CBC · California Building Code

When is a space classified as Group H (high-hazard)?

Plain English: A room is a Group H (high‑hazard) occupancy when it stores, uses or produces hazardous materials in amounts larger than the code’s maximum allowable quantities (see Tables 307.1(1) and 307.1(2)); certain materials (like explosives) automatically place the space into a specific H subgroup. Consult § 307.1 for the MAQ trigger, § 307.2 for Fire Code coordination, and § 307.3 for detonation/explosives rules.

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Last reviewed: July 5, 2026

What the code requires — plain English

A space becomes a Group H (high‑hazard) occupancy when it is used for manufacturing, processing, generating or storing materials that present a physical or health hazard in quantities greater than the maximum allowable quantities for control areas shown in the code tables; those quantities are the trigger for Group H classification and the hazard is then assigned to one of the H subgroups (H‑1 through H‑5). See § 307.1 for the controlling statement and the reference to the control‑area tables (Tables 307.1(1) and 307.1(2)) that establish the quantity limits.

Additionally, Group H occupancies must be considered together with the California Fire Code where indicated by the CBC (see § 307.2).

If the material itself creates a detonation hazard (explosives, detonable pyrophorics, etc.), the space is classified as H‑1 (see § 307.3 and § 307.3.1 for how certain explosives are assigned to H‑1, H‑2 or H‑3).

Requirements in detail

Key idea (how classification is determined)

  • Determine the hazardous material class/type (physical hazard vs. health hazard, NFPA/transportation/explosives divisions, flammable liquid class, oxidizer type, etc.). § 307.1 requires classification based on the materials present and their quantities relative to the code tables.
  • Compare the actual maximum quantity in the proposed control area to the maximum allowable quantity (MAQ) for that material in Tables 307.1(1) and 307.1(2). If the stored/used quantity exceeds the MAQ, the space is a Group H occupancy. § 307.1 and the table headings identify this test.
  • If the material is an explosive or susceptible to detonation, follow § 307.3 and § 307.3.1 to place the occupancy into H‑1, H‑2 or H‑3 as required by the material/division and how it is used or packaged.

Decision‑relevant dimensions (summary table)

Decision dimension What to check Effect if trigger met Code reference
Material category (physical hazard vs. health hazard) Identify material (flammable liquid/gas, oxidizer, corrosive, toxic, explosives, etc.) Determines which Group H subtype applies (H‑1…H‑5) § 307.1 and Tables 307.1(1)/(2)
Quantity in a control area Compare actual stored/used quantity to the MAQ in Table 307.1(1) or 307.1(2) If quantity > MAQ the control area (and potentially the occupancy) is Group H § 307.1, Table 307.1(1)/(2)
Explosive/pyrophoric materials (Divisions 1.1–1.6, detonable pyrophorics, etc.) Identify explosive Division and how material is used/packaged Division 1.1/1.2/detonable materials → H‑1; specific Division 1.3/1.4 treatment described in § 307.3.1 § 307.3 and § 307.3.1
Items specifically listed as H‑2/H‑3 types (deflagration vs. physical hazard) Match item to lists in the H group descriptions (e.g., Category 1A gases → H‑2; oxidizing gases → H‑3) Determines required subgroup (H‑2, H‑3, etc.) and associated restrictions § 307.3 (and following H group sections)
Code coordination / Fire Code requirements Verify compliance with the California Fire Code for hazardous materials and rooftop storage/uses Fire Code may change allowable storage/use arrangements or impose additional requirements § 307.2 notes compliance with the California Fire Code; see related Fire Code sections referenced by the CBC

Notes:

  • The CBC delegates the quantification trigger to Tables 307.1(1) and 307.1(2) (maximum allowable quantities per control area). Those table entries are the numeric decision points you must look up in the code. § 307.1 and the table captions identify those tables as the MAQ source.

How explosives and similar materials are treated

  • Materials that "pose a detonation hazard" are classified H‑1 (examples and lists are provided in § 307.3). § 307.3 explicitly lists detonable pyrophoric materials and explosives (Divisions 1.1–1.6) as H‑1.
  • There are special rules for explosives not automatically H‑1: § 307.3.1 allows Division 1.3 and certain Division 1.4 situations to be classified in less restrictive H groups (H‑2 or H‑3) based on confinement, configuration and propagation characteristics.

Exceptions & special cases

  • Storage, use and handling of hazardous materials that conform to the exemptions listed in Table 307.1.1 are not counted toward the MAQ and shall not cause classification as Group H; those exempted quantities remain subject to applicable code provisions but do not by themselves trigger Group H. The CBC explicitly identifies these occupancy exemptions.
  • Roof/top‑of‑building storage or use of hazardous materials is treated separately (rooftop storage/use) and must comply with the California Fire Code as noted by the CBC—see § 307.1 for the rooftop-storage cross reference and § 307.2 for code coordination.
  • Multiple hazards: if a space contains materials that fall into more than one H subgroup (for example, both explosive material and highly toxic material), the building must conform to the requirements for each occupancy classification that applies (i.e., comply with the most restrictive applicable H provisions). The CBC provides for multiple hazards (see the H group sections that follow § 307.1).

