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Chapter 66 — UNSTABLE (REACTIVE) MATERIALS

Section 6604 — STORAGE

2025 California Fire Code (Title 24, Part 9) · 2025 edition · updated 2026-07-29 · California

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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▸ Contents — 2025 California Fire Code (Title 24, Part 9)
2025 California Fire Code (Title 24, Part 9)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — GENERAL REQUIREMENTS
  4. Chapter 4 — EMERGENCY PLANNING AND PREPAREDNESS
  5. Chapter 5 — FIRE SERVICE FEATURES
  6. Chapter 6 — BUILDING SERVICES AND SYSTEMS
  7. Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
  8. Chapter 8 — INTERIOR FINISH, DECORATIVE MATERIALS AND FURNISHI…
  9. Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
  10. Chapter 10 — MEANS OF EGRESS
  11. Chapter 11 — CONSTRUCTION REQUIREMENTS FOR EXISTING BUILDINGS
  12. Chapter 12 — ENERGY SYSTEMS
  13. Chapter 20 — AVIATION FACILITIES
  14. Chapter 21 — DRY CLEANING
  15. Chapter 22 — COMBUSTIBLE DUST-PRODUCING OPERATIONS
  16. Chapter 23 — MOTOR FUEL-DISPENSING FACILITIES AND REPAIR GARAGES
  17. Chapter 24 — FLAMMABLE FINISHES
  18. Chapter 25 — FRUIT AND CROP RIPENING
  19. Chapter 26 — FUMIGATION AND INSECTICIDAL FOGGING
  20. Chapter 27 — SEMICONDUCTOR FABRICATION FACILITIES
  21. Chapter 28 — LUMBER YARDS AND AGRO-INDUSTRIAL, SOLID BIOMASS A…
  22. Chapter 29 — MANUFACTURE OF ORGANIC COATINGS
  23. Chapter 30 — INDUSTRIAL OVENS
  24. Chapter 31 — TENTS, TEMPORARY SPECIAL EVENT STRUCTURES AND OTH…
  25. Chapter 32 — HIGH-PILED COMBUSTIBLE STORAGE
  26. Chapter 33 — FIRE SAFETY DURING CONSTRUCTION AND DEMOLITION
  27. Chapter 34 — TIRE REBUILDING AND TIRE STORAGE
  28. Chapter 35 — WELDING AND OTHER HOT WORK
  29. Chapter 36 — MARINAS
  30. Chapter 37 — COMBUSTIBLE FIBERS
  31. Chapter 38 — RESERVED
  32. Chapter 39 — PROCESSING AND EXTRACTION FACILITIES
  33. Chapter 40 — STORAGE OF DISTILLED SPIRITS AND WINES
  34. Chapter 41 — TEMPORARY HEATING AND COOKING OPERATIONS
  35. Chapter 48 — MOTION PICTURE AND TELEVISION PRODUCTION STUDIO S…
  36. Chapter 49 — REQUIREMENTS FOR WILDLAND-URBAN INTERFACE FIRE AR…
  37. Chapter 50 — HAZARDOUS MATERIALS—GENERAL PROVISIONS
  38. Chapter 51 — AEROSOLS
  39. Chapter 52 — RESERVED
  40. Chapter 53 — COMPRESSED GASES
  41. Chapter 54 — CORROSIVE MATERIALS
  42. Chapter 55 — CRYOGENIC FLUIDS
  43. Chapter 56 — EXPLOSIVES AND FIREWORKS
  44. Chapter 57 — FLAMMABLE AND COMBUSTIBLE LIQUIDS
  45. Chapter 58 — FLAMMABLE GASES AND FLAMMABLE CRYOGENIC FLUIDS
  46. Chapter 59 — FLAMMABLE SOLIDS
  47. Chapter 60 — HIGHLY TOXIC AND TOXIC MATERIALS
  48. Chapter 61 — LIQUEFIED PETROLEUM GASES
  49. Chapter 62 — ORGANIC PEROXIDES
  50. Chapter 63 — OXIDIZERS, OXIDIZING GASES AND OXIDIZING CRYOGENI…
  51. Chapter 64 — PYROPHORIC MATERIALS
  52. Chapter 65 — PYROXYLIN (CELLULOSE NITRATE) PLASTICS
  53. ▸ Chapter 66 — UNSTABLE (REACTIVE) MATERIALS
    Overview
    1. Section 6601 — GENERAL
    2. Section 6602 — DEFINITION
    3. Section 6603 — GENERAL REQUIREMENTS
    4. Section 6604 — STORAGE
    5. Section 6605 — USE
  54. Chapter 67 — WATER-REACTIVE SOLIDS AND LIQUIDS
  55. Chapter 80 — REFERENCED STANDARDS
  56. Appendix Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON US…
  57. Appendix A — BOARD OF APPEALS
  58. Appendix B — FIRE-FLOW REQUIREMENTS FOR BUILDINGS
  59. Appendix BB — FIRE-FLOW REQUIREMENTS FOR BUILDINGS
  60. Appendix C — FIRE HYDRANT LOCATIONS AND DISTRIBUTION
  61. Appendix CC — FIRE HYDRANT LOCATIONS AND DISTRIBUTION
  62. Appendix D — FIRE APPARATUS ACCESS ROADS
  63. Appendix E — HAZARD CATEGORIES
  64. Appendix F — HAZARD RANKING
  65. Appendix G — CRYOGENIC FLUIDS—WEIGHT AND VOLUME EQUIVALENTS
  66. Appendix H — HAZARDOUS MATERIALS MANAGEMENT PLANS AND HAZARDOU…
  67. Appendix I — FIRE PROTECTION SYSTEMS—NONCOMPLIANT CONDITIONS
  68. Appendix J — BUILDING INFORMATION SIGN
  69. Appendix K — CONSTRUCTION REQUIREMENTS FOR EXISTING AMBULATORY…
  70. Appendix L — REQUIREMENTS FOR FIREFIGHTER AIR REPLENISHMENT SY…
  71. Appendix M — HIGH-RISE BUILDINGS—RETROACTIVE AUTOMATIC SPRINKL…
  72. Appendix N — INDOOR TRADE SHOWS AND EXHIBITIONS
  73. Appendix O — VALET TRASH AND RECYCLING COLLECTION IN GROUP R-2…
  74. Appendix P — TEMPORARY HAUNTED HOUSES, GHOST WALKS AND SIMILAR…
  75. Appendix Q — COMMUNITY WILDLAND-URBAN INTERFACE (WUI) FIRE HAZ…

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