NFPA 13 (2013) Chapter 5 Classification of Occupancies and Commodities

5.1* Classification of Occupancies.

5.1.1 Occupancy classifications for this standard shall relate to sprinkler design, installation, and water
supply requirements only.
5.1.2 Occupancy classifications shall not be intended to be a general classification of occupancy hazards.
5.2* Light Hazard Occupancies. 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.
5.3* Ordinary Hazard Occupancies.
5.3.1* Ordinary Hazard (Group 1).
5.3.1.1 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.
5.3.1.2 Dedicated and miscellaneous storage shall be protected in accordance with Chapter 12 and
Chapter 13 as applicable.
5.3.2* Ordinary Hazard (Group 2).
5.3.2.1 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).
5.3.2.2 Dedicated and miscellaneous storage shall be protected in accordance with Chapter 12 and
Chapter 13 as applicable.
5.4 Extra Hazard Occupancies.
5.4.1* Extra Hazard (Group 1). 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.
5.4.2* Extra Hazard (Group 2). 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.
5.5* Special Occupancy Hazards.

A.5.1 Occupancy examples in the listings as shown in the various hazard classifications are intended to
represent the norm for those occupancy types. Unusual or abnormal fuel loadings or combustible
characteristics and susceptibility for changes in these characteristics, for a particular occupancy, are
considerations that should be weighed in the selection and classification.
The light hazard classification is intended to encompass residential occupancies; however, this is not
intended to preclude the use of listed residential sprinklers in residential occupancies or residential
portions of other occupancies.
A.5.2 Light hazard occupancies include occupancies having uses and conditions similar to the following:
(1) Animal shelters
(2) Churches
(3) Clubs
(4) Eaves and overhangs, if of combustible construction with no combustibles beneath
(5) Educational
(6) Hospitals, including animal hospitals and veterinary facilities
(7) Institutional
(8) Kennels
(9) Libraries, except large stack rooms
(10) Museums
(11) Nursing or convalescent homes
(12) Offices, including data processing
(13) Residential
(14) Restaurant seating areas
(15) Theaters and auditoriums, excluding stages and prosceniums
(16) Unused attics
Note that it is not the committee’s intent to automatically equate library bookshelves with ordinary
hazard occupancies or with library stacks. Typical library bookshelves of approximately 8 ft (2.4 m) in
height, containing books stored vertically on end, held in place in close association with each other, with
aisles wider than 30 in. (762 mm) can be considered to be light hazard occupancies. Similarly, library
stack areas, which are more akin to shelf storage or record storage, as defined in NFPA 232, should be
considered to be ordinary hazard occupancies.

A.5.3 For purposes of these definitions, Class I, Class II, Class III, and Class IV commodities would be
considered to have moderate rates of heat release, while Group A plastics would be considered to have
high rates of heat release. Stockpiles are considered to include display merchandise (mercantile) and
arrangements of combustibles ancillary to operations within the occupancy as opposed to dedicated
storage areas where the fire loading is generally more severe.
A.5.3.1 Ordinary hazard (Group 1) occupancies include occupancies having uses and conditions similar
to the following:
(1) Automobile parking and showrooms
(2) Bakeries
(3) Beverage manufacturing
(4) Canneries
(5) Dairy products manufacturing and processing
(6) Electronic plants
(7) Glass and glass products manufacturing
(8) Laundries
(9) Restaurant service areas

