Heads up: There are no amended sections in this chapter.
Occupancy classifications for this standard shall relate to sprinkler design, installation, and water supply requirements only.
Occupancy classifications shall not be intended to be a general classification of occupancy hazards.
Light hazard occupancies shall be defined as occupancies or portions of other occupancies where the quantity and/or combustibility of contents is low and fires with relatively low rates of heat release are expected.
Ordinary hazard (Group 1) occupancies shall be defined as occupancies or portions of other occupancies where combustibility is low, quantity of combustibles is moderate, stockpiles of combustibles do not exceed 8 ft (2.4 m), and fires with moderate rates of heat release are expected.
Dedicated and miscellaneous storage shall be protected in accordance with Chapter 12 and Chapter 13 as applicable.
Ordinary hazard (Group 2) occupancies shall be defined as occupancies or portions of other occupancies where the quantity and combustibility of contents are moderate to high, stockpiles of contents with moderate rates of heat release do not exceed 12 ft (3.66 m), and stockpiles of contents with high rates of heat release do not exceed 8 ft (2.4 m).
Dedicated and miscellaneous storage shall be protected in accordance with Chapter 12 and Chapter 13 as applicable.
Extra hazard (Group 1) occupancies shall be defined as occupancies or portions of other occupancies where the quantity and combustibility of contents are very high and dust, lint, or other materials are present, introducing the probability of rapidly developing fires with high rates of heat release but with little or no combustible or flammable liquids.
Extra hazard (Group 2) occupancies shall be defined as occupancies or portions of other occupancies with moderate to substantial amounts of flammable or combustible liquids or occupancies where shielding of combustibles is extensive.
Commodity classification and the corresponding protection requirements shall be determined based on the makeup of individual storage units (i.e., unit load, pallet load).
When specific test data of commodity classification by a nationally recognized testing agency are available, the data shall be permitted to be used in determining classification of commodities.
Protection requirements shall not be based on the overall commodity mix in a fire area.
Unless the requirements of 5.6.1.2.3 or 5.6.1.2.4 are met, mixed commodity storage shall be protected by the requirements for the highest classified commodity and storage arrangement.
The protection requirements for the lower commodity class shall be permitted to be utilized where all of the following are met:
  1. Up to 10 pallet loads of a higher hazard commodity, as described in 5.6.3 and 5.6.4, shall be permitted to be present in an area not exceeding 40,000 ft2 (3716 m2).
  2. The higher hazard commodity shall be randomly dispersed with no adjacent loads in any direction (including diagonally).
  3. Where the ceiling protection is based on Class I or Class II commodities, the allowable number of pallet loads for Class IV or Group A plastics shall be reduced to five.
The protection requirements for the lower commodity class shall be permitted to be utilized in the area of lower commodity class, where the higher hazard material is confined to a designated area and the area is protected to the higher hazard in accordance with the requirements of this standard.
When loads are palletized, the use of wood or metal pallets, or listed pallets equivalent to wood, shall be assumed in the classification of commodities.
For Class I through Class IV commodities, when unreinforced polypropylene or unreinforced high-density polyethylene plastic pallets are used, the classification of the commodity unit shall be increased one class.
Unreinforced polypropylene or unreinforced high-density polyethylene plastic pallets shall be marked with a permanent symbol to indicate that the pallet is unreinforced.
For Class I through Class IV commodities, when reinforced polypropylene or reinforced high-density polyethylene plastic pallets are used, the classification of the commodity unit shall be increased two classes except for Class IV commodity, which shall be increased to a cartoned unexpanded Group A plastic commodity.
Pallets shall be assumed to be reinforced if no permanent marking or manufacturer's certification of nonreinforcement is provided.
No increase in the commodity classification shall be required for Group A plastic commodities stored on plastic pallets.
For ceiling-only sprinkler protection, the requirements of 5.6.2.2 and 5.6.2.3 shall not apply where plastic pallets are used and where the sprinkler system uses spray sprinklers with a minimum K-factor of K-16.8 (240).
The requirements of 5.6.2.2 through 5.6.2.7 shall not apply to nonwood pallets that have demonstrated a fire hazard that is equal to or less than wood pallets and are listed as such.
For Class I through Class IV commodities stored on plastic pallets when other than wood, metal, or polypropylene or high-density polyethylene plastic pallets are used, the classification of the commodity unit shall be determined by specific testing conducted by a national testing laboratory or shall be increased two classes.
