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Chapter 3 — OCCUPANCY CLASSIFICATION AND USE

Section 307

California Building Code (Title 24, Part 2) · 2019 edition · updated 2026-09-12 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

HIGH-HAZARD GROUP H

[F] 307.1 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 414, based on the maximum allowable quantity limits for control areas set forth in Tables 307.1(1) and 307.1(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 section, the require

ments of Section 415 and the California Fire Code . Hazardous materials stored, or used on top of roofs or canopies, shall be classified as outdoor storage or use and shall comply with the California Fire Code .

[F] 307.1.1 Uses other than Group H. An occupancy that stores, uses or handles hazardous materials as described in one or more of the following items shall not be classified as Group H, but shall be classified as the occupancy that it most nearly resembles.

  1. Buildings and structures occupied for the application of flammable finishes, provided that such buildings or areas conform to the requirements of Section 416 and the California Fire Code .

  2. Wholesale and retail sales and storage of flammable and combustible liquids in mercantile occupancies conforming to the California Fire Code .

  3. Closed piping system containing flammable or combustible liquids or gases utilized for the operation of machinery or equipment.

  4. Cleaning establishments that utilize combustible liquid solvents having a flash point of 140°F (60°C) or higher in closed systems employing equipment listed by an approved testing agency,

TABLE 307.1(1) MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA OF HAZARDOUS MATERIALS POSING A PHYSICAL HAZARD a, j, m, n, p

¬

MATERIAL CLASS GROUP WHEN
THE MAXIMUM
ALLOWABLE
QUANTITY IS
EXCEEDED
STORAGEb USE-CLOSED SYSTEMSb USE-OPEN SYSTEMSb
MATERIAL CLASS GROUP WHEN
THE MAXIMUM
ALLOWABLE
QUANTITY IS
EXCEEDED
Solid
pounds
(cubic feet)
Liquid
gallons
(pounds)
Gas cubic
feet at NTP
Solid
pounds
(cubic feet)
Liquid
gallons
(pounds)
Gas cubic
feet at NTP
Solid
pounds
(cubic feet)
Liquid
gallons
(pounds)
Combustible dust NA H-2 See
Note q
NA NA See
Note q
NA NA See
Note q
NA
Combustible fiberq Loose
Baledo
H-3 (100)
(1,000)
NA NA (100)
(1,000)
NA NA (20)
(200)
NA
Combustible liquidc, i II
IIIA
IIIB
H-2 or H-3
H-2 or H-3
NA
NA 120d, e
330d, e
13,200e, f
NA NA 120d
330d
13,200f
NA NA 30d
80d
3,300f
Cryogenic flammable NA H-2 NA 45d NA NA 45d NA NA 10d
Cryogenic inert NA NA NA NA NL NA NA NL NA NA
Cryogenic oxidizing NA H-3 NA 45d NA NA 45d NA NA 10d
Explosives Division 1.1
Division 1.2
Division 1.3
Division 1.4
Division 1.4G
Division 1.5
Division 1.6
H-1
H-1
H-1 or H-2
H-3
H-3
H-1
H-1
1e, g
1e, g
_10_e, g
50e, g
125e, l
1e, g
1e, g
(1)e, g
(1)e, g
(10)e, g
(50)e, g
NA
(1)e, g
NA
NA 0.25g
0.25g
1g
50g
NA
0.25g
NA
(0.25)g
(0.25)g
(1)g
(50)g
NA
(0.25)g
NA
NA 0.25g
0.25g
1g
NA
NA
0.25g
NA
(0.25)g
(0.25)g
(1)g
NA
NA
(0.25)g
NA
Flammable gas Gaseous
Liquefied
H-2 NA NA
(150)d, e
1,000d, e
NA
NA NA
(150)d, e
1,000d, e
NA
NA NA
Flammable liquidc IA
IB and IC
H-2
or H-3
NA 30d, e
120d, e
NA NA 30d
120d
NA NA 10d
30d
Flammable liquid,
combination
(IA, IB, IC)
NA H-2
or H-3
NA 120d, e, h NA NA 120d, h NA NA 30d, h

(continued)

100 2019 CALIFORNIA BUILDING CODE

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

OCCUPANCY CLASSIFICATION AND USE

TABLE 307.1(1)—continued MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA OF HAZARDOUS MATERIALS POSING A PHYSICAL HAZARD a, j, m, n, p

