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.
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).
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.
See Section C.2.
The protection requirements for the lower commodity class shall be permitted to be utilized where all of the following are met:
- 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).
- The higher hazard commodity shall be randomly dispersed with no adjacent loads in any direction (including diagonally).
- 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.
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.
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.
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:
A Class IV commodity shall be defined as a product, with or without pallets, that meets one of the following criteria:
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:
- ABS (acrylonitrile-butadiene-styrene copolymer)
- Acetal (polyformaldehyde)
- Acrylic (polymethyl methacrylate)
- Butyl rubber
- EPDM (ethylene-propylene rubber)
- FRP (fiberglass-reinforced polyester)
- Natural rubber (if expanded)
- Nitrile-rubber (acrylonitrile-butadiene-rubber)
- PET (thermoplastic polyester)
- Polyester elastomer
- PVC (polyvinyl chloride — highly plasticized, with plasticizer content greater than 20 percent) (rarely found)
- SAN (styrene acrylonitrile)
- SBR (styrene-butadiene rubber)
The following materials shall be classified as Group B:
- Cellulosics (cellulose acetate, cellulose acetate butyrate, ethyl cellulose)
- Chloroprene rubber
- Fluoroplastics (ECTFE — ethylene-chlorotrifluoro-ethylene copolymer; ETFE — ethylene-tetrafluoroethylene-copolymer; FEP — fluorinated ethylene-propylene copolymer)
- Natural rubber (not expanded)
- Nylon (nylon 6, nylon 6/6)
- Silicone rubber
The following materials shall be classified as Group C:
- Fluoroplastics (PCTFE — polychlorotrifluoroethylene; PTFE — polytetrafluoroethylene)
- Melamine (melamine formaldehyde)
- PVC (polyvinyl chloride — flexible — PVCs with plasticizer content up to 20 percent)
- PVDC (polyvinylidene chloride)
- PVDF (polyvinylidene fluoride)
- PVF (polyvinyl fluoride)
- Urea (urea formaldehyde)
Exposed commodities containing greater than 25 percent by volume expanded plastic shall be protected as an exposed expanded plastic.
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.|