Common mistakes

  • Assuming any presence of a hazardous material automatically creates a Group H occupancy. The CBC requires comparison to the MAQs in Tables 307.1(1) and 307.1(2) — small, exempted quantities listed in Table 307.1.1 do not automatically trigger Group H (see the exemption language). Always check the MAQ tables.
  • Failing to coordinate with the California Fire Code. The CBC explicitly points users to the Fire Code for hazardous materials matters referenced in § 307.2 and elsewhere; the Fire Code contains many of the material‑specific and procedural regulations that affect classification and compliance.
  • Misclassifying explosives: do not assume all explosive divisions map to the same H subgroup. § 307.3 and § 307.3.1 give specific assignments and exceptions (Division 1.3 and 1.4 have special treatments).
  • Trying to apply a rule-of-thumb MAQ from memory. The MAQs are table driven and material/class dependent; the code tables (Tables 307.1(1)/(2) and the exemptions in Table 307.1.1) are the authoritative source. § 307.1 points to those tables.

Worked example — applying the rule (concrete)

Example A — explosive material (decidable from text):

  • Situation: A laboratory stores packaged Division 1.1 primary explosives and detonable pyrophoric materials for testing; total inventory includes quantities and types that meet the Division 1.1 definition.
  • Code application: Materials that "pose a detonation hazard" are classified as Group H‑1 under § 307.3; therefore the space is Group H‑1. No MAQ table lookup is necessary for the detonation classification — the material hazard itself assigns H‑1. § 307.3.

Example B — flammable liquid (demonstration of the steps; numeric MAQs are in the tables):

  • Situation: A shop stores 500 gallons of a Class I flammable liquid in one control area. (Stored quantity = 500 gal.)
  • Steps to decide:
    1. Identify material and class: Class I flammable liquid — the CBC references combustible/flammable liquid classes for H grouping. § 307.1 and the H group text direct you to the MAQ tables.
    2. Look up the MAQ for Class I liquids in Table 307.1(1) or Table 307.1(2) (depending on whether the hazard is physical or health and on the storage/use condition). The numeric MAQ entries are located in those tables in the code. § 307.1 points you to those tables.
    3. Compare: if the MAQ in the table for your control‑area condition is less than 500 gallons, the control area (and the occupancy, as required) is Group H; if the MAQ is equal or greater than 500 gallons, it does not by itself trigger Group H (other code provisions may still apply).
  • Important: The uploaded code excerpts in this project include the table headings but do not include the full numeric MAQ entries from Tables 307.1(1) and 307.1(2). You must consult those tables in the CBC (or the enforcing agency) to get the actual numeric thresholds before concluding classification. § 307.1 identifies those tables as the MAQ source.

Related provisions (quick list)

  • § 307.1 — High‑hazard Group H general requirement and pointer to Tables 307.1(1) and 307.1(2) (MAQs).
  • § 307.2 — Cross‑reference / coordination with the California Fire Code (check the Fire Code for many hazardous‑materials provisions).
  • § 307.3 — Group H‑1 (detonation hazards) and § 307.3.1 — special rules for explosives not classified as H‑1.
  • Table 307.1(1) and Table 307.1(2) — Maximum allowable quantities per control area (MAQs) that determine when Group H classification is required. § 307.1 points to these tables.
  • Section 414 — Hazardous materials control areas and reporting requirements that apply to Group H occupancies and exemptions (see Section 414 for control‑area construction and MAQ percentage rules).
  • Section 415 — Special Group H construction, fire‑protection and alarm requirements that apply once an occupancy is classified as Group H.

Code references

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

  • CBC § 203.6.5 High relevance — show source text

    Organic peroxides, Class I

    Oxidizers, Class 3, that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103 kPa)

    Pyrophoric liquids, solids and gases, nondetonable

    Unstable (reactive) materials, Class 3, nondetonable

    Water-reactive materials, Class 3

    203.6.5 High-hazard Group H-3. Buildings and structures containing materials that readily support combustion or that pose a physical hazard shall be classified as Group H-3. Such materials shall include, but not be limited to, the following:

    Class I, II or IIIA flammable or combustible liquids that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103.4 kPa) or less

    Combustible fibers, other than densely packed baled cotton, where manufactured, generated or used in such a manner that the concentration and conditions create a fire or explosion hazard based on information prepared in accordance with Section 414.1.3 of the California Building Code

    Consumer fireworks, 1.4G (Class C, Common)

    Cryogenic fluids, oxidizing

    Category 1B flammable gases having a burning velocity of 3.9 inches per second (99 mm/s) or less

    Flammable solids

    Organic peroxides, Class II and III

    Oxidizers, Class 2

    Oxidizers, Class 3, that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103 kPa) or less

    Oxidizing gases

    Unstable (reactive) materials, Class 2

    Water-reactive materials, Class 2

    203.6.6 High-hazard Group H-4. Buildings and structures containing materials that are health hazards shall be classified as Group H-4. Such materials shall include, but not be limited to, the following:

    Corrosives

    Highly toxic materials

    Toxic materials

    203.6.7 High-hazard Group H-5. Semiconductor fabrication facilities and comparable research and development areas in which hazardous production materials (HPM) are used and the aggregate quantity of materials is in excess of those specified in Tables 5003.1.1(1) and 5003.1.1(2) shall be classified as Group H-5. Such facilities and areas shall be designed and constructed in accordance with Section 415.11 of the California Building Code .