MATERIAL CLASS GROUP WHEN
THE MAXIMUM
ALLOWABLE
QUANTITY IS
EXCEEDED
STORAGEb USE-CLOSED SYSTEMSb USE-OPEN SYSTEMSb
MATERIAL CLASS GROUP WHEN
THE MAXIMUM
ALLOWABLE
QUANTITY IS
EXCEEDED
Solid
pounds
(cubic feet)
Liquid
gallons
(pounds)
Gas cubic
feet at NTP
Solid
pounds
(cubic feet)
Liquid
gallons
(pounds)
Gas cubic
feet at NTP
Solid
pounds
(cubic feet)
Liquid
gallons
(pounds)
Flammable solid NA H-3 125d, e NA NA 125d NA NA 25d NA
Inert gas Gaseous
Liquefied
NA
NA
NA
NA
NA
NA
NL
NL
NA
NA
NA
NA
NL
NL
NA
NA
NA
NA
Organic peroxide UD
I
II
III
IV
V
H-1
H-2
H-3
H-3
NA
NA
1e, g
5d, e
50d, e
125d, e
NL
NL
(1)e, g
(5)d, e
(50)d, e
(125)d, e
NL
NL
NA 0.25g
1d
50d
125d
NL
NL
(0.25)g
(1)d
(50)d
(125)d
NL
NL
NA 0.25g
1d
10d
25d
NL
NL
(0.25)g
(1)d
(10)d
(25)d
NL
NL
Oxidizer 4
3k
2
1
H-1
H-2 or H-3
H-3
NA
1g
10d, e
250d, e
4,000e, f
(1)e, g
(10)d, e
(250)d, e
(4,000)e, f
NA 0.25g
2d
250d
4,000f
(0.25)g
(2)d
(250)d
(4,000)f
NA 0.25g
2d
50d
1,000f
(0.25)g
(2)d
(50)d
(1,000)f
Oxidizing gas Gaseous
Liquefied
H-3 NA NA
(150)d, e
1,500d, e
NA
NA NA
(150)d, e
1,500d, e
NA
NA NA
Pyrophoric NA H-2 4e, g (4)e, g 50e, g 1g (1)g 10e, g 0 0
Unstable (reactive) 4
3
2
1
H-1
H-1 or H-2
H-3
NA
1e, g
5d, e
50d, e
NL
(1)e, g
(5)d, e
(50)d, e
NL
10e, g
50d, e
750d, e
NL
0.25g
1d
50d
NL
(0.25)g
(1)d
(50)d
NL
2e, g
10d, e
750d, e
NL
0.25g
1d
10d
NL
(0.25)g
(1)d
(10)d
NL
Water reactive 3
2
1
H-2
H-3
NA
5d, e
50d, e
NL
(5)d, e
(50)d, e
NL
NA 5d
50d
NL
(5)d
(50)d
NL
NA 1d
10d
NL
(1)d
(10)d
NL

For SI: 1 cubic foot = 0.028 m 3, 1 pound = 0.454 kg, 1 gallon = 3.785 L.

NL = Not Limited; NA = Not Applicable; UD = Unclassified Detonable. a. For use of control areas, see Section 414.2. b. The aggregate quantity in use and storage shall not exceed the quantity listed for storage. c. The quantities of alcoholic beverages in retail and wholesale sales occupancies shall not be limited provided the liquids are packaged in individual containers

not exceeding 1.3 gallons. In retail and wholesale sales occupancies, the quantities of medicines, foodstuffs or consumer products, and cosmetics containing not more than 50 percent by volume of water-miscible liquids with the remainder of the solutions not being flammable, shall not be limited, provided that such materials are packaged in individual containers not exceeding 1.3 gallons. d. [SFM] In other than Group L occupancies, maximum allowable quantities shall be increased 100 percent in buildings equipped throughout with an automatic

ing not more than 50 percent by volume of water-miscible liquids with the remainder of the solutions not being flammable, shall not be limited, provided that such materials are packaged in individual containers not exceeding 1.3 gallons. d. [SFM] In other than Group L occupancies, maximum allowable quantities shall be increased 100 percent in buildings equipped throughout with an automatic

sprinkler system in accordance with Section 903.3.1.1. Where Note e also applies, the increase for both notes shall be applied accumulatively. e. Maximum allowable quantities shall be increased 100 percent when stored in approved storage cabinets, day boxes, gas cabinets, gas rooms or exhausted

enclosures or in listed safety cans in accordance with Section 5003.9.10 of the California Fire Code . Where Note d also applies, the increase for both notes shall be applied accumulatively. f. Quantities shall not be limited in a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1. g. Allowed only in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1. h. Containing not more than the maximum allowable quantity per control area of Class IA, IB or IC flammable liquids. i. The maximum allowable quantity shall not apply to fuel oil storage complying with Section 603.3.2 of the California Fire Code . j. Quantities in parentheses indicate quantity units in parentheses at the head of each column. k. A maximum quantity of 220 pounds of solid or 22 gallons of liquid Class 3 oxidizers is allowed when such materials are necessary for maintenance purposes,

operation or sanitation of equipment when the storage containers and the manner of storage are approved. l. Net weight of the pyrotechnic composition of the fireworks. Where the net weight of the pyrotechnic composition of the fireworks is not known, 25 percent

of the gross weight of the fireworks, including packaging, shall be used. m.For gallons of liquids, divide the amount in pounds by 10 in accordance with Section 5003.1.2 of the California Fire Code . n. For storage and display quantities in Group M and storage quantities in Group S occupancies complying with Section 414.2.5, see Tables 414.2.5(1) and

