CBC · California Building Code

How does construction type affect allowable building height and area?

Construction type (Types I–V) determines the minimum fire‑resistance of structural elements (Table 601/§602.1), and Chapter 5 uses that classification together with occupancy and sprinkler status to read allowable heights from Table 504.3 (§504.3) and allowed floor areas from Table 506.2 and the equations in §506.2; higher fire‑resistance types and sprinkler protection generally permit larger heights and areas.

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Last reviewed: July 5, 2026

What the code requires

The California Building Code ties how tall and how large a building may be to (1) its occupancy, (2) its type of construction (Types I–V, as defined in Chapter 6), and (3) whether the building is protected throughout by an automatic sprinkler system. Limits are set in the Tables called out in Chapter 5 (see §503, §504 and §506) and the construction-type definitions/fire‑resistance requirements are controlled by Table 601 and §602.1. §503.1 explains that height, stories and area limits are applied independently and are based on the type of construction and occupancy.

Requirements in detail

1) Where construction type enters the rules (what Table 601 does)

  • Chapter 6 classifies buildings by construction type and requires building elements to meet the minimum fire‑resistance ratings in Table 601 (see §601.1 and §602.1). Table 601 is the reference that ties a Type (IA, IB, IIA, IIB, IIIA, IIIB, IV, VA, VB, etc.) to the required fire‑resistance ratings for principal structural elements; those ratings are the basis for the more generous height/area allowances given to higher‑rated (less combustible) types.

Note: the uploaded extracts show the scope and purpose of Table 601 (§601.1 / §602.1) but the full printed Table 601 rows were not returned in the file snippets I retrieved; the code text confirms Table 601 is the controlling fire‑resistance table for types of construction.

2) How allowable height is determined

  • The building height and number of stories a building may have are determined from Table 504.3 (and Table 504.4 for stories). §504.1 requires you to pick the limits based on type of construction, occupancy and sprinkler protection. §504.3 directs you to Table 504.3 for the numeric height limits. Where a construction type provides higher fire resistance, Table 504.3 typically allows greater heights; Type I construction in many occupancies is given the largest (often “UL”/unlimited) tabular heights.

  • Sprinkler systems: a building equipped throughout with an approved automatic sprinkler system frequently gets increased height and story allowances (the table rows and footnotes distinguish NS (nonsprinklered) and S (sprinklered) values). See the footnote language in the table and §504.1.

3) How allowable area is determined

  • The allowable floor area per story is taken from Table 506.2 (the tabular allowable area factors) and adjusted using the formulas in §506.2.1 and §506.2.2:

    • For up to two stories: Equation 5‑1, Aa = At + (NS × If)
    • For more than two stories: Equation 5‑2, Aa = [At + (NS × If)] × Sa
    • At = tabular area factor for the building’s construction/occupancy/sprinkler status (from Table 506.2). NS = the tabular nonsprinkler factor from Table 506.2 (used in the formula regardless of whether the building is sprinklered). If = frontage factor per §506.3. Sa = story area multiplier where applicable.

  • Table 506.2 explicitly lists different tabular values for each occupancy and construction type (columns for Type I A/B, Type II A/B, Type III A/B, Type IV variants, Type V A/B) and separate rows for NS versus S (sprinkler) values. A higher fire‑resistance construction type (or the presence of sprinklers) produces larger At values in many occupancies.

Quick decision‑table (how construction type affects the outcome)

Construction-type effect What that means in practice Code reference
Higher fire‑resistance (Type I / IA / IB) → largest allowances Many occupancies show UL or the highest tabular heights/areas for Type I; consult Table 504.3 and Table 506.2 for exact values §504.3; Table 504.3; §506.2; Table 506.2; §602.1
Mid-range (Types II, III, IV) → intermediate allowances Tabular heights/areas drop progressively as construction moves toward more combustible types §504.3; Table 504.3; Table 506.2
Lowest fire‑resistance (Type V) → smallest allowances Type V entries typically have the lowest height/area factors in the tables Table 504.3; Table 506.2; §602.1
Sprinklers (S) increase allowances Table rows/footnotes show S (sprinklered) values are larger than NS values; the equations use NS for the frontage term even if sprinklered §504.1; Table 504.3; Table 506.2; §506.2.1

(For precise numeric height/area values for a given occupancy/construction combination, read Table 504.3 for height and Table 506.2 for At/NS values — both appear in the code extract provided.)

