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311.1 Storage Group S. Storage Group S occupancy includes, among others, the use of a building or structure, or a portion thereof, for storage that is not classified as a hazardous occupancy.

This section requires that all structures (or parts thereof) designed or occupied for the storage of moderate- and low-hazard materials are to be classified in either Group S-1 (moderate hazard) or S-2 (low hazard). Small storage areas are inherent in almost any activity or occupancy. Where these are less than 10 percent of the occupancy of the story, such storage might qualify as an accessory use under Section 508.2. Storage areas in excess of 10 percent of the floor in which they are located will need to be fully addressed under the mixed occupancy requirements of Section 508.

The life safety problems in structures used for storage of moderate- and low-hazard materials are minimal because the number of people involved in a storage operation is usually small and normal work patterns require the occupants to be dispersed throughout the facility.

The problems of fire safety, particularly as they relate to the protection of stored contents, are directly associated with the amount and combustibility of the materials (including packaging) that are housed on the premises.

Storage facilities typically contain significant amounts of combustible or noncombustible materials that are kept in a common area. Because of the combustion, flammability or explosive characteristics of certain materials (see Section 307), a structure (or portion thereof) that is used to store high-hazard materials, which exceeds the maximum allowable quantities or that does not meet one of the exceptions identified in Section 307.1, cannot be classified as Group S and is to be classified as Group H, high-hazard use, and is to comply with Section 307.

Storage occupancies consist of two basic types: Groups S-1 and S-2, which are based on the properties of the materials being stored. The distinction between Groups S-1 and S-2 is similar to that between Groups F-1 and F-2, as outlined in Section 306.

311.2 Moderate-hazard storage, Group S-1. Buildings occupied for storage uses that are not classified as Group S-2, including, but not limited to, storage of the following:

Aerosols, Levels 2 and 3

Aircraft hangar (storage and repair)

Bags: cloth, burlap and paper

Bamboos and rattan


Belting: canvas and leather

Books and paper in rolls or packs

Boots and shoes

Buttons, including cloth covered, pearl or bone

Cardboard and cardboard boxes

Clothing, woolen wearing apparel


Dry boat storage (indoor)



Glues, mucilage, pastes and size


Horns and combs, other than celluloid




Motor vehicle repair garages complying with the maximum allowable quantities of hazardous materials listed in Table 307.1(1) (see Section 406.6)

Photo engravings

Resilient flooring




Tires, bulk storage of

Tobacco, cigars, cigarettes and snuff

Upholstery and mattresses

Wax candles

Buildings in which combustible materials are stored and that burn with ease are classified in Group S-1, moderate-hazard storage occupancies. Examples of the kinds of materials that, when stored, are representative of occupancies classified in Group S-1 are also listed in this section.

As defined by the IFC, a repair garage is any structure used for servicing or repairing motor vehicles. Therefore, regardless of the extent of work done (e.g., quick lube, tune-up, muffler and tire shops, painting, body work, engine overhaul), repair garages are classified as Group S-1 (see Figure 311.2) and must be in compliance with Section 406.6. In addition, to avoid a Group H classification, the amounts of hazardous materials in the garage must be less than the maximum allowable quantity per control area permitted in Tables 307.1(1) and 307.1(2).

Aircraft hangars for storage, repair or both would be classified as Group S-1. This classification correlates with the actual use of such hangars which very frequently would include some level of repair work and also works with the requirements of NFPA 409. Previous editions allowed aircraft hangars simply for storage to be classified as Group S-2. Aircraft hangers accessory to one- and two-family structures remain a Group U occupancy.


311.3 Low-hazard storage, Group S-2. Includes, among others, buildings used for the storage of noncombustible materials such as products on wood pallets or in paper cartons with or without single thickness divisions; or in paper wrappings. Such products are permitted to have a negligible amount of plastic trim, such as knobs, handles or film wrapping. Group S-2 storage uses shall include, but not be limited to, storage of the following:


Beverages up to and including 16-percent alcohol in metal, glass or ceramic containers

Cement in bags

Chalk and crayons

Dairy products in nonwaxed coated paper containers

Dry cell batteries

Electrical coils

Electrical motors

Empty cans

Food products

Foods in noncombustible containers

Fresh fruits and vegetables in nonplastic trays or containers

Frozen foods


Glass bottles, empty or filled with noncombustible liquids

Gypsum board

Inert pigments



Metal cabinets

Metal desks with plastic tops and trim

Metal parts



Oil-filled and other types of distribution transformers

Parking garages, open or enclosed

Porcelain and pottery


Talc and soapstones

Washers and dryers

Buildings in which noncombustible materials are stored are classified as Group S-2, low-hazard storage occupancies (see Figure 311.3). It is acceptable for stored noncombustible products to be packaged in combustible materials as long as the quantity of packaging is kept to an insignificant level.

As seen in Group F-1 and F-2 classifications, it is important to be able to distinguish when the presence of combustible packaging constitutes a significant fuel load. As such, a fuel load might require the building to be classified in Group S-1, moderate-hazard storage. A simple guideline to follow is the "single thickness" rule, which is when a noncombustible product is put in one layer of packaging material.

Examples of materials qualified for storage in Group S-2 storage facilities are as follows:

• Vehicle engines placed on wood pallets for transportation after assembly;

• Washing machines in corrugated cardboard boxes; and

• Soft-drink glass bottles packaged in pressed paper boxes.

Structures used to store noncombustible materials packaged in more than one layer of combustible packaging material are to be classified in Group S-1.

Examples of materials that, because of packaging, do not qualify for classification in Group S-2 are:

• Chinaware wrapped in corrugated paper and placed in cardboard boxes;

• Glassware set in expanded foam forms and placed in a cardboard box; and

• Fuel filters individually packed in pressed paper boxes, placed by the gross in a cardboard box and then stacked on a wood pallet for transportation.

An area of the IFC that is often related to Group S occupancies is Chapter 23, which regulates high- piled combustible storage [storage over 12 feet (3658 mm) in height or 6 feet (1829 mm) if the material is considered high hazard]. Chapter 23 of the IFC is focused not only on the type of materials being stored but also the height and configuration of such storage. It is important to note that not all Group S occupancies will contain high-piled storage and that high-piled storage is not limited to Group S occupancies. High-piled storage can be found in occupancies such as Group H or F.

Open and enclosed parking garages are classified as Group S-2 occupancies as long as no repair activities as discussed in the commentary to Section 311.2 occur in such buildings. A garage in a fire station, for example, that undertakes maintenance and repairs limited to cleaning, hose change, water fill, fire equipment upgrades or wheel removal for repair off premise would not constitute the same hazard associated with repair garages and would be appropriately classified as a Group S-2 classification.