414.2.5(2). o. Densely packed baled cotton that complies with the packing requirements of ISO 8115 shall not be included in this material class. p. The following shall not be included in determining the maximum allowable quantities:

  1. Liquid or gaseous fuel in fuel tanks on vehicles.
  2. Liquid or gaseous fuel in fuel tanks on motorized equipment operated in accordance with the California Fire Code .
  3. Gaseous fuels in piping systems and fixed appliances regulated by the California Mechanical Code .
  4. Liquid fuels in piping systems and fixed appliances regulated by the California Mechanical Code .
  5. Alcohol-based hand rubs classified as Class I or II liquids in dispensers that are installed in accordance with Sections 5705.5 and 5705.5.1 of the California Fire Code . The location of the alcohol-based hand rub (ABHR) dispensers shall be provided in the construction documents. q. 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.

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

OCCUPANCY CLASSIFICATION AND USE

[F] TABLE 307.1(2) MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA OF HAZARDOUS MATERIALS POSING A HEALTH HAZARD a, c, f, h, i

MATERIAL STORAGEb USE-CLOSED SYSTEMSb USE-OPEN SYSTEMSb
MATERIAL Solid
poundsd, e
Liquid gallons
(pounds)d, e
Gas cubic feet at NTP
(pounds)d
Solid
poundsd
Liquid gallons
(pounds)d
Gas cubic feet at NTP
(pounds)d
Solid
poundsd
Liquid gallons
(pounds)d
Corrosives 5,000 500 Gaseous 810e
Liquefied (150)
5,000 500 Gaseous 810e
Liquefied (150)
1,000 100
Highly Toxic 10 (10) Gaseous 20g
Liquefied (4)g
10 (10) Gaseous 20g
Liquefied (4)g
3 (3)
Toxic 500 (500) Gaseous 810e
Liquefied (150)e
500 (500) Gaseous 810e
Liquefied (150)e
125 (125)

For SI: 1 cubic foot = 0.028 m 3, 1 pound = 0.454 kg, 1 gallon = 3.785 L. a. For use of control areas, see Section 414.2. b. The aggregate quantity in use and storage shall not exceed the quantity listed for storage. c. In retail and wholesale sales occupancies, the quantities of medicines, foodstuffs or consumer products, and cosmetics containing not more than 50 percent by

volume of water-miscible liquids and with the remainder of the solutions not being flammable, shall not be limited, provided that such materials are packaged in individual containers not exceeding 1.3 gallons. d. [SFM] In other than Group L occupancies, maximum allowable quantities shall be increased 100 percent in buildings equipped throughout with an approved

automatic sprinkler system in accordance with Section 903.3.1.1. Where Note e also applies, the increase for both notes shall be applied accumulatively. e. Maximum allowable quantities shall be increased 100 percent where stored in approved storage cabinets, gas cabinets or exhausted enclosures as specified in

the California Fire Code . Where Note d also applies, the increase for both notes shall be applied accumulatively. f. For storage and display quantities in Group M and storage quantities in Group S occupancies complying with Section 414.2.5, see Tables 414.2.5(1) and

414.2.5(2). g. Allowed only where stored in approved exhausted gas cabinets or exhausted enclosures as specified in the California Fire Code . h. Quantities in parentheses indicate quantity units in parentheses at the head of each column. i. For gallons of liquids, divide the amount in pounds by 10 in accordance with Section 5003.1.2 of the California Fire Code .

provided that this occupancy is separated from all other areas of the building by 1-hour fire barriers constructed in accordance with Section 707 or 1hour horizontal assemblies constructed in accordance with Section 711, or both.

  1. Cleaning establishments that utilize a liquid solvent having a flash point at or above 200°F (93°C).

  2. Liquor stores and distributors without bulk storage.

  3. Refrigeration systems.

  4. The storage or utilization of materials for agricultural purposes on the premises.

  5. Stationary storage battery systems installed in accordance with the California Fire Code.

  6. Corrosive personal or household products in their original packaging used in retail display.

  7. Commonly used corrosive building materials.

  8. Buildings and structures occupied for aerosol product storage shall be classified as Group S-1, provided that such buildings conform to the requirements of the California Fire Code .