Exceptions & special cases

  • Special industrial occupancies that require large heights/areas for equipment can be exempted from §§504 and 506 limits (§503.1.1).
  • Type I buildings that are already permitted unlimited tabular heights/areas are not subject to the unlimited-area provisions of §507 or other increases intended for lesser types (§503.1.3).
  • Unlimited‑area and other special provisions (for example, certain Group E, movie theaters or mixed unlimited exceptions) are in §507 and §510 and may create exceptions or additional allowances when specific criteria (sprinklers, separation, public way width, etc.) are met. See §504.1.1 and §507 for unlimited-area design guidance.
  • Where multiple occupancies exist, each occupancy’s height/area limits apply to that occupancy per §504.2 and §508 (mixed‑occupancy rules) — the most restrictive rules usually control.

Common mistakes

  • Applying the wrong construction type: the type is defined by Chapter 6 and Table 601’s required fire‑resistance ratings — you must classify the building correctly before reading Tables 504.3/506.2. (§602.1 / Table 601).
  • Forgetting the sprinkler effect: sprinklered (S) values and nonsprinklered (NS) values differ; the formulas use the NS tabular value in the frontage term even if the building is sprinklered — read §506.2 and Table 506.2 carefully.
  • Counting mezzanines or occupiable roofs as extra stories/areas when they are excluded by §505.2 and §503.1.4 rules (mezzanines are part of the story below and occupiable roofs are not included as building area when they meet §503.1.4).
  • Overlooking special provisions that modify limits (e.g., §510 increases/adjustments, open parking garage rules in §406.5.4). Always check Chapter 4/5 cross‑references for your occupancy.

Worked example — movie theater (A‑1) allowable area, concrete numbers

Scenario: Single‑story movie theater (Group A‑1) in Type II‑A construction, building equipped throughout with sprinklers that qualify as S1 (the Table 506.2 sprinkler category). No frontage bonus (If = 0).

Step 1 — Tabular values from Table 506.2 (Table entries returned in the file excerpts):

  • For A‑1, Type II‑A: NS = 15,500 (nonsprinkler tabular value) and S1 = 62,000 (sprinklered tabular value).

Step 2 — Use Equation 5‑1 (single‑story): Aa = At + (NS × If) where If=0. §506.2.1 / Equation 5‑1.

Calculation:

  • At (S1, Type II‑A) = 62,000 sf (from Table 506.2)
  • NS (Type II‑A) = 15,500 sf (Table 506.2)
  • If = 0 (no frontage bonus)

So Aa = 62,000 + (15,500 × 0) = 62,000 square feet allowable area for that single story.

Notes:

  • If you intended more than two stories, you would use Equation 5‑2 and the Sa multiplier in §506.2.2. If you had frontage that generates a frontage bonus, compute If per §506.3 and apply it in the equation.

Related provisions

  • §503 General building height and area limitations (includes occupiable roofs, buildings on same lot).
  • §504 Building height and number of stories; Table 504.3 (allowable heights).
  • §506 Building area; Equations 5‑1 and 5‑2 and Table 506.2 (allowable areas).
  • §601.1 Scope (Chapter 6 / Table 601 controls construction classification).
  • §602.1 Construction classification and reference to Table 601.
  • §505 Mezzanines and equipment platforms (mezzanine counting rules).
  • §507 Unlimited‑area buildings (special unlimited area rules and criteria).
  • §510 Special provisions and height/area increases for special conditions.

Code references

Grounded in the retrieved California Building Code — click a citation to read the verbatim passage:

  • CBC § 903.3.1.1 High relevance — show source text

    Exceptions:

    1. The occupancy located on an occupiable 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 occupiable roof. Emergency voice/alarm communication system notification per Section 907.5.2.2 shall also be provided in the area of the occupiable 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.

    503.1.4.1 Enclosures over occupiable roof areas. Elements or structures enclosing the occupiable roof areas shall not extend more than 48 inches (1220 mm) above the surface of the occupiable roof.

    Exceptions:

    1. Penthouses constructed in accordance with Section 1511.2 and towers, domes, spires and cupolas constructed in accordance with Section 1511.5.

    2. Elements or structures enclosing the occupiable roof areas where the roof deck is located more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access.