A.5.3.2 Ordinary hazard (Group 2) occupancies include occupancies having uses and conditions similar
to the following:
(1) Agricultural facilities
(2) Barns and stables
(3) Cereal mills
(4) Chemical plants — ordinary
(5) Confectionery products
(6) Distilleries
(7) Dry cleaners
(8) Exterior loading docks (Note that exterior loading docks only used for loading and unloading of
ordinary combustibles should be classified as OH2. For the handling of flammable and combustible
liquids, hazardous materials, or where utilized for storage, exterior loading docks and all interior loading
docks should be protected based upon the actual occupancy and the materials handled on the dock, as
if the materials were actually stored in that configuration.)
(9) Feed mills
(10) Horse stables
(11) Leather goods manufacturing
(12) Libraries — large stack room areas
(13) Machine shops
(14) Metal working
(15) Mercantile
(16) Paper and pulp mills
(17) Paper process plants
(18) Piers and wharves
(19) Plastics fabrication, including blow molding, extruding, and machining; excluding operations using
combustible hydraulic fluids
(20) Post offices
(21) Printing and publishing
(22) Racetrack stable/kennel areas, including those stable/ kennel areas, barns, and associated buildings
at state, county, and local fairgrounds
(23) Repair garages
(24) Resin application area
(25) Stages
(26) Textile manufacturing
(27) Tire manufacturing
(28) Tobacco products manufacturing
(29) Wood machining
(30) Wood product assembly
A.5.4.1 Extra hazard (Group 1) occupancies include occupancies having uses and conditions similar to
the following:
(1) Aircraft hangars (except as governed by NFPA 409)
(2) Combustible hydraulic fluid use areas
(3) Die casting
(4) Metal extruding
(5) Plywood and particleboard manufacturing
(6) Printing [using inks having flash points below 100°F (38°C)]
(7) Rubber reclaiming, compounding, drying, milling, vulcanizing
(8) Saw mills
(9) Textile picking, opening, blending, garnetting, or carding, combining of cotton, synthetics, wool
shoddy, or burlap
(10) Upholstering with plastic foams
A.5.4.2 Extra hazard (Group 2) occupancies include occu-
pancies having uses and conditions similar to the following:
(1) Asphalt saturating
(2) Flammable liquids spraying
(3) Flow coating
(4) Manufactured home or modular building assemblies (where finished enclosure is present and has
combustible interiors)
(5) Open oil quenching
(6) Plastics manufacturing
(7) Solvent cleaning
(8) Varnish and paint dipping

5.6* Commodity Classification. See Section C.2.

5.6.1 General.
5.6.1.1* Classification of Commodities.
5.6.1.1.1 Commodity classification and the corresponding protection requirements shall be determined
based on the makeup of individual storage units (i.e., unit load, pallet load).
5.6.1.1.2 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.
5.6.1.2 Mixed Commodities.
5.6.1.2.1 Protection requirements shall not be based on the overall commodity mix in a fire area.
5.6.1.2.2 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.
5.6.1.2.3 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 m)
(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.
5.6.1.2.4 Mixed Commodity Segregation. 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.
5.6.2 Pallet Types.
5.6.2.1 General. 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.
5.6.2.2* Unreinforced Plastic Pallets. 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.
5.6.2.2.1 Unreinforced polypropylene or unreinforced highdensity polyethylene plastic pallets shall be
marked with a permanent symbol to indicate that the pallet is unreinforced.
5.6.2.3* 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.
5.6.2.3.1 Pallets shall be assumed to be reinforced if no permanent marking or manufacturer’s
certification of nonreinforcement is provided.
5.6.2.4 No increase in the commodity classification shall be required for Group A plastic commodities
stored on plastic pallets.
5.6.2.5 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).
5.6.2.6 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.
5.6.2.7 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.
5.6.3* Commodity Classes.
5.6.3.1* Class I. 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
5.6.3.2* Class II. 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.
5.6.3.3* Class III.
5.6.3.3.1 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.
5.6.3.3.2 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.
5.6.3.4* Class IV.
5.6.3.4.1 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
5.6.3.4.2 The remaining materials shall be permitted to be metal, wood, paper, natural or synthetic
fibers, or Group B or Group C plastics.
5.6.4* Classification of Plastics, Elastomers, and Rubber. Plastics, elastomers, and rubber shall be
classified as Group A, Group B, or Group C.
5.6.4.1* Group A. 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)

5.6.4.2 Group B. 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-
tetrafluoroethylenecopolymer; FEP — fluorinated ethylene-propylene copolymer)
(4) Natural rubber (not expanded)
(5) Nylon (nylon 6, nylon 6/6)
(6) Silicone rubber
5.6.4.3 Group C. 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)
5.6.4.4 Group A plastics shall be further subdivided as either expanded or nonexpanded.

5.6.4.4.1 If a cartoned commodity is more than 40 percent (by volume) expanded plastic, it shall be
protected as a cartooned expanded plastic.
5.6.4.4.2 Exposed commodities containing greater than 25 percent by volume expanded plastic shall be
protected as an exposed expanded plastic.
5.6.5* Classification of Rolled Paper Storage. 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.
5.6.5.1 Heavyweight Class. 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).
5.6.5.2 Mediumweight Class. Mediumweight class shall be defined so as to include all the broad range
of papers having a basis weight [weight per 1000 ft 2 (92.9 m2)] of 10 lb to 20 lb (4.5 kg to 9.1 kg).
5.6.5.3 Lightweight Class. 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).
5.6.5.4 Tissue.
5.6.5.4.1 Tissue shall be defined so as to include the broad range of papers of characteristic gauzy
texture, which, in some cases, are fairly transparent.
5.6.5.4.2 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.
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