  9. Display and storage of nonflammable solid and nonflammable or noncombustible liquid hazardous materials in quantities not exceeding the maximum allowable quantity per control area in Group M or S occupancies complying with Section 414.2.5.

  10. The storage of black powder, smokeless propellant and small arms primers in Groups M and R-3 and

special industrial explosive devices in Groups B, F, M and S, provided such storage conforms to the quantity limits and requirements prescribed in the California Fire Code .

  1. Stationary fuel cell power systems installed in accordance with the California Fire Code.

  2. Capacitor energy storage systems in accordance with the California Fire Code.

  3. [SFM] Group L occupancies defined in Section 453.

[F] 307.2 Hazardous materials. Hazardous materials in any quantity shall conform to the requirements of this code, including Section 414, and the California Fire Code .

[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 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

102 2019 CALIFORNIA BUILDING CODE

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

[F] 307.3.1 Occupancies containing explosives not clas- sified 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 H-2 occupancies.

  2. 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 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 H2. 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. Flammable gases. 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 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

OCCUPANCY CLASSIFICATION AND USE

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

[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 listed 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.

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Contents — California Building Code (Title 24, Part 2)
California Building Code (Title 24, Part 2)
  1. Chapter 2 — DEFINITIONS AND ABBREVIATIONS
  2. Appendix G — FLOOD-RESISTANT
  3. Appendix L — EARTHQUAKE RECORDING
  4. Appendix M — TSUNAMI-GENERATED
  5. Chapter 1 — SCOPE AND ADMINISTRATION
  6. Chapter 3 — OCCUPANCY CLASSIFICATION AND USE
  7. Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED
  8. Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS
  9. Chapter 6 — TYPES OF CONSTRUCTION
  10. Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
  11. Chapter 7A — MATERIALS AND CONSTRUCTION
  12. Chapter 8 — INTERIOR FINISHES
  13. Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
  14. Chapter 10 — MEANS OF EGRESS
  15. Chapter 11A — HOUSING ACCESSIBILITY
  16. Chapter 11B — ACCESSIBILITY TO PUBLIC BUILDINGS, PUBLIC ACCOMM…
  17. Chapter 12 — INTERIOR ENVIRONMENT
  18. Chapter 14 — EXTERIOR WALLS
  19. Chapter 15 — ROOF ASSEMBLIES AND ROOFTOP STRUCTURES
  20. Chapter 16 — STRUCTURAL DESIGN
  21. Chapter 16A — STRUCTURAL DESIGN
  22. Chapter 17 — SPECIAL INSPECTIONS AND TESTS
  23. Chapter 18 — SOILS AND FOUNDATIONS
  24. Chapter 19 — CONCRETE
  25. Chapter 20 — ALUMINUM
  26. Chapter 21 — MASONRY
  27. Chapter 22 — STEEL
  28. Chapter 23 — WOOD
  29. Chapter 24 — GLASS AND GLAZING
  30. Chapter 25 — GYPSUM BOARD, GYPSUM PANEL PRODUCTS AND PLASTER
  31. Chapter 26 — PLASTIC
  32. Chapter 27 — ELECTRICAL
  33. Chapter 28 — MECHANICAL SYSTEMS
  34. Chapter 30 — ELEVATORS AND CONVEYING SYSTEMS
  35. Chapter 31 — SPECIAL CONSTRUCTION
  36. Chapter 31B — PUBLIC POOLS
  37. Chapter 31C — RADIATION
  38. Chapter 31D — FOOD ESTABLISHMENTS
  39. Chapter 31F — MARINE OIL TERMINALS
  40. Chapter 32 — ENCROACHMENTS INTO THE PUBLIC RIGHT-OF-WAY
  41. Chapter 33 — SAFEGUARDS DURING CONSTRUCTION
  42. Chapter 35 — REFERENCED STANDARDS
  43. Appendix A — EMPLOYEE QUALIFICATIONS
  44. Appendix B — BOARD OF APPEALS
  45. Appendix C — GROUP U – AGRICULTURAL BUILDINGS
  46. Appendix D — FIRE DISTRICTS
  47. Appendix F — RODENTPROOFING
  48. Appendix H — SIGNS
  49. Appendix I — PATIO COVERS
  50. Appendix J — GRADING
  51. Appendix K — GROUP R-3 AND GROUP R-3.1 OCCUPANCIES
  52. Appendix N — REPLICABLE BUILDINGS
  53. Appendix O — EMERGENCY HOUSING

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