    SECTION 504—BUILDING HEIGHT AND NUMBER OF STORIES

    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.

    504.1.1 Unlimited area buildings. The height of unlimited area buildings shall be designed in accordance with Section 507.

    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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    GENERAL BUILDING HEIGHTS AND AREAS

    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.

  • CBC § 1305.2.1.1 High relevance — show source text

    1305.2.1.1 Height formula. The following formulas shall be used in computing the building height value.

    Equation 13-1 Height value, feet = (---------------------------------- [AH] ) – ( EBH - ) × CF 12.5

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    PERFORMANCE COMPLIANCE METHODS

    Equation 13-2 Height value, stories = ( AS – EBS ) × CF

    where:

    AH = Allowable height in feet (mm) from Section 504 of the International Building Code .

    EBH = Existing building height in feet (mm).

    AS = Allowable height in stories from Section 504 of the International Building Code .

    EBS = Existing building height in stories.

    CF = 1 if ( AH ) – ( EBH ) is positive.

    CF = Construction-type factor shown in Table 1305.2.6(2) if ( AH ) – ( EBH ) is negative.

    Note: Where mixed occupancies are separated and individually evaluated as indicated in Section 1305.2, the values AH, AS, EBH and EBS shall be based on the height of the occupancy being evaluated.

    1305.2.2 Building area. The value for building area shall be determined by the formula in Section 1305.2.2.2. Section 506 of the International Building Code and the formula in Section 1305.2.2.1 shall be used to determine the allowable area of the building. Enter the area value and its sign (positive or negative) in Table 1306.1 under Safety Parameter 1305.2.2, Building Area, for fire safety, means of egress and general safety. In determining the area value, the maximum permitted positive value for area is 50 percent of the fire safety score as listed in Table 1306.2, Mandatory Safety Scores. Group I-2 occupancies shall be scored zero.

    1305.2.2.1 Allowable area formula. The following formula shall be used in computing allowable area:

    Equation 13-3 A a = A t + ( NS × I f )

    where:

    A a n= Allowable building area per story (square feet). A t = Tabular allowable area factor (NS, S1, S13R, or SM value, as applicable) in accordance with Table 506.2 of the Inter- national Building Code .

    NS = Tabular allowable area factor in accordance with Table 506.2 of the International Building Code for a nonsprinklered building (regardless of whether the building is sprinklered).

    I f = Area factor increase due to frontage as calculated in accordance with Section 506.3 of the International Building Code .

  • CBC § 5-19 High relevance — show source text

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    GENERAL BUILDING HEIGHTS AND AREAS

    1. 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.
    2. 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 m [2] ) and mechanical equipment rooms associated with the operation of the building.

    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.

    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-resistance-rated fire walls into areas of not more than 3,000 square feet (279 m [2] ).

  • CBC § 503.1 High relevance — show source text

    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.

    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 struc- tural 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. 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. 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 consti- tute 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.

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    GENERAL BUILDING HEIGHTS AND AREAS

    FIGURE 5-1

  • CBC § 5-1 High relevance — show source text

    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. 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 consti- tute 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.

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    GENERAL BUILDING HEIGHTS AND AREAS

    FIGURE 5-1

    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.

    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 Occupiable roofs. A roof level or portion thereof shall not be used as an occupiable roof unless 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 occupiable roofs shall not be included in the building area as regulated by Section 506. An occupiable 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.

  • CBC § 903.2.6. High relevance — show source text

    For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
    h. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
    i. See Sections 407.1.1 and 408.1.2 for specific exceptions to construction type, allowable building areas and allowable heights.
    j. Restraint shall not be permitted in any building except in Group I-3 occupancies constructed for such use (see Section 408.1.2).
    k. Nonambulatory persons shall be limited to the first 2 stories.
    l. Nonambulatory persons shall be limited to the first 5 stories.
    m.Nonambulatory elderly clients are not permitted in buildings of these types of construction. See Sections 435.3.3 and 435.3.4.
    n. 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.
    o. 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 permit-
    ted in addition to the height and story increase provided the height shall not exceed 60 feet and 4 stories.
    p. See Section 436.1 for additional regulations for child-care centers and adult day care.|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.
    a. See Chapters 4 and 5 for specific exceptions to the allowable height in this chapter.
    b. See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies.
    c. New Group H occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5.
    d. The NS value is only for use in evaluation of existing building height in accordance with the_California Existing Building Code_.
    e. New Group I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
    f. New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6 and Section 1103.5 of the_California_
    Fire Code.
    g. For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
    h. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
    i. See Sections 407.1.1 and 408.1.2 for specific exceptions to construction type, allowable building areas and allowable heights.
    _j.