    203.6.8 Multiple hazards. Buildings and structures containing a material or materials representing hazards that are classified in one or more of Groups H-1, H-2, H-3 and H-4 shall conform to the code requirements for each of the occupancies so classified.

    [BG] 203.7 Institutional Group I. Institutional Group I occupancy includes, among others, the use of a building or structure, or a portion thereof, in which care or supervision is provided to persons who are or are incapable of self-preservation without physical assistance or in which persons are detained for penal or correctional purposes or in which the liberty of the occupants is restricted. Institutional occupancies shall be classified as Group I-2, I-3 or I-4. Restraint shall not be permitted in any building except in Group I-2 occupancies constructed for such use in accordance with Section 407.1.1 of the California Building Code and Group I-3 occupancies constructed for such use, in accordance with Section 408.1.2 of the California Building Code.

  • CBC § 307.3 High relevance — show source text

    [F] 307.3 High-hazard Group H-1. Buildings and structures containing materials that pose a detonation hazard shall be classified as Group H-1. Such materials shall include, but not be limited to, the following:

    Detonable pyrophoric materials

    Explosives:

    Division 1.1

    Division 1.2

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    Division 1.3

    Division 1.4

    Division 1.5

    Division 1.6

    Organic peroxides, unclassified detonable

    Oxidizers, Class 4

    Unstable (reactive) materials, Class 3 detonable and Class 4

    [F] 307.3.1 Occupancies containing explosives not classified as H-1. The following occupancies containing explosive materials shall be classified as follows:

    1. Division 1.3 explosive materials that are used and maintained in a form where either confinement or configuration will not elevate the hazard from a mass fire to mass explosion hazard shall be allowed in Group H-2 occupancies.
    2. Division 1.4 explosive materials shall be allowed in Group H-3 occupancies.
    3. Articles, including articles packaged for shipment, that are not regulated as a Division 1.4 explosive under Bureau of Alcohol, Tobacco, Firearms and Explosives regulations, or unpackaged articles used in process operations that do not propagate a detonation or deflagration between articles shall be allowed in Group H-3 occupancies.

    [F] 307.4 High-hazard Group H-2. Buildings and structures containing materials that pose a deflagration hazard or a hazard from accelerated burning shall be classified as Group H-2. Such materials shall include, but not be limited to, the following:

    Class I, II or IIIA flammable or combustible liquids that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103.4 kPa).

    Combustible dusts where manufactured, generated or used in such a manner that the concentration and conditions create a fire or explosion hazard based on information prepared in accordance with Section 414.1.3.

    Cryogenic fluids, flammable.

    Category 1A flammable gases.

    Category 1B flammable gases having a burning velocity greater than 3.9 inches per second (10 cm/s).

    Organic peroxides, Class I.

    Oxidizers, Class 3, that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103 kPa).

    Pyrophoric liquids, solids and gases, nondetonable.

    Unstable (reactive) materials, Class 3, nondetonable.

    Water-reactive materials, Class 3.

    [F] 307.5 High-hazard Group H-3. Buildings and structures containing materials that readily support combustion or that pose a physical hazard shall be classified as Group H-3. Such materials shall include, but not be limited to, the following:

    Class I, II or IIIA flammable or combustible liquids that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103.4 kPa) or less

  • CBC § 2-43 High relevance — show source text

    Furniture

    Hemp products

    Jute products

    Laundries

    Leather products

    Lithium-ion batteries

    Machinery

    Metals

    Millwork (sash and door)

    Motion picture and television production studio Sound Stages, Approved Production Facilities and production locations (without live audiences)

    Motion pictures and television filming (without spectators)

    Musical instruments

    Optical goods

    Paper mills or products

    Photographic film

    Plastic products

    Printing or publishing

    Recreational vehicles

    Refuse incineration

    Shoes

    Soaps and detergents

    Textiles

    Tobacco

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    DEFINITIONS

    Trailers

    Upholstering

    Vehicles powered by lithium-ion or lithium metal batteries

    Water/sewer treatment facilities

    Wood; distillation

    Woodworking (cabinet)

    [BG] 203.5.1.1 Aircraft manufacturing facilities. Aircraft manufacturing facilities shall comply with Section 412.6 of the Cali- fornia Building Code .

