Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

Section 414 — HAZARDOUS MATERIALS

2025 California Building Code (Title 24, Part 2) · 2025 edition · updated 2026-07-29 · California

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

[F] 414.1 General. Buildings and structures occupied for the manufacturing, processing, dispensing, use or storage of hazardous materials shall comply with Sections 414.1 through 414.6.

Exception: Exemptions listed in Table 307.1.1 shall not be required to comply with Section 414.

[F] 414.1.1 Other provisions. Buildings and structures with an occupancy in Group H shall comply with this section and the applicable provisions of Section 415 and the California Fire Code. See Section 453 for Group L occupancies.

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SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

[F] 414.1.2 Materials. The safe design of hazardous material occupancies is material dependent. Individual material requirements are found in Sections 307 and 415, the California Mechanical Cod e and the California Fire Code.

[F] 414.1.2.1 Aerosol products, aerosol cooking spray products and plastic aerosol 3 products. Level 2 and 3 aerosol products, aerosol cooking spray products and plastic aerosol 3 products shall be stored and displayed in accordance with the California Fire Code . See Section 311.2 and the California Fire Code for occupancy group requirements.

[F] 414.1.3 Information required. A report shall be submitted to the building official identifying the maximum expected quantities of hazardous materials to be stored, used in a closed system and used in an open system, and subdivided to separately address hazardous material classification categories based on Tables 307.1(1) and 307.1(2). The methods of protection from such hazards, including but not limited to control areas, fire protection systems and Group H occupancies shall be indicated in the report and on the construction documents. The opinion and report shall be prepared by a qualified person, firm or corporation approved by the building official and provided without charge to the enforcing agency.

For buildings and structures with an occupancy in Group H, separate floor plans shall be submitted identifying the locations of anticipated contents and processes so as to reflect the nature of each occupied portion of every building and structure.

[F] 414.2 Control areas. Control areas shall comply with Sections 414.2.1 through 414.2.5 and the California Fire Code .

[F] 414.2.1 Construction requirements. Control areas shall be separated from each other by fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both.

[F] 414.2.2 Percentage of maximum allowable quantities. The percentage of maximum allowable quantities of hazardous materials per control area permitted at each floor level within a building shall be in accordance with Table 414.2.2.

[F] TABLE 414.2.2—DESIGN AND NUMBER OF CONTROL AREAS

STORY	STORY	PERCENTAGE OF THE MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREAa	NUMBER OF CONTROL AREAS PER STORY	FIRE-RESISTANCE RATING FOR FIRE BARRIERS IN HOURSb
Above grade plane	Higher than 9	5	1	2
Above grade plane	7−9	5	2	2
Above grade plane	6	12.5	2	2
Above grade plane	5	12.5	2	2
Above grade plane	4	12.5	2	2
Above grade plane	3	50	2	1
Above grade plane	2	75	3	1
Above grade plane	1	100	4	1
Below grade plane	1	75	3	1
Below grade plane	2	50	2	1
Below grade plane	Lower than 2	Not Allowed	Not Allowed	Not Allowed
a. Percentages shall be of the maximum allowable quantity per control area shown in Tables 307.1(1) and 307.1(2), with all increases allowed in the notes to those tables. b. Separation shall include fire barriers and horizontal assemblies as necessary to provide separation from other portions of the building.

[F] 414.2.3 Number. The maximum number of control areas within a building shall be in accordance with Table 414.2.2. For the purposes of determining the number of control areas within a building, each portion of a building separated by one or more fire walls complying with Section 706 shall be considered a separate building.

[F] 414.2.4 Fire-resistance rating requirements. The required fire-resistance rating for fire barriers shall be in accordance with Table 414.2.2. The floor assembly of the control area and the construction supporting the floor of the control area shall have a fireresistance rating of not less than 2 hours.