  • CBC § 5-2 High relevance — show source text

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    5 GENERAL BUILDING HEIGHTS AND AREAS

    User notes:

    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.

    ICC code development note: Code change proposals to sections preceded by the designation [F] or [BE] will be considered by a code development committee meeting during the 2024 (Group A) Code Development Cycle. All other code change proposals will be considered by a code development committee meeting during the 2025 (Group B) Code Development Cycle.

    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.

    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 struc- tural 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. For all occupancies, the highest point of the structure/panel shall meet the lower of the two values below: _1.

  • CBC § 510.2 High relevance — show source text

    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 a horizontal assembly contains vertical offsets, the vertical offset shall be constructed as a fire barrier in accordance with Section 707 and shall have a fire-resistance rating of not less than 3 hours.

    2. The building below, including the horizontal assembly and any associated vertical offsets, 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:

    4. The building above the horizontal assembly is not required to be of Type I construction.

    5. The enclosure connects fewer than four stories.

    6. The enclosure opening protectives above the horizontal assembly have a fire protection rating of not less than 1 hour.

    7. Interior exit stairways located within the Type IA building are permitted to be of combustible materials where the following requirements are met: 4.1. The building above the Type IA building is of Type III, IV, or V construction. 4.2. 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.

    8. The building or buildings above the horizontal assembly shall be Group A, B, M, R or S occupancies.

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    GENERAL BUILDING HEIGHTS AND AREAS

    1. 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.
    2. 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.
  • CBC § 5-1 High relevance — show source text

    GENERAL BUILDING HEIGHTS AND AREAS

    FIGURE 5-1

    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.

    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 Occupiable roofs. A roof level or portion thereof shall not be used as an occupiable roof unless 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 occupiable roofs shall not be included in the building area as regulated by Section 506. An occupiable 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 occupiable 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 occupiable roof. Emergency voice/alarm communication system notification per Section 907.5.2.2 shall also be provided in the area of the occupiable 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.

    503.1.4.1 Enclosures over occupiable roof areas. Elements or structures enclosing the occupiable roof areas shall not extend more than 48 inches (1220 mm) above the surface of the occupiable roof.

    Exceptions:

    1. Penthouses constructed in accordance with Section 1511.2 and towers, domes, spires and cupolas constructed in accordance with Section 1511.5.

    2. Elements or structures enclosing the occupiable roof areas where the roof deck is located more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access.

    SECTION 504—BUILDING HEIGHT AND NUMBER OF STORIES

    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.

  • CBC § 406.5.4 High relevance — show source text
    TABLE 406.5.4—OPEN PARKING GARAGES AREA AND HEIGHT Col2 Col3 Col4 Col5
    TYPE OF
    CONSTRUCTION    		 AREA PER TIER
    (square feet)    		 HEIGHT (in tiers) HEIGHT (in tiers) HEIGHT (in tiers)
    TYPE OF
    CONSTRUCTION    		 AREA PER TIER
    (square feet)    		 Ramp access Mechanical access Mechanical access
    TYPE OF
    CONSTRUCTION    		 AREA PER TIER
    (square feet)    		 Ramp access Automatic sprinkler system Automatic sprinkler system
    TYPE OF
    CONSTRUCTION    		 AREA PER TIER
    (square feet)    		 Ramp access No Yes
    IA Unlimited Unlimited Unlimited Unlimited
    IB Unlimited 12 tiers 12 tiers 18 tiers
    IIA 50,000 10 tiers 10 tiers 15 tiers
    IIB 50,000 8 tiers 8 tiers 12 tiers
    IV 50,000 4 tiers 4 tiers 4 tiers
    For SI: 1 square foot = 0.0929 m2. For SI: 1 square foot = 0.0929 m2. For SI: 1 square foot = 0.0929 m2. For SI: 1 square foot = 0.0929 m2. For SI: 1 square foot = 0.0929 m2.

    406.5.4.1 Single use. Where the open parking garage is used exclusively for the parking or storage of private motor vehicles, and the building is without other uses, the area and height shall be permitted to comply with Table 406.5.4, along with increases allowed by Section 406.5.5.