    [BG] 203.5.2 Low-hazard factory industrial, Group F-2. Factory industrial uses that involve the fabrication or manufacturing of noncombustible materials that during finishing, packing or processing does not involve a significant fire hazard shall be classified as Group F-2 occupancies and shall include, but not be limited to, the following:

    Beverages: up to and including 20-percent alcohol content

    Brick and masonry

    Ceramic products

    Foundries

    Glass products

    Gypsum

    Ice

    Metal products (fabrication and assembly)

    203.6 High-hazard Group H. High-hazard Group H occupancy includes, among others, the use of a building or structure, or a portion thereof, that involves the manufacturing, processing, generation or storage of materials that constitute a physical or health hazard in quantities in excess of those allowed in control areas complying with Section 5003.8.3, based on the maximum allowable quantity limits for control areas set forth in Tables 5003.1.1(1) and 5003.1.1(2). Hazardous occupancies are classified in Groups H-1, H-2, H-3, H-4 and H-5 and shall be in accordance with this code and the requirements of Section 415 of the California Building Code . Hazardous materials stored or used on top of roofs or canopies shall be classified as rooftop storage or use and shall comply with this code.

    203.6.1. Occupancy exemptions. Storage, use and handling of hazardous materials in accordance with Table 307.1.1 of the Cali- fornia Building Code shall not be counted as contributing to maximum allowable quantities and shall not cause classification of an occupancy to be Group H. Such storage, use and handling shall comply with applicable provisions of this code.

    203.6.2 Hazardous materials. Hazardous materials in any quantity shall conform to the requirements of this code and Section 414 of the California Building Code .

    203.6.3 High-hazard Group H-1. Buildings and structures containing materials that pose a detonation hazard shall be classified as Group H-1. Such materials shall include, but not be limited to, the following:

    Detonable pyrophoric materials

    Explosives:

    Division 1.1

    Division 1.2

    Division 1.3

    Division 1.4

    Division 1.5

    Division 1.6

  • CBC § 103.4 High relevance — show source text

    Class I, II or IIIA flammable or combustible liquids that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103.4 kPa).

    Combustible dusts where manufactured, generated or used in such a manner that the concentration and conditions create a fire or explosion hazard based on information prepared in accordance with Section 414.1.3.

    Cryogenic fluids, flammable.

    Category 1A flammable gases.

    Category 1B flammable gases having a burning velocity greater than 3.9 inches per second (10 cm/s).

    Organic peroxides, Class I.

    Oxidizers, Class 3, that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103 kPa).

    Pyrophoric liquids, solids and gases, nondetonable.

    Unstable (reactive) materials, Class 3, nondetonable.

    Water-reactive materials, Class 3.

    [F] 307.5 High-hazard Group H-3. Buildings and structures containing materials that readily support combustion or that pose a physical hazard shall be classified as Group H-3. Such materials shall include, but not be limited to, the following:

    Class I, II or IIIA flammable or combustible liquids that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103.4 kPa) or less

    Combustible fibers, other than densely packed baled cotton, where manufactured, generated or used in such a manner that the concentration and conditions create a fire or explosion hazard based on information prepared in accordance with Section 414.1.3

    Consumer fireworks, 1.4G (Class C, Common)

    Cryogenic fluids, oxidizing

    Category 1B flammable gases having a burning velocity of 3.9 inches per second (10 cm/s) or less.

    Flammable solids

    Organic peroxides, Class II and III

    Oxidizers, Class 2

    Oxidizers, Class 3, that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103 kPa) or less

    Oxidizing gases

    Unstable (reactive) materials, Class 2

    Water-reactive materials, Class 2

    [F] 307.6 High-hazard Group H-4. Buildings and structures containing materials that are health hazards shall be classified as Group H-4. Such materials shall include, but not be limited to, the following:

    Corrosives

    Highly toxic materials

    Toxic materials

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    OCCUPANCY CLASSIFICATION AND USE

    [F] 307.7 High-hazard Group H-5. Semiconductor fabrication facilities and comparable research and development areas in which hazardous production materials (HPM) are used and the aggregate quantity of materials is in excess of those specified in Tables 307.1(1) and 307.1(2) shall be classified as Group H-5. Such facilities and areas shall be designed and constructed in accordance with Section 415.11.

  • CBC § 1.4 High relevance — show source text

    Consumer fireworks, 1.4G (Class C, Common)

    Cryogenic fluids, oxidizing

    Category 1B flammable gases having a burning velocity of 3.9 inches per second (10 cm/s) or less.

    Flammable solids

    Organic peroxides, Class II and III

    Oxidizers, Class 2

    Oxidizers, Class 3, that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103 kPa) or less

    Oxidizing gases

    Unstable (reactive) materials, Class 2

    Water-reactive materials, Class 2

    [F] 307.6 High-hazard Group H-4. Buildings and structures containing materials that are health hazards shall be classified as Group H-4. Such materials shall include, but not be limited to, the following:

    Corrosives

    Highly toxic materials

    Toxic materials

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    [F] 307.7 High-hazard Group H-5. Semiconductor fabrication facilities and comparable research and development areas in which hazardous production materials (HPM) are used and the aggregate quantity of materials is in excess of those specified in Tables 307.1(1) and 307.1(2) shall be classified as Group H-5. Such facilities and areas shall be designed and constructed in accordance with Section 415.11.

    [F] 307.8 Multiple hazards. Buildings and structures containing a material or materials representing hazards that are classified in one or more of Groups H-1, H-2, H-3 and H-4 shall conform to the code requirements for each of the occupancies so classified.

