the height and area limitations permitted under Section 406.5. The height and area of the portion of the building above the open parking garage shall not exceed the limitations in Section 503 for the upper occupancy. The height, in both feet and stories, of the portion of the building above the open parking garage shall be measured from grade plane and shall include both the open parking garage and the portion of the building above the parking garage.
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510.7.1 Fire Separation

Fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711 between the parking occupancy and the upper occupancy shall correspond to the required fire-resistance rating prescribed in Table 508.4 for the uses involved. The type of construction shall apply to each occupancy individually, except that structural members, including main bracing within the open parking structure, which is necessary to support the upper occupancy, shall be protected with the more restrictive fire-resistance-rated assemblies of the groups involved as shown in Table 601. Means of egress for the upper occupancy shall conform to Chapter 10 and shall be separated from the parking occupancy by fire barriers having not less than a 2-hour fire-resistance rating as required by Section 707 with self-closing doors complying with Section 716 or horizontal assemblies having not less than a 2-hour fire-resistance rating as required by Section 711, with self-closing doors complying with Section 716. Means of egress from the open parking garage shall comply with Section 406.5.

510.8 Group B or M Buildings With Group S-2 Open Parking Garage Above

Group B or M occupancies located below a Group S-2 open parking garage of a lesser type of construction shall be considered as a separate and distinct building from the Group S-2 open parking garage for the purpose of determining the type of construction where the following conditions are met:
  1. The buildings are separated with a horizontal assembly having a fire-resistance rating of not less than 2 hours.
  2. The occupancies in the building below the horizontal assembly are limited to Groups B and M.
  3. The occupancy above the horizontal assembly is limited to a Group S-2 open parking garage.
  4. The building below the horizontal assembly is of Type IA construction.
    Exception: The building below the horizontal assembly shall be permitted to be of Type IB or II construction, but not less than the type of construction required for the Group S-2 open parking garage above, where the building below is not greater than one story in height above grade plane.
  5. The height and area of the building below the horizontal assembly does not exceed the limits set forth in Section 503.
  6. The height and area of the Group S-2 open parking garage does not exceed the limits set forth in Section 406.5. The height, in both feet and stories, of the Group S-2 open parking garage shall be measured from grade plane and shall include the building below the horizontal assembly.
  7. Exits serving the Group S-2 open parking garage discharge at grade with direct and unobstructed access to a street or public way and are separated from the building below the horizontal assembly by 2-hour fire barriers constructed in accordance with Section 707 or 2-hour horizontal assemblies constructed in accordance with Section 711, or both.
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510.9 Multiple Buildings Above a Horizontal Assembly

Where two or more buildings are provided above the horizontal assembly separating a Group S-2 parking garage or building below from the buildings above in accordance with the special provisions in Section 510.2, 510.3 or 510.8, the buildings above the horizontal assembly shall be regarded as separate and distinct buildings from each other and shall comply with all other provisions of this code as applicable to each separate and distinct building.