    Exception: The grade-level tier is permitted to contain an office, waiting and toilet rooms having a total combined area of not more than 1,000 square feet (93 m [2] ). Such area need not be separated from the open parking garage.

    In open parking garages having a spiral or sloping floor, the horizontal projection of the structure at any cross section shall not exceed the allowable area per parking tier. In the case of an open parking garage having a continuous spiral floor, each 9 feet 6 inches (2896 mm) of height, or portion thereof, shall be considered under these provisions to be a tier.

    406.5.5 Area and height increases. The allowable area and height of open parking garages shall be increased in accordance with the provisions of this section. Garages with sides open on three-fourths of the building’s perimeter are permitted to be increased by 25 percent in area and one tier in height. Garages with sides open around the entire building’s perimeter are permitted to be increased by 50 percent in area and one tier in height. For a side to be considered open under these provisions, the total area of openings along the side shall be not less than 50 percent of the interior area of the side at each tier and such openings shall be equally distributed along the length of the tier. For purposes of calculating the interior area of the side, the height shall not exceed 7 feet (2134 mm).

  • CBC § 509.1 High relevance — show source text

    Unique consideration is taken for special use areas, such as covered mall buildings, motor-vehicle-related occupancies, special amusement buildings and aircraftrelated occupancies. Special facilities within other occupancies are considered, such as stages and platforms, motion picture projection rooms, children’s play structures and storm shelters. Finally, in order that the overall package of protection features can be easily understood, unique considerations for specific occupancies are also addressed.

    Chapter 5 General Building Heights and Areas.

    Chapter 5 contains the provisions that regulate the minimum type of construction for area limits and height limits based on the occupancy of the building. Height and area increases are permitted based on open frontage for fire department access, separation and the type of sprinkler protection provided (Sections 503 through 506, 510). Provisions include the protection and/or separation of incidental uses (Table 509.1), accessory occupancies (Section 508.2) and mixed uses in the same building (Sections 506.2.2, 508.3, 508.4 and 510). Unlimited area buildings are permitted in certain occupancies when they meet special provisions (Section 507). Live/work units are provided for in Section 508.5.

    Tables 504.3, 504.4 and 506.2 are the keystones in setting thresholds for building size based on the building’s use and the materials with which it is constructed. Respective to each group classification, the greater the fire-resistance rating of structural elements, as represented by the type of construction, the greater the floor area and height allowances. The greater the potential fire hazards indicated as a function of the group, the lesser the height and area allowances for a particular construction type.

    Chapter 6 Types of Construction.

    The interdependence of fire safety considerations can be seen by looking at Tables 601 and 705.5, which show the fire-resistance ratings of the principal structural elements comprising a building in relation to the five classifications for types of construction. Type I construction generally requires the highest fire-resistance ratings for structural elements, whereas Type V construction generally requires the least amount of fire-resistance-rated structural elements. The greater the potential fire hazards indicated as a function of the group, the lesser the height and area allowances for a particular construction type. Section 603 includes a list of combustible elements that can be part of a noncombustible building (Types I and II construction).

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    Chapter 7 Fire and Smoke Protection Features.

    Chapter 7 provisions present the fundamental concepts of fire performance that all buildings are expected to achieve in some form. This chapter identifies the acceptable materials, techniques and methods by which proposed construction can be designed and evaluated against to determine a building’s ability to limit the impact of fire.

    Chapter 7A Materials and Construction Methods for Exterior Wildfire Exposure.

    Requirements for Wildland-Urban Interface Areas are now located in Part 7 of Title 24, California Wildland-Urban Interface Code. The provisions of Part 7, California Wildland-Urban Interface Code, shall apply to buildings and structures located in the wildland-urban interface (WUI) or Fire Hazard Severity Zone.

    Chapter 8 Interior Finishes.

    Chapter 8 contains the performance requirements for controlling fire growth within buildings by restricting interior finish and decorative materials. The provisions of Chapter 8 require materials used as interior finishes and decorations to meet certain flame-spread index or flame-propagation criteria based on the relative fire hazard associated with the occupancy.

    Chapter 9 Fire Protection and Life Safety Systems.