    SECTION 308—INSTITUTIONAL GROUP I

    308.1 Institutional Group I. Institutional Group I occupancy includes, among others, the use of a building or structure, or a portion thereof, in which care or supervision is provided to persons who are or are incapable of self-preservation without physical assistance or in which persons are detained for penal or correctional purposes or in which the liberty of the occupants is restricted. Institutional occupancies shall be classified as Group I-2, I-3 or I-4. Restraint shall not be permitted in any building except in Group I-2 occupancies constructed for such use in accordance with Section 407.1.1 and Group I-3 occupancies constructed for such use in accordance with Section 408.1.2.

    Where occupancies house both ambulatory and nonambulatory persons, the more restrictive requirements shall apply.

    308.2 Institutional Group I-1. Not used. (See Group R-2.1 Section 310.1.)

    308.3 Institutional Group I-2. Institutional Group I-2 occupancy shall include buildings and structures used for medical care on a 24hour basis for more than five persons who are incapable of self-preservation or classified as nonambulatory or bedridden. This group shall include, but not be limited to, the following:

    Foster care facilities

    Detoxification facilities

    Hospitals

    Nursing homes

    Psychiatric hospitals

  • CBC § 203.6.1. High relevance — show source text

    Hazardous occupancies are classified in Groups H-1, H-2, H-3, H-4 and H-5 and shall be in accordance with this code and the requirements of Section 415 of the California Building Code . Hazardous materials stored or used on top of roofs or canopies shall be classified as rooftop storage or use and shall comply with this code.

    203.6.1. Occupancy exemptions. Storage, use and handling of hazardous materials in accordance with Table 307.1.1 of the Cali- fornia Building Code shall not be counted as contributing to maximum allowable quantities and shall not cause classification of an occupancy to be Group H. Such storage, use and handling shall comply with applicable provisions of this code.

    203.6.2 Hazardous materials. Hazardous materials in any quantity shall conform to the requirements of this code and Section 414 of the California Building Code .

    203.6.3 High-hazard Group H-1. Buildings and structures containing materials that pose a detonation hazard shall be classified as Group H-1. Such materials shall include, but not be limited to, the following:

    Detonable pyrophoric materials

    Explosives:

    Division 1.1

    Division 1.2

    Division 1.3

    Division 1.4

    Division 1.5

    Division 1.6

    Organic peroxides, unclassified detonable

    Oxidizers, Class 4

    Unstable (reactive) materials, Class 3 detonable and Class 4

    203.6.3.1 Occupancies containing explosives not classified as H-1. The following occupancies containing explosive materials shall be classified as follows:

    1. Division 1.3 explosive materials that are used and maintained in a form where either confinement or configuration will not elevate the hazard from a mass fire to mass explosion hazard shall be allowed in Group H-2 occupancies.
    2. Division 1.4 explosive materials shall be allowed in Group H-3 occupancies.
    3. Articles, including articles packaged for shipment, that are not regulated as a Division 1.4 explosive under Bureau of Alcohol, Tobacco, Firearms and Explosives regulations, or unpackaged articles used in process operations that do not propagate a detonation or deflagration between articles shall be allowed in Group H-3 occupancies.

    203.6.4 High-hazard Group H-2. Buildings and structures containing materials that pose a deflagration hazard or a hazard from accelerated burning shall be classified as Group H-2. Such materials shall include, but not be limited to, the following:

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    DEFINITIONS

    Class I, II or IIIA flammable or combustible liquids that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103.4 kPa)

    Combustible dusts where manufactured, generated or used in such a manner that the concentration and conditions create a fire or explosion hazard based on information prepared in accordance with Section 414.1.3 of the California Building Code.

    Cryogenic fluids, flammable

    Category 1A flammable gases

    Category 1B flammable gases having a burning velocity greater than 3.9 inches per second (99 mm/s)

    Organic peroxides, Class I

  • CBC § 203.1 Medium relevance — show source text

    [BG] YARD. An open space, other than a court, unobstructed from the ground to the sky, except where specifically provided by the California Building Code, on the lot on which a building is situated.

    ZONE. A defined area within the protected premises. A zone can define an area from which a signal can be received, an area to which a signal can be sent or an area in which a form of control can be executed.

    ZONE, NOTIFICATION. An area within a building or facility covered by notification appliances which are activated simultaneously.

    SECTION 203—OCCUPANCY CLASSIFICATION AND USE

    [BG] 203.1 Occupancy classification. Occupancy classification is the formal designation of the primary purpose of the building, structure or portion thereof. Structures shall be classified into one or more of the occupancy groups specified in this section based on the nature of the hazards and risks to building occupants generally associated with the intended purpose of the building or structure. An area, room or space that is intended to be occupied at different times for different purposes shall comply with all applicable requirements associated with such potential multipurpose. Structures containing multiple occupancy groups shall comply with Section 508 of the California Building Code . Where a structure is proposed for a purpose that is not specified in this section, such structure shall be classified in the occupancy it most nearly resembles based on the fire safety and relative hazard. Occupiable roofs shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard, and shall comply with Section 503.1.4 of the California Building Code .

