Section 911 — California Fire Code (Title 24, Part 9)

911.1 General. Explosion control shall be provided in the¶

following locations:

Where a structure, room or space is occupied for purposes involving explosion hazards as identified in Table 911.1.
Where quantities of hazardous materials specified in Table 911.1 exceed the maximum allowable quantities in Table 5003.1.1(1).

Such areas shall be provided with explosion (deflagration) venting, explosion (deflagration) prevention systems or barricades in accordance with this section and NFPA 69, or NFPA 495 as applicable. Deflagration venting shall not be utilized as a means to protect buildings from detonation hazards.

TABLE 911.1 EXPLOSION CONTROL REQUIREMENTS ^f

MATERIAL	CLASS	EXPLOSION CONTROL METHODS
MATERIAL	CLASS	Barricade construction	Explosion (deflagration) venting or explosion (deflagration) prevention systems
Hazard Category	Hazard Category	Hazard Category	Hazard Category
Combustible dustsa	—	Not required	Required
Cryogenic fluids	Flammable	Not required	Required
Explosives	Division 1.1 Division 1.2 Division 1.3 Division 1.4 Division 1.5 Division 1.6	Required Required Not required Not required Required Required	Not required Not required Required Required Not required Not required
Flammable gas	Gaseous Liquefied	Not required Not required	Required Required
Flammable liquids	IAb IBc	Not required Not required	Required Required
Organic peroxides	Unclassified detonable I	Required Required	Not permitted Not permitted
Oxidizer liquids and solids	4	Required	Not permitted
Pyrophoric	Gases	Not required	Required
Unstable (reactive)	4 3 detonable 3 nondetonable	Required Required Not required	Not permitted Not permitted Required
Water-reactive liquids and solids	3 2e	Not required Not required	Required Required
Special Uses	Special Uses	Special Uses	Special Uses
Acetylene generator rooms	—	Not required	Required
Grain processing	—	Not required	Required
Liquefied petroleum gas distribution facilities	—	Not required	Required
Where explosion hazards existd	Detonation Deflagration	Required Not required	Not permitted Required

a. Combustible dusts that are generated during manufacturing or processing. See definition of “Combustible dust” in Chapter 2. b. Storage or use. c. In open use or dispensing. d. 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. e. A method of explosion control shall be provided where Class 2 water-reactive materials can form potentially explosive mixtures. f. Explosion venting is not required for Group H-5 Fabrication Areas complying with Chapter 27 and the California Building Code .

212 2019 CALIFORNIA FIRE CODE

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100735044

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911.2 Required deflagration venting. Areas that are¶

required to be provided with deflagration venting shall comply with the following:

Walls, ceilings and roofs exposing surrounding areas shall be designed to resist a minimum internal pressure of 100 pounds per square foot (psf) (4788 Pa). The minimum internal design pressure shall be not less than five times the maximum internal relief pressure specified in Item 5 of this section.
Deflagration venting shall be provided only in exterior walls and roofs.

Exception: Where sufficient exterior wall and roof venting cannot be provided because of inadequate exterior wall or roof area, deflagration venting shall be allowed by specially designed shafts vented to the exterior of the building.

Deflagration venting shall be designed to prevent unacceptable structural damage. Where relieving a deflagration, vent closures shall not produce projectiles of sufficient velocity and mass to cause life threatening injuries to the occupants or other persons on the property or adjacent public ways.
The aggregate clear area of vents and venting devices shall be governed by the pressure resistance of the construction assemblies specified in Item 1 of this section and the maximum internal pressure allowed by Item 5 of this section.
Vents shall be designed to withstand loads in accordance with the California Building Code . Vents shall consist of any one or any combination of the following to relieve at a maximum internal pressure of 20 pounds per square foot (958 Pa), but not less than the loads required by the California Building Code :

5.1. Exterior walls designed to release outward.

5.2. Hatch covers.

5.3. Outward swinging doors.

5.4. Roofs designed to uplift.

5.5. Venting devices listed for the purpose.

Vents designed to release from the exterior walls or roofs of the building when venting a deflagration shall discharge directly to the exterior of the building where an unoccupied space not less than 50 feet (15 240 mm) in width is provided between the exterior walls of the building and the lot line.

Exception: Vents complying with Item 7 of this section.

Vents designed to remain attached to the building when venting a deflagration shall be so located that the discharge opening shall be not less than 10 feet (3048 mm) vertically from window openings and exits in the building and 20 feet (6096 mm) horizontally from exits in the building, from window openings and exits in adjacent buildings on the same lot and from the lot line.
Discharge from vents shall not be into the interior of the building.

FIRE PROTECTION AND LIFE SAFETY SYSTEMS

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911.3 Explosion prevention systems. Explosion prevention¶

systems shall be of an approved type and installed in accordance with the provisions of this code and NFPA 69.

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911.4 Barricades. Barricades shall be designed and installed¶

in accordance with NFPA 495.

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