  • CBC § 406.5.4.1 High relevance — show source text

    0929 m2.|

    406.5.4.1 Single use. Where the open parking garage is used exclusively for the parking or storage of private motor vehicles, and the building is without other uses, the area and height shall be permitted to comply with Table 406.5.4, along with increases allowed by Section 406.5.5.

    Exception: The grade-level tier is permitted to contain an office, waiting and toilet rooms having a total combined area of not more than 1,000 square feet (93 m [2] ). Such area need not be separated from the open parking garage.

    In open parking garages having a spiral or sloping floor, the horizontal projection of the structure at any cross section shall not exceed the allowable area per parking tier. In the case of an open parking garage having a continuous spiral floor, each 9 feet 6 inches (2896 mm) of height, or portion thereof, shall be considered under these provisions to be a tier.

    406.5.5 Area and height increases. The allowable area and height of open parking garages shall be increased in accordance with the provisions of this section. Garages with sides open on three-fourths of the building’s perimeter are permitted to be increased by 25 percent in area and one tier in height. Garages with sides open around the entire building’s perimeter are permitted to be increased by 50 percent in area and one tier in height. For a side to be considered open under these provisions, the total area of openings along the side shall be not less than 50 percent of the interior area of the side at each tier and such openings shall be equally distributed along the length of the tier. For purposes of calculating the interior area of the side, the height shall not exceed 7 feet (2134 mm).

    Allowable tier areas in Table 406.5.4 shall be increased for open parking garages constructed to heights less than the table maximum. The gross tier area of the garage shall not exceed that permitted for the higher structure. Not fewer than three sides of each such larger tier shall have continuous horizontal openings not less than 30 inches (762 mm) in clear height extending for not less than 80 percent of the length of the sides. All parts of such larger tier shall be not more than 200 feet (60 960 mm) horizontally from such an opening. In addition, each such opening shall face a street or yard with access to a street with a width of not less than 30 feet (9144 mm) for the full length of the opening, and standpipes shall be provided in each such tier.

    Open parking garages of Type II construction, with all sides open, shall be unlimited in allowable area where the building height does not exceed 75 feet (22 860 mm). For a side to be considered open, the total area of openings along the side shall be not less than 50 percent of the interior area of the side at each tier and such openings shall be equally distributed along the length of the tier. For purposes of calculating the interior area of the side, the height shall not exceed 7 feet (2134 mm). All portions of tiers shall be within 200 feet (60 960 mm) horizontally from such openings or other natural ventilation openings as defined in Section 406.5.2. These openings shall be permitted to be provided in courts with a minimum dimension of 20 feet (6096 mm) for the full width of the openings.

  • CBC § 510.4 High relevance — show source text

    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 m [2] ) and mechanical equipment rooms associated with the operation of the building.

    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.

    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-resistance-rated fire walls into areas of not more than 3,000 square feet (279 m [2] ).

    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-resistancerated fire wall and the first floor assembly has a fire-resistance rating of not less than 1 [1] / 2 hours.

    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.

    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.

  • CBC § 504.1.1 High relevance — show source text

    504.1.1 Unlimited area buildings. The height of unlimited area buildings shall be designed in accordance with Section 507.

    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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    GENERAL BUILDING HEIGHTS AND AREAS

    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 PLANEa, i Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14
    OCCUPANCY
    CLASSIFICATION    		 TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION
    OCCUPANCY
    CLASSIFICATION    		 See Footnotes Type I Type I Type II Type II Type III Type III Type IV Type IV Type IV Type IV Type V Type V
    OCCUPANCY
    CLASSIFICATION    		 See Footnotes 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
    B, F, M, S, U S UL 180 85 75 85 75 270 180 85 85 70 60
    _A,
  • CBC § 803.11 High relevance — show source text

    Occupancy classification also plays a key part in the appropriate protection measures. As such, threshold requirements for fire protection and means of egress systems are based on occupancy classification (see Chapters 9 and 10). Other sections of the code also contain requirements respective to the classification of building groups. For example, Section 706 specifies requirements for fire wall fire-resistance ratings that are tied to the occupancy classification of a building and Section 803.11 contains interior finish requirements that are dependent upon the occupancy classification. The use of the space, rather than the occupancy of the building, is utilized for determining occupant loading (Section 1004) and live loading (Section 1607).

    Chapter 4 Special Detailed Requirements Based on Occupancy and Use.