Exception: The floor assembly of the control area and the construction supporting the floor of the control area are allowed to be 1-hour fire-resistance-rated in buildings of Types IIA, IIIA, IV and VA construction, provided that both of the following conditions exist:

The building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
The building is three or fewer stories above grade plane.

[F] 414.2.5 Hazardous material in Group M display and storage areas and in Group S storage areas. Hazardous materials located in Group M and Group S occupancies shall be in accordance with Sections 414.2.5.1 through 414.2.5.4.

[F] 414.2.5.1 Nonflammable solids and nonflammable and noncombustible liquids. The aggregate quantity of nonflammable solid and nonflammable or noncombustible liquid hazardous materials permitted within a single control area of a Group M display and storage area, a Group S storage area or an outdoor control area is permitted to exceed the maximum allowable quantities per control area specified in Tables 307.1(1) and 307.1(2) without classifying the building or use as a Group H occupancy, provided that the materials are displayed and stored in accordance with the California Fire Code and quantities do not exceed the maximum allowable specified in Table 414.2.5.1.

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SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

[F] TABLE 414.2.5.1—MAXIMUM ALLOWABLE QUANTITY PER INDOOR AND OUTDOOR CONTROL AREA IN GROUP M
AND S OCCUPANCIES OF NONFLAMMABLE SOLIDS AND NONFLAMMABLE AND NONCOMBUSTIBLE LIQUIDSd, e, f

CONDITION	CONDITION	MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA	MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA
Materiala	Class	Solids (pounds)	Liquids (gallons)
A. Health-hazard materials—nonflammable and noncombustible solids and liquids
1. Corrosivesb, c	Not Applicable	9,750	975
2. Highly toxics	Not Applicable	20b, c	2b, c
3. Toxicsb, c	Not Applicable	1,000k	100
B. Physical-hazard materials—nonflammable and noncombustible solids and liquids
1. Oxidizersb, c	4	Not Allowed	Not Allowed
1. Oxidizersb, c	3	1500g	150
1. Oxidizersb, c	2	2,250h	225
1. Oxidizersb, c	1	18,000i, j	1,800i, j
2. Unstable (reactives)b, c	4	Not Allowed	Not Allowed
2. Unstable (reactives)b, c	3	550	55
2. Unstable (reactives)b, c	2	1,150	115
2. Unstable (reactives)b, c	1	Not Limited	Not Limited
3. Water reactives	3b, c	550	55
3. Water reactives	2b, c	1,150	115
3. Water reactives	1	Not Limited	Not Limited

For SI: 1 pound = 0.454 kg, 1 gallon = 3.785 L.
a. Hazard categories are as specified in the_California Fire Code_.
b. Maximum allowable quantities shall be increased 100 percent in buildings that are sprinklered in accordance with Section 903.3.1.1. Where Note c also applies, the increase
for both notes shall be applied accumulatively.
c. Maximum allowable quantities shall be increased 100 percent where stored in approved storage cabinets, in accordance with the_California Fire Code_. Where Note b also
applies, the increase for both notes shall be applied accumulatively.
d. See Table 414.2.2 for design and number of control areas.
e. Allowable quantities for other hazardous material categories shall be in accordance with Section 307.
f. Maximum quantities shall be increased 100 percent in outdoor control areas.
g. Maximum amounts shall be increased to 2,250 pounds where individual packages are in the original sealed containers from the manufacturer or packager and do not exceed
10 pounds each.
h. Maximum amounts shall be increased to 4,500 pounds where individual packages are in the original sealed containers from the manufacturer or packager and do not exceed
10 pounds each.
i. The permitted quantities shall not be limited in a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
j. Quantities are unlimited in an outdoor control area.
k. Maximum allowable quantities of consumer products shall be increased to 10,000 pounds where individual packages are in the original, sealed containers from the manufac-
turer and the toxic classification is exclusively based on the LC threshold and no other hazardous materials classifications apply.