    1. Assembly: Groups A-1, A-2, A-3, A-4 and A-5.

    2. Business: Group B.

    3. Educational: Group E.

    4. Factory and Industrial: Groups F-1 and F-2.

    5. High Hazard: Groups H-1, H-2, H-3, H-4 and H-5.

    6. Institutional: Groups I-1, I-2, I-3 and I-4.

    7. Mercantile: Group M.

    8. Residential: Groups R-1, R-2, R-3 and R-4.

    9. Storage: Groups S-1 and S-2.

    10. Utility and Miscellaneous: Group U.

    [BG] 203.1.1 Use designation. Occupancy groups contain subordinate uses having similar hazards and risks to building occupants. Uses include, but are not limited to, those functional designations specified within the occupancy group descriptions in Section 203.1. Certain uses require specific limitations and controls in accordance with the provisions of this code and Chapter 4 of the California Building Code .

    [BG] 203.2 Assembly Group A. Assembly Group A occupancy includes, among others, the use of a building or structure, or a portion thereof, for the gathering of persons for purposes such as civic, social or religious functions; recreation, food or drink consumption or awaiting transportation or Motion Picture and Television Production Studio Sound Stages, Approved Production Facilities and produc- tion locations. Any building or structure or portion thereof used or intended to be used for the showing of motion pictures when an admission fee is charged and when such building or structure is open to the public and has a capacity of 10 or more persons.

    [BG] 203.2.1 Small buildings and tenant spaces. A building or tenant space used for assembly purposes with an occupant load of less than 50 persons shall be classified as a Group B occupancy.

  • CBC § 301.1 Medium relevance — show source text

    ICC code development note: Code change proposals to sections preceded by the designation [F] will be considered by the IFC 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 301—SCOPE

    301.1 General. The provisions of this chapter shall control the classification of all buildings and structures as to occupancy and use. Different classifications of occupancy and use represent varying levels of hazard and risk to building occupants and adjacent properties.

    SECTION 302—OCCUPANCY CLASSIFICATION AND USE DESIGNATION

    302.1 Occupancy classification. Occupancy classification is the formal designation of the primary purpose of the building, structure or portion thereof. Structures shall be classified into one or more of the occupancy groups specified in this section based on the nature of the hazards and risks to building occupants generally associated with the intended purpose of the building or structure. An area, room or space that is intended to be occupied at different times for different purposes shall comply with all applicable requirements associated with such potential multipurpose. Structures containing multiple occupancy groups shall comply with Section 508. Where a structure is proposed for a purpose that is not specified in this section, such structure shall be classified in the occupancy it most nearly resembles based on the fire safety and relative hazard. Occupiable roofs shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard, and shall comply with Section 503.1.4.

    1. Assembly (see Section 303): Groups A-1, A-2, A-3, A-4 and A-5.
    2. Business (see Section 304): Group B. 3. [SFM] Organized Camps (see Section 450): Group C. 4. Educational (see Section 305): Group E. 5. Factory and Industrial (see Section 306): Groups F-1 and F-2. 6. High Hazard (see Section 307): Groups H-1, H-2, H-3, H-4 and H-5. 7. Institutional (see Section 308): Groups I-2, I-3 and I-4. 8. [SFM] Laboratory (see Section 202): Group B, unless classified as Group L (see Section 453) or Group H (see Section 307). 9. [SFM] Laboratory Suites (see Section 453): Group L. 10. Mercantile (see Section 309): Group M. 11 . Residential (see Section 310): Groups R-1, R-2, R-2.1, R-3, R-3.1 and R-4. 12 . Storage (see Section 311): Groups S-1 and S-2. 13 . Utility and Miscellaneous (see Section 312): Group U. 14. [SFM] Existing buildings housing existing protective social care homes or facilities established prior to 1972 (see California Fire Code Chapter 11 and California Existing Building Code).

    302.1.1 Reserved

    302.1.2 Reserved

    302.1.3 Pharmacies; veterinary facilities; barbering, cosmetology or electrolysis establishments; and acupuncture offices. See Chapter 12.

  • CBC § 3-5 Medium relevance — show source text

    304 Business Group B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

    305 Educational Group E . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

    306 Factory Group F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

    307 High-Hazard Group H . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

    308 Institutional Group I . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

    309 Mercantile Group M. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

    310 Residential Group R. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15

    311 Storage Group S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

    312 Utility and Miscellaneous Group U . . . . . . . . . . . . . . 3-18

    313 Laboratories Group L [SFM]. . . . . . . . . . . . . . . . . . . . . . .3-19

    314 Organized Camps Group C [SFM]. . . . . . . . . . . . . . . . . .3-19

    CHAPTER 4 SPECIAL DETAILED REQUIREMENTS

    BASED ON OCCUPANCY AND USE . . . . . . . . . . . . . . . . . . . .4-1

    401 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

    402 Covered Mall and Open Mall Buildings . . . . . . . . . . . . 4-5

    403 High-Rise Buildings and Group I-2 Occupancies Having Occupied Floors Located More Than 75 Feet above the Lowest Level of

