Chapter 66 — UNSTABLE (REACTIVE) MATERIALS
Section 6604
California Fire Code (Title 24, Part 9) · 2022 edition · updated 2026-09-10 · California
CBSC: official editions, supplements and errata
Italicized text is a California amendment to the model code, as printed in the official publication.
6604.1 Indoor storage. Indoor storage of unstable (reactive)¶
materials in amounts exceeding the maximum allowable quantity per control area indicated in Table 5003.1.1(1) shall be in accordance with Sections 5001, 5003, 5004 and this chapter.
In addition, Class 3 and 4 unstable (reactive) detonable materials shall be stored in accordance with the California Building Code requirements for explosives.
6604.1.1 Detached storage. Storage of unstable (reactive) materials shall be in detached buildings where required in Section 5003.8.2.
6604.1.2 Explosion control. Indoor storage rooms, areas and buildings containing Class 3 or 4 unstable (reactive) materials shall be provided with explosion control in accordance with Section 911.
6604.1.3 Liquid-tight floor. In addition to Section 5004.12, floors of storage areas for liquids and solids shall be of liquid-tight construction.
6604.1.4 Storage configuration. Unstable (reactive) materials stored in quantities greater than 500 cubic feet (14 m 3 ) shall be separated into piles, each not larger than 500 cubic feet (14 m 3 ). Aisle width shall be not less than the height of the piles or 4 feet (1219 mm), whichever is greater.
Exception: Materials stored in tanks.
6604.1.5 Location in building. Unstable (reactive) materials shall not be stored in basements.
6604.2 Outdoor storage.¶
Outdoor storage of unstable (reactive) materials in amounts exceeding the maximum allowable quantities per control area indicated in Table 5003.1.1(3) shall be in accordance with Sections 5001, 5003, 5004 and this chapter.
6604.2.1 Distance from storage to exposures Class 4 and 3 (detonable) materials. Outdoor storage of Class 4 or 3 (detonable) unstable (reactive) material shall be in accordance with Table 5604.5.2(2). The number of pounds of material listed in the table shall be the net weight of the material present. Alternatively, the number of pounds of material shall be based on a trinitrotoluene (TNT) equivalent weight.
6604.2.2 Distance from storage to exposures Class 3 (deflagratable) materials. Outdoor storage of deflagratable Class 3 unstable (reactive) materials shall be in accordance with Table 5604.5.2(3). The number of pounds of material listed shall be the net weight of the material present.
6604.2.3 Distance from storage to exposures Class 2 and 1 materials. Outdoor storage of Class 2 or 1 unstable (reactive) materials shall not be located within 20 feet (6096 mm) of buildings not associated with the manufacture or distribution of such materials, lot lines, public streets, public alleys, public ways or means of egress. The minimum required distance shall not apply where fire barriers without openings or penetrations having a minimum fire-resistance rating of 2 hours interrupt the line of sight between the storage and the exposure. The fire barrier shall either be an independent structure or the exterior wall of the building adjacent to the storage area.
6604.2.4 Storage configuration. Piles of unstable (reactive) materials shall not exceed 1,000 cubic feet (28 m 3 ).
6604.2.5 Aisle widths. Aisle widths between piles shall be not less than one-half the height of the pile or 10 feet (3048 mm), whichever is greater.
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