[F] 414.2.5.2 Flammable and combustible liquids. In Group M occupancy wholesale and retail sales uses, indoor storage of flammable and combustible liquids shall not exceed the maximum allowable quantities per control area as indicated in Table 414.2.5.2, provided that the materials are displayed and stored in accordance with the California Fire Code .

[F] TABLE 414.2.5.2—MAXIMUM ALLOWABLE QUANTITY OF FLAMMABLE AND
COMBUSTIBLE LIQUIDS IN WHOLESALE AND RETAIL SALES OCCUPANCIES PER CONTROL AREAa

TYPE OF LIQUID	MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA (gallons)	MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA (gallons)	MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA (gallons)
TYPE OF LIQUID	Sprinklered in accordance with Note b densities and arrangements	Sprinklered in accordance with Tables 5704.3.6.3(4) through 5704.3.6.3(8) and *5704.3.7.5.1 of theCalifornia Fire Code***	Nonsprinklered
Class IA	60	60	30
Class IB, IC, II and IIIA	7,500c	15,000c	1,600
Class IIIB	Unlimited	Unlimited	13,200

For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m2, 1 gallon = 3.785 L, 1 gallon per minute per square foot = 40.75 L/min/m2.
a. Control areas shall be separated from each other by not less than a 1-hour fire barrier wall.
b. To be considered as sprinklered, a building shall be equipped throughout with an approved automatic sprinkler system with a design providing minimum densities as follows:
1. For uncartoned commodities on shelves 6 feet or less in height where the ceiling height does not exceed 18 feet, quantities are those permitted with a minimum sprin-
kler design density of Ordinary Hazard Group 2.
2. For cartoned, palletized or racked commodities where storage is 4 feet 6 inches or less in height and where the ceiling height does not exceed 18 feet, quantities are
those permitted with a minimum sprinkler design density of 0.21 gallon per minute per square foot over the most remote 1,500-square-foot area.
c. Where wholesale and retail sales or storage areas exceed 50,000 square feet in area, the maximum allowable quantities are allowed to be increased by 2 percent for each
1,000 square feet of area in excess of 50,000 square feet, up to not more than 100 percent of the table amounts. A control area separation is not required. The cumulative
amounts, including amounts attained by having an additional control area, shall not exceed 30,000 gallons.

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SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

[F] 414.2.5.3 Aerosol products, aerosol cooking spray products or plastic aerosol 3 products. The maximum quantity of aerosol products, aerosol cooking spray products or plastic aerosol 3 products in Group M occupancy retail display areas, storage areas adjacent to retail display areas and retail storage areas shall be in accordance with the California Fire Code .

[F] 414.2.5.4 Flammable gas. The aggregate quantity of Category 1B flammable gas having a burning velocity of 3.9 inches per second (10 cm/s) or less stored and displayed within a single control area of a Group M occupancy or stored in a single control area of a Group S occupancy is allowed to exceed the maximum allowable quantities per control area specified in Table 307.1(1) without classifying the building or use as a Group H occupancy, provided that the materials are stored and displayed in accordance with the California Fire Code and quantities do not exceed the amounts specified in Table 414.2.5.4.

occupancy or stored in a single control area of a Group S occupancy is allowed to exceed the maximum allowable quantities per control area specified in Table 307.1(1) without classifying the building or use as a Group H occupancy, provided that the materials are stored and displayed in accordance with the California Fire Code and quantities do not exceed the amounts specified in Table 414.2.5.4.