    Chapter 4 contains the requirements for protecting special uses and occupancies which are supplemental to the remainder of the code. For example, the height and area limitations established in Chapter 5 apply to all special occupancies unless Chapter 4 contains height and area limitations. In this case, the limitations in Chapter 4 supersede those in other sections. An example of this is the height and area limitations for open parking garages given in Section 406.5.4, which supersede the limitations given in Sections 504 and 506.

    In some instances, it may not be necessary to apply the provisions of Chapter 4. For example, if a covered mall building complies with the provisions of the code for Group M, Section 402 does not apply; however, other sections that address a use, process or operation must be applied to that specific occupancy, such as stages and platforms, special amusement buildings and hazardous materials (Sections 410, 411 and 414).

    The chapter includes requirements for buildings and conditions that apply to one or more groups, such as high-rise buildings, underground buildings or atriums. Special uses may also imply specific occupancies and operations, such as for Group H, hazardous materials, and uses with associated combustibility hazards, which are coordinated with the CFC. Unique consideration is taken for special use areas, such as covered mall buildings, motor-vehicle-related occupancies, special amusement buildings and aircraftrelated occupancies. Special facilities within other occupancies are considered, such as stages and platforms, motion picture projection rooms, children’s play structures and storm shelters. Finally, in order that the overall package of protection features can be easily understood, unique considerations for specific occupancies are also addressed.

    Chapter 5 General Building Heights and Areas.

    Chapter 5 contains the provisions that regulate the minimum type of construction for area limits and height limits based on the occupancy of the building. Height and area increases are permitted based on open frontage for fire department access, separation and the type of sprinkler protection provided (Sections 503 through 506, 510). Provisions include the protection and/or separation of incidental uses (Table 509.1), accessory occupancies (Section 508.2) and mixed uses in the same building (Sections 506.2.2, 508.3, 508.4 and 510). Unlimited area buildings are permitted in certain occupancies when they meet special provisions (Section 507). Live/work units are provided for in Section 508.5.

    Tables 504.3, 504.4 and 506.2 are the keystones in setting thresholds for building size based on the building’s use and the materials with which it is constructed. Respective to each group classification, the greater the fire-resistance rating of structural elements, as represented by the type of construction, the greater the floor area and height allowances. The greater the potential fire hazards indicated as a function of the group, the lesser the height and area allowances for a particular construction type.

  • CBC § 506.1.3 Medium relevance — show source text

    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 (A = NS, S1, S13R, S13D or SM, as applicable) IN SQUARE FEETa, b, j
    t    		 Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14
    OCCUPANCY
    CLASSIFICATION    		 SEE FOOTNOTES TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION
    OCCUPANCY
    CLASSIFICATION    		 SEE FOOTNOTES Type I Type I Type II Type II Type III Type III Type IV Type IV Type IV Type IV Type V Type V
    OCCUPANCY
    CLASSIFICATION    		 SEE FOOTNOTES 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
    A-1 S1 UL UL 62,000 34,000 56,000 34,000 180,000 120,000 75,000 60,000 46,000 22,000
    A-1 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
    A-1 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
    A-2 S1 UL UL 62,000 38,000 56,000 38,000 180,000 120,000 75,000 60,000 46,
  • CBC § 903.2 Medium relevance — show source text

    See Chapters 4 and 5 for specific exceptions to the allowable height in this chapter.
    b. See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies.
    c. New Group H occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5.
    d. The NS value is only for use in evaluation of existing building height in accordance with the_California Existing Building Code_.
    e. New Group I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
    f. New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6 and Section 1103.5 of the_California_
    Fire Code.
    g. For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
    h. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
    i. See Sections 407.1.1 and 408.1.2 for specific exceptions to construction type, allowable building areas and allowable heights.
    j. Restraint shall not be permitted in any building except in Group I-3 occupancies constructed for such use (see Section 408.1.2).
    k. Nonambulatory persons shall be limited to the first 2 stories.
    l. Nonambulatory persons shall be limited to the first 5 stories.
    m.Nonambulatory elderly clients are not permitted in buildings of these types of construction. See Sections 435.3.3 and 435.3.4.
    n. 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.
    o. 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 permit-
    ted in addition to the height and story increase provided the height shall not exceed 60 feet and 4 stories.
    p. See Section 436.1 for additional regulations for child-care centers and adult day care.|

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    GENERAL BUILDING HEIGHTS AND AREAS

    SECTION 505—MEZZANINES AND EQUIPMENT PLATFORMS

    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).