    Fire Department Vehicle Access . . . . . . . . . . . . . . . 4-9

    404 Atriums. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

    405 Underground Buildings . . . . . . . . . . . . . . . . . . . . . . . . 4-13

    406 Motor-Vehicle-Related Occupancies. . . . . . . . . . . . . 4-15

    407 Group I-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19

    408 Group I-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24

  • CBC § 903.2.5 Medium relevance — show source text

    903.2.5

    Ventilation 414.3, 415.9.1.7, 415.11.1.6, 415.11.1.8.1, 415.11.3.2, 415.11.6.8, 415.11.7.4, 415.11.8, 415.11.11, 1202.6 Weather protection 414.6.1 Hazardous Occupancy (Group H), (see Hazardous Materials) 307, 414, 415 Alarms and detection 415.11.2, 415.11.4, 415.11.6.9, 415.11.8, 415.3, 415.5, 907.2.5, 908.1, 908.2 Area 503, 505, 506, 507, 508 Dispersing 414.5, 414.6, 415.6 Gas detection systems 415.11.7 Group provisions H-1 (detonation) 307.3, 415.6.2, 415.7, 415.6.4.1, 415.7.1 H-2 (deflagration) 307.4, 415.8, 415.9 H-3 (physical hazard) 415.10, 307.5, 415.8 H-4 (health hazard) 307.6, 415.10 H-5 (semiconductor) 307.7, 415.11 Height 415.7, 415.8.1, 415.9.1.1, 426.1.1, 503, 504, 505, 506 Incidental uses 509

    Interior finishes 416.2.1, 416.3.1, Table 803.13, 804 Live load Table 1607.1

    Location on property 414.6.1.2, 415.6 Low hazard 306.3, 311.3 Means of egress Corridors 415.11.2 One means of egress Table 1006.3.4(1), Table 1006.3.4(2) Panic hardware 1006.2.2.2, 1006.2.2.3, 1006.2.2.4, 1010.2.8 Stairway, exit access 1019 Travel distance 1006.3, 1006.2.1, Table 1017.2

    Mixed occupancies 508.3, 508.4 Accessory 508.2 Moderate hazard 306.2, 311.2 Multiple hazards 306.2, 311.2 Occupancy exceptions 307.1 Plumbing fixtures Chapter 29 Risk category Table 1604.5 Separation from other occupancies 415.6.1, 508.1, 508.2.4, 508.3.3, 508.4 Smoke and heat removal 910.2 Special provisions based on materials Combustible liquids Table 307.1(1), 307.4, 307.5, 414.2.5, 414.5.3,

    415.9.2

    Corrosives 307.6, Table 414.2.5.1, 414.3, 415.10.3, Table 415.11.1.1 Explosives 307.3, 307.3.1, Table 415.6.5

  • CBC § 1-33 Medium relevance — show source text

    112 Service Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33

    113 Means of Appeals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33

    114 Violations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-34

    115 Stop Work Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-34

    CHAPTER 2 DEFINITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

    201 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

    202 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

    CHAPTER 3 OCCUPANCY CLASSIFICATION AND USE . . . . .3-1

    301 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

    302 Occupancy Classification and Use Designation . . . . 3-3

    303 Assembly Group A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

    304 Business Group B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

    305 Educational Group E . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

    306 Factory Group F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

    307 High-Hazard Group H . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

    308 Institutional Group I . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

    309 Mercantile Group M. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

    310 Residential Group R. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15

    311 Storage Group S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

    312 Utility and Miscellaneous Group U . . . . . . . . . . . . . . 3-18

    313 Laboratories Group L [SFM]. . . . . . . . . . . . . . . . . . . . . . .3-19

  • CBC § 2506.2 Medium relevance — show source text

    Vertical and horizontal assemblies

    2504

    Wallboard Table 2506.2, 2508.2, 2508.2.1, 2508.4, 2510.5.2.1 Water-resistant backing board 2506.2, 2509.2

    Habitable Space 1208 Handrails 1014 Alternating tread devices 1011.14 Assembly aisles 1030.16 Construction 1014.5, 1014.6, 1014.7 Extensions 1014.7 Glazing 2407 Graspability 1014.4 Guards 1015.3 Height 1014.2 Loads 1607.9

    Location 1014.1, 1014.8, 1014.9,

    1014.10

    Ramps 1012.8 Stairs 1011.11

    Hardboard 1403.3.2, 2303.1.7 Hardware (see Doors and Locks and Latching) Hardwood

    Fastening 2304.10 Quality 2303.3 Veneer 1403.3.2 Hazardous Materials 307, 414, 415 Compliance with California Fire Code 307.2

    Control areas 414.2

    Explosion control 414.5.1, Table 414.5.1, 415.11.6.5, 426.1.4 Mercantile occupancies 309.2 Reporting 414.1.3 Sprinkler protection Table 414.2.5.1, Table 414.2.5.2, 415.4, 415.11.12,