[F] TABLE 414.2.5.4—MAXIMUM ALLOWABLE QUANTITY OF LOW BURNING VELOCITY
CATEGORY 1B FLAMMABLE GAS IN GROUP M AND S OCCUPANCIES PER CONTROL AREAa

CATEGORY 1B (Low BV)d	MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA	MAXIMUM ALLOWABLE QUANTITY PER CONTROL AREA
CATEGORY 1B (Low BV)d	Sprinkleredb	Nonsprinklered
Gaseous	390,000 cu ft	195,000 cu ft
Liquefied	40,000 lbc	20,000 lb
For SI: 1 pound = 0.454 kg, 1 square foot = 0.0929 m2, 1 cubic foot = 0.028 m3, 1 inch per second = 2.54 cm/s. a. Control areas shall be separated from each other by not less than a 1-hour fire barrier. b. The building shall be equipped throughout with an approved automatic sprinkler system with a minimum sprinkler design density of Ordinary Hazard Group 2 in the area where flammable gases are stored or displayed. c. Where storage areas exceed 50,000 square feet in area, the maximum allowable quantities area is allowed to be increased by 2 percent for each 1,000 square feet of area in excess of 50,000 square feet, up to not more than 100 percent of the table amounts. Separation of control areas is not required. The aggregate amount shall not exceed 80,000 pounds. d._ Low Burning Velocity_(Low BV) Category 1B flammable gas has a burning velocity of 3.9 in/s or less.

[F] 414.3 Ventilation. Rooms, areas or spaces in which explosive, corrosive, combustible, flammable or highly toxic dusts, mists, fumes, vapors or gases are or have the potential to be emitted due to the processing, use, handling or storage of materials shall be mechanically ventilated where required by this code, the California Fire Code or the California Mechanical Code .

Emissions generated at workstations shall be confined to the area in which they are generated as specified in the California Fire Code and the California Mechanical Code .

[F] 414.4 Hazardous material systems. Systems involving hazardous materials shall be suitable for the intended application. Controls shall be designed to prevent materials from entering or leaving process or reaction systems at other than the intended time, rate or path. Automatic controls, where provided, shall be designed to be fail safe.

[F] 414.5 Inside storage, dispensing , handling and use. The inside storage, dispensing and use of hazardous materials shall be in accordance with Sections 414.5.1 through 414.5.3 of this code and the California Fire Code .

[F] 414.5.1 Explosion control. Explosion control shall be provided in accordance with the California Fire Code as required by Table 414.5.1 where quantities of hazardous materials specified in that table exceed the maximum allowable quantities in Table 307.1(1) or where a structure, room or space is occupied for purposes involving explosion hazards as required by Section 415 or the California Fire Code .

[F] TABLE 414.5.1—EXPLOSION CONTROL REQUIREMENTSa, h

MATERIAL	CLASS	EXPLOSION CONTROL METHODS	EXPLOSION CONTROL METHODS
MATERIAL	CLASS	Barricade construction	Explosion (deflagration) venting or explosion (deflagration) prevention systemsb
HAZARD CATEGORY
Combustible dustsc	—	Not Required	Required
Cryogenic flammables	—	Not Required	Required
Explosives	Division 1.1	Required	Not Required
Explosives	Division 1.2	Required	Not Required
Explosives	Division 1.3	Not Required	Required
Explosives	Division 1.4j	Not Required	Required
Explosives	Division 1.5	Required	Not Required
Explosives	Division 1.6	Required	Not Required
Flammable gas	Gaseous	Not Required	Requiredk
Flammable gas	Liquefied	Not Required	Requiredk
Flammable liquid	IAd	Not Required	Required
Flammable liquid	IBe	Not Required	Required
Organic peroxides	U	Required	Not Permitted
Organic peroxides	I	Required	Not Permitted

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SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