A Class I commodity shall be defined as a noncombustible product that meets one of the following criteria:
  1. Placed directly on wood pallets
  2. Placed in single-layer corrugated cartons, with or without single-thickness cardboard dividers, with or without pallets
  3. Shrink-wrapped or paper-wrapped as a unit load with or without pallets
A Class II commodity shall be defined as a noncombustible product that is in slatted wooden crates, solid wood boxes, multiple-layered corrugated cartons, or equivalent combustible packaging material, with or without pallets.
A Class III commodity shall be defined as a product fashioned from wood, paper, natural fibers, or Group C plastics with or without cartons, boxes, or crates and with or without pallets.
A Class III commodity shall be permitted to contain a limited amount (5 percent by weight or volume or less) of Group A or Group B plastics.
A Class IV commodity shall be defined as a product, with or without pallets, that meets one of the following criteria:
  1. Constructed partially or totally of Group B plastics
  2. Consists of free-flowing Group A plastic materials
  3. Contains within itself or its packaging an appreciable amount (5 percent to 15 percent by weight or 5 percent to 25 percent by volume) of Group A plastics
The remaining materials shall be permitted to be metal, wood, paper, natural or synthetic fibers, or Group B or Group C plastics.
Plastics, elastomers, and rubber shall be classified as Group A, Group B, or Group C.
The following materials shall be classified as Group A:
  1. ABS (acrylonitrile-butadiene-styrene copolymer)
  2. Acetal (polyformaldehyde)
  3. Acrylic (polymethyl methacrylate)
  4. Butyl rubber
  5. EPDM (ethylene-propylene rubber)
  6. FRP (fiberglass-reinforced polyester)
  7. Natural rubber (if expanded)
  8. Nitrile-rubber (acrylonitrile-butadiene-rubber)
  9. PET (thermoplastic polyester)
  10. Polybutadiene
  11. Polycarbonate
  12. Polyester elastomer
  13. Polyethylene
  14. Polypropylene
  15. Polystyrene
  16. Polyurethane
  17. PVC (polyvinyl chloride — highly plasticized, with plasticizer content greater than 20 percent) (rarely found)
  18. SAN (styrene acrylonitrile)
  19. SBR (styrene-butadiene rubber)
The following materials shall be classified as Group B:
  1. Cellulosics (cellulose acetate, cellulose acetate butyrate, ethyl cellulose)
  2. Chloroprene rubber
  3. Fluoroplastics (ECTFE — ethylene-chlorotrifluoro-ethylene copolymer; ETFE — ethylene-tetrafluoroethylene-copolymer; FEP — fluorinated ethylene-propylene copolymer)
  4. Natural rubber (not expanded)
  5. Nylon (nylon 6, nylon 6/6)
  6. Silicone rubber
The following materials shall be classified as Group C:
  1. Fluoroplastics (PCTFE — polychlorotrifluoroethylene; PTFE — polytetrafluoroethylene)
  2. Melamine (melamine formaldehyde)
  3. Phenolic
  4. PVC (polyvinyl chloride — flexible — PVCs with plasticizer content up to 20 percent)
  5. PVDC (polyvinylidene chloride)
  6. PVDF (polyvinylidene fluoride)
  7. PVF (polyvinyl fluoride)
  8. Urea (urea formaldehyde)
Group A plastics shall be further subdivided as either expanded or nonexpanded.
If a cartoned commodity is more than 40 percent (by volume) expanded plastic, it shall be protected as a cartoned expanded plastic.
Exposed commodities containing greater than 25 percent by volume expanded plastic shall be protected as an exposed expanded plastic.
For the purposes of this standard, the classifications of paper described in 5.6.5.1 through 5.6.5.4 shall apply and shall be used to determine the sprinkler system design criteria.
Heavyweight class shall be defined so as to include paperboard and paper stock having a basis weight [weight per 1000 ft2 (92.9 m2)] of 20 lb (9.1 kg).
Mediumweight class shall be defined so as to include all the broad range of papers having a basis weight [weight per 1000 ft2 (92.9 m2)] of 10 lb to 20 lb (4.5 kg to 9.1 kg).
Lightweight class shall be defined so as to include all papers having a basis weight [weight per 1000 ft2 (92.9 m2)] of 10 lb (4.5 kg).
Tissue shall be defined so as to include the broad range of papers of characteristic gauzy texture, which, in some cases, are fairly transparent.
For the purposes of this standard, tissue shall be defined as the soft, absorbent type, regardless of basis weight — specifically, crepe wadding and the sanitary class including facial tissue, paper napkins, bathroom tissue, and toweling.
Chapter 6 was revised by a tentative interim amendment (TIA). See page 1.
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