  • CBC § 2.1 Medium relevance — show source text

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    Chapter 3 Occupancy Classification and Use.

    Chapter 3 provides for the classification of buildings, structures and parts thereof based on the purpose for which they are used. Section 302 identifies the groups into which all buildings, structures and parts thereof must be classified. Sections 303 through 312 identify the occupancy characteristics of each group classification. In some sections, specific group classifications having requirements in common are collectively organized such that one term applies to all. For example, Groups A-1, A-2, A-3, A-4 and A-5 are individual groups for assembly-type buildings. The general term “Group A,” however, includes each of these individual groups. Other groups include Business (B), Organized Camps (C), Educational (E), Factory (F-1, F-2), High Hazard (H-1, H-2, H-3, H-4, H-5), Institutional (I-2, I-3, I-4), Laboratories (L), Mercantile (M), Residential (R-1, R-2, R-2.1, R-2.2, R-3, R-3.1, R-4), Storage (S-1, S-2) and Utility (U). In some occupancies, the smaller number means a higher hazard, but that is not always the case.

    Defining the use of the buildings is very important as it sets the tone for the remaining chapters of the code. Occupancy works with the height, area and construction type requirements in Chapters 5 and 6, to determine "equivalent risk." The determination of equivalent risk involves three interdependent considerations: (1) the level of fire hazard associated with the specific occupancy of the facility; (2) the reduction of fire hazard based on the fuel load by limiting the floor area and the height of the building; and (3) the level of overall fire resistance provided by the type of construction. The greater the potential fire hazards indicated as a function of the group, the lesser the height and area allowances for a particular construction type.

    Occupancy classification also plays a key part in the appropriate protection measures. As such, threshold requirements for fire protection and means of egress systems are based on occupancy classification (see Chapters 9 and 10). Other sections of the code also contain requirements respective to the classification of building groups. For example, Section 706 specifies requirements for fire wall fire-resistance ratings that are tied to the occupancy classification of a building and Section 803.11 contains interior finish requirements that are dependent upon the occupancy classification. The use of the space, rather than the occupancy of the building, is utilized for determining occupant loading (Section 1004) and live loading (Section 1607).

    Chapter 4 Special Detailed Requirements Based on Occupancy and Use.

    Chapter 4 contains the requirements for protecting special uses and occupancies which are supplemental to the remainder of the code. For example, the height and area limitations established in Chapter 5 apply to all special occupancies unless Chapter 4 contains height and area limitations. In this case, the limitations in Chapter 4 supersede those in other sections. An example of this is the height and area limitations for open parking garages given in Section 406.5.4, which supersede the limitations given in Sections 504 and 506.

Frequently asked questions

How do I decide whether to use the NS or S value in Table 506.2?

The tabular At value you use depends on whether the table row is NS (nonsprinklered) or an S‑category (sprinklered). If your building is equipped throughout with the qualifying automatic sprinkler system, use the appropriate S row for At. Note that the formula still uses the NS tabular value in the frontage term. See §506.2 and Table 506.2.

If I change construction from Type V to Type II, what should I expect?

Expect larger allowable heights and areas in many occupancies — Type II construction requires higher fire‑resistance for principal elements than Type V, and the tables (504.3 and 506.2) reflect larger numeric allowances for the less‑combustible types. Confirm exact numbers in Table 504.3 and Table 506.2 after identifying occupancy and sprinkler status.

Do mezzanines increase my building area or story count?

Mezzanines that comply with §505.2 are considered part of the story below; they do not count as additional stories nor as separate building area for the purposes of Chapters 5 area/story limits (they are, however, counted when determining the fire area).

Where do I find the construction‑type definitions that the tables are based on?

Chapter 6 (see §601 and §602) and Table 601 define construction types and the required fire‑resistance ratings for structural elements — those ratings are what the height/area tables rely on. The code text indicates Table 601 is the controlling fire‑resistance table for types of construction.

Can sprinklering ever make a building unlimited area or height?

Sprinklers increase tabular allowances and may enable unlimited‑area or special exceptions in specific circumstances (see §507 and certain footnotes and special provisions in Chapter 5). Always check the specific occupancy rows and footnotes in Tables 504.3 / 506.2 and §507 conditions.

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