[F] TABLE 414.5.1—EXPLOSION CONTROL REQUIREMENTSa, h—continued

MATERIAL	CLASS	EXPLOSION CONTROL METHODS	EXPLOSION CONTROL METHODS
MATERIAL	CLASS	Barricade construction	Explosion (deflagration) venting or explosion (deflagration) prevention systemsb
Oxidizer liquids and solids	4	Required	Not Permitted
Pyrophoric gas	—	Not Required	Required
Unstable (reactive)	4	Required	Not Permitted
Unstable (reactive)	3 Detonable	Required	Not Permitted
Unstable (reactive)	3 Nondetonable	Not Required	Required
Water-reactive liquids and solids	3	Not Required	Required
Water-reactive liquids and solids	2g	Not Required	Required
SPECIAL USES
Acetylene generator rooms	—	Not Required	Required
Electrochemical energy storage systemi	—	Not Required	Required
Energy storage systemi	—	Not Required	Required
Grain processing	—	Not Required	Required
Liquefied petroleum gas-distri- bution facilities	—	Not Required	Required
Where explosion hazards existf	Detonation	Required	Not Permitted
Where explosion hazards existf	Deflagration	Not Required	Required
a. See Section 414.1.3. b. See the_California Fire Code_. c. 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 104.2.2 of the_California Fire Code_. See definition of "Combustible dust" in Chapter 2. d. Storage or use. e. In open use or dispensing. f. Rooms containing dispensing and use of hazardous materials where an explosive environment can occur because of the characteristics or nature of the hazardous materials or as a result of the dispensing or use process. g. A method of explosion control shall be provided where Class 2 water-reactive materials can form potentially explosive mixtures. h. Explosion venting is not required for Group H-5 fabrication areas complying with Section 415.11.1 and the_California Fire Code_. i. Where explosion control is required in Section 1207 of the_California Fire Code_. j. Does not apply to consumer fireworks, Division 1.4G. k. Not required for Category 1B Flammable Gases having a burning velocity not exceeding 3.9 inches per second (10 cm/s).

[F] 414.5.2 Emergency or standby power. Where required by the California Fire Code or this code, mechanical ventilation, treatment systems, temperature control, alarm, detection or other electrically operated systems shall be provided with emergency or standby power in accordance with Section 2702. For storage and use areas for highly toxic or toxic materials, see Sections 6004.2.2.8 and 6004.3.4.2 of the California Fire Code .

[F] 414.5.2.1 Exempt applications. Emergency or standby power is not required for the mechanical ventilation systems provided for any of the following:

Storage of Class IB and IC flammable and combustible liquids in closed containers not exceeding 6.5 gallons (25 L) capacity.
Storage of Class 1 and 2 oxidizers.
Storage of Class II, III, IV and V organic peroxides.
Storage of asphyxiant, irritant and radioactive gases.

[F] 414.5.2.2 Fail-safe engineered systems. Standby power for mechanical ventilation, treatment systems and temperature control systems shall not be required where an approved fail-safe engineered system is installed.

[F] 414.5.3 Spill control, drainage and containment. Rooms, buildings or areas occupied for the storage of solid and liquid hazardous materials shall be provided with a means to control spillage and to contain or drain off spillage and fire protection water discharged in the storage area where required in the California Fire Code . The methods of spill control shall be in accordance with the California Fire Code .

414.5.4 Hazardous material handling. The handling of hazardous materials shall be in accordance with California Fire Code Section 5003.

[F] 414.6 Outdoor storage, dispensing and use. The outdoor storage, dispensing and use of hazardous materials shall be in accordance with the California Fire Code .

[F] 414.6.1 Weather protection. Where weather protection is provided for sheltering outdoor hazardous material storage or use areas, such areas shall be considered outdoor storage or use where the weather protection structure complies with Sections 414.6.1.1 through 414.6.1.3.

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SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

[F] 414.6.1.1 Walls. Walls shall not obstruct more than one side of the structure.

Exception: Walls shall be permitted to obstruct portions of multiple sides of the structure, provided that the obstructed area is not greater than 25 percent of the structure’s perimeter.

[F] 414.6.1.2 Separation distance. The distance from the structure to buildings, lot lines, public ways or means of egress to a public way shall be not less than the distance required for an outside hazardous material storage or use area without weather protection.

[F] 414.6.1.3 Noncombustible construction. The overhead structure shall be of approved noncombustible construction with a maximum area of 1,500 square feet (140 m [2] ).

Exception: The maximum area is permitted to be increased as provided by Section 506.

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