    903.2.5

    Ventilation 414.3, 415.9.1.7, 415.11.1.6, 415.11.1.8.1, 415.11.3.2, 415.11.6.8, 415.11.7.4, 415.11.8, 415.11.11, 1202.6 Weather protection 414.6.1 Hazardous Occupancy (Group H), (see Hazardous Materials) 307, 414, 415 Alarms and detection 415.11.2, 415.11.4, 415.11.6.9, 415.11.8, 415.3, 415.5, 907.2.5, 908.1, 908.2 Area 503, 505, 506, 507, 508 Dispersing 414.5, 414.6, 415.6 Gas detection systems 415.11.7 Group provisions H-1 (detonation) 307.3, 415.6.2, 415.7, 415.6.4.1, 415.7.1 H-2 (deflagration) 307.4, 415.8, 415.9 H-3 (physical hazard) 415.10, 307.5, 415.8 H-4 (health hazard) 307.6, 415.10 H-5 (semiconductor) 307.7, 415.11 Height 415.7, 415.8.1, 415.9.1.1, 426.1.1, 503, 504, 505, 506 Incidental uses 509

  • CBC § 203.1.1 Medium relevance — show source text
    1. Business: Group B.
    2. Educational: Group E.
    3. Factory and Industrial: Groups F-1 and F-2.
    4. High Hazard: Groups H-1, H-2, H-3, H-4 and H-5.
    5. Institutional: Groups I-1, I-2, I-3 and I-4.
    6. Mercantile: Group M.
    7. Residential: Groups R-1, R-2, R-3 and R-4.
    8. Storage: Groups S-1 and S-2.
    9. Utility and Miscellaneous: Group U.

    [BG] 203.1.1 Use designation. Occupancy groups contain subordinate uses having similar hazards and risks to building occupants. Uses include, but are not limited to, those functional designations specified within the occupancy group descriptions in Section 203.1. Certain uses require specific limitations and controls in accordance with the provisions of this code and Chapter 4 of the California Building Code .

    [BG] 203.2 Assembly Group A. Assembly Group A occupancy includes, among others, the use of a building or structure, or a portion thereof, for the gathering of persons for purposes such as civic, social or religious functions; recreation, food or drink consumption or awaiting transportation or Motion Picture and Television Production Studio Sound Stages, Approved Production Facilities and produc- tion locations. Any building or structure or portion thereof used or intended to be used for the showing of motion pictures when an admission fee is charged and when such building or structure is open to the public and has a capacity of 10 or more persons.

    [BG] 203.2.1 Small buildings and tenant spaces. A building or tenant space used for assembly purposes with an occupant load of less than 50 persons shall be classified as a Group B occupancy.

    [BG] 203.2.2 Small assembly spaces. The following rooms and spaces shall not be classified as Assembly occupancies:

    1. A room or space used for assembly purposes with an occupant load of less than 50 persons and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy.
    2. A room or space used for assembly purposes that is less than 750 square feet (70 m [2] ) in area and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy.

    [BG] 203.2.3 Associated with Group E occupancies. A room or space used for assembly purposes that is associated with a Group E occupancy is not considered a separate occupancy.

    [BG] 203.2.4 Accessory to places of religious worship. Accessory religious educational rooms and religious auditoriums with occupant loads of less than 100 per room or space are not considered separate occupancies.

    [BG] 203.2.5 Special amusement areas. Special amusement areas shall comply with Section 411 of the California Building Code

    [BG] 203.2.6 Assembly Group A-1. Group A-1 occupancy includes assembly uses, usually with fixed seating, intended for the production and viewing of the performing arts or motion pictures, including but not limited to:

    Motion picture and television production studio Sound Stages, Approved Production Facilities and production locations. (With live audiences.)

    Motion picture theaters

    Symphony and concert halls

    2-40 2025 CALIFORNIA FIRE CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    DEFINITIONS

    Television and radio studios admitting an audience

    Theaters

Frequently asked questions

Does any quantity of a hazardous chemical automatically make a space Group H?

No. The space becomes Group H only when the quantity present in a control area exceeds the maximum allowable quantity listed in Tables 307.1(1) or 307.1(2), or when the material itself is an H‑1 detonable hazard as identified in § 307.3. § 307.1 and the table captions are the controlling references.

Where do I find the numeric thresholds (MAQs) for deciding Group H?

Numeric MAQs are in Tables 307.1(1) and 307.1(2) of the CBC. § 307.1 directs you to those tables; consult them directly in the code to perform the comparison.

If I have a small quantity that is exempt in Table 307.1.1, do I still need to follow other code sections?

Exempted quantities listed in Table 307.1.1 are not counted toward the MAQ for Group H classification, but the storage/use must still comply with other applicable code provisions. The CBC explicitly states these occupancy exemptions.

How are explosives treated differently than other hazardous materials?

Explosives and other detonation hazards are assigned to Group H‑1 per § 307.3. § 307.3.1 then provides criteria where some explosives (Divisions 1.3 or 1.4) may be allowed in H‑2 or H‑3 based on configuration and hazard potential.

Do I need to check the California Fire Code too?

Yes. The CBC specifically points to the California Fire Code for hazardous‑materials matters (see § 307.2). The Fire Code contains important material‑specific rules and operational requirements that affect classification and compliance.

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