NFPA13-16 Kap5

• Occupancy classifications in this standard are specifically for sprinkler design, installation, and water supply requirements.
• They are not intended as a general hazard classification.

Light Hazard Occupancies

• Light hazard occupancies are areas with low quantity or combustibility of contents.
• Fires are expected to have relatively low heat release rates.

Ordinary Hazard Occupancies

• Ordinary Hazard (Group 1) occupancies have low combustibility and a moderate amount of combustibles.

• Combustible stockpiles do not exceed 8 ft (2.4 m)

• Fires are expected to have moderate rates of heat release.

• Ordinary Hazard (Group 2) occupancies have moderate to high quantity and combustibility of contents.

• Stockpiles with moderate heat release do not exceed 12 ft (3.7 m).

• Stockpiles with high heat release do not exceed 8 ft (2.4 m).

• Dedicated and miscellaneous storage must adhere to Chapter 12 and Chapter 13 guidelines.

Extra Hazard Occupancies

• Extra Hazard (Group 1) occupancies have very high quantity and combustibility of contents, with dust, lint, or other materials present.

• Rapidly developing fires with high heat release are probable, but with little to no combustible or flammable liquids.

• Extra Hazard (Group 2) occupancies contain moderate to substantial amounts of flammable or combustible liquids, or have extensive shielding of combustibles.

Special Occupancy Hazards

Commodity Classification

• Commodity classification and protection requirements are based on the makeup of individual storage units like unit loads or pallet loads.

• The type and amount of materials in the product, primary packaging, and storage pallet are all factors in the commodity's classification.

• Nationally recognized testing agency data can be used to determine commodity classification.

• Protection is not based on the overall commodity mix in a fire area.

• Mixed commodity storage must be protected at the level of the highest classified commodity and storage arrangement, unless certain conditions are met.

• Up to 10 pallet loads of a higher hazard commodity are allowed in areas not exceeding 40,000 ft2 (3720 m2), if randomly dispersed with no adjacent loads.

• If ceiling protection is based on Class I or Class II commodities, the allowable pallet loads for Class IV or Group A plastics is reduced to five.

• Lower commodity class protection can be used if the higher hazard material is confined to a designated area which adheres to the standards for that commodity.

Pallet Types

• Wood or metal pallets, or listed equivalents, are assumed for commodity classification when loads are palletized.

• For Class I through Class IV commodities, using unreinforced polypropylene or high-density polyethylene plastic pallets increases the commodity unit's classification by one class.

• Pallets of this type should be clearly marked as unreinforced.

• For Class I through Class IV commodities, reinforced polypropylene or high-density polyethylene plastic pallets increase the commodity unit's classification by two classes, except Class IV, which becomes a cartoned unexpanded Group A plastic commodity.

• Pallets are assumed reinforced unless marked or certified otherwise.

• No increase in commodity classification is needed for Group A plastics stored on plastic pallets.

• Requirements regarding plastic pallets do not apply for ceiling-only sprinkler protection using spray sprinklers with a minimum K-factor of K-16.8 (240).

• The requirements for plastic pallets do 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, using plastic pallets other than wood, metal, or specified plastics requires specific testing by a national testing laboratory, or results in a two-class increase.

Commodity Classes

• Class I commodities are noncombustible and are placed:

  • Directly on wood pallets
  • In single-layer corrugated cartons, with or without single-thickness cardboard dividers, with or without pallets
  • Shrink-wrapped or paper-wrapped as a unit load with or without pallets

• Class II commodities are noncombustible and in slatted wooden crates, solid wood boxes, or multiple-layered corrugated cartons, with or without pallets.

• Class III commodities are made from wood, paper, natural fibers, or Group C plastics, with or without cartons, boxes, or crates and with or without pallets.

• Class III commodities can contain a limited amount (5 percent or less by weight of unexpanded plastic or 5 percent or less by volume of expanded plastic) of Group A or Group B plastics.

• Class III commodities containing a mix of both Group A expanded and unexpanded plastics must comply with specific figures depending on whether they are within cartons, boxes, or crates vs exposed.

• Class IV commodities are products with or without pallets, and meet one of the following:

  • Constructed partially or totally of Group B plastics

  • Consists of free-flowing Group A plastic materials

  • Cartoned/wooden container comprised of greater than 5% and up to 15% by weight of Group A unexpanded plastic

  • Cartoned/wooden container comprised of greater than 5% and up to 25% by volume of expanded Group A plastics

  • Cartoned/wooden container comprised of mix of Group A expanded and unexpanded plastics

  • Exposed with greater than 5% and up to 15% by weight of Group A unexpanded plastic

  • Exposed comprised of a mix of Group A expanded and unexpanded plastics

• Class IV commodities can be made of metal, wood, paper, natural or synthetic fibers, or Group B or Group C plastics.

Classification of Plastics, Elastomers, and Rubber

• Plastics, elastomers, and rubber are classified as Group A, Group B, or Group C.

• Group A plastics include:

  • ABS (acrylonitrile-butadiene-styrene copolymer)
  • Acetal (polyformaldehyde)
  • Acrylic (polymethyl methacrylate)
  • Butyl rubber
  • Cellulosics (cellulose acetate, cellulose acetate butyrate, ethyl cellulose)
  • EPDM (ethylene-propylene rubber)
  • FRP (fiberglass-reinforced polyester)
  • Natural rubber
  • Nitrile-rubber (acrylonitrile-butadiene-rubber)
  • Nylon (nylon 6, nylon 6/6)
  • PET (thermoplastic polyester)
  • Polybutadiene
  • Polycarbonate
  • Polyester elastomer
  • Polyethylene
  • Polypropylene
  • Polystyrene
  • Polyurethane
  • PVC (polyvinyl chloride — highly plasticized, with plasticizer content greater than 20 percent)
  • PVF (polyvinyl fluoride)
  • SAN (styrene acrylonitrile)
  • SBR (styrene-butadiene rubber)

• Group A plastics are further subdivided as either expanded or unexpanded.

  • Group A expanded plastic commodities either contain greater than 40% by volume of Group A expanded plastic (if cartoned or in a wooden container) or greater than 25% by volume of Group A expanded plastic (if exposed).

• Group A unexpanded plastic commodities consists either of the following, with the remaining materials of commodities being one of noncombustible, wood, paper, natural or synthetic fibers, or Group A, B or C plastics:

  • Greater than 15% by weight of Group A unexpanded plastic (if cartoned or in a wooden container); Greater than 25% and up to 40% by volume of Group A expanded plastic (if cartoned or in a wooden container)
  • A mix of Group A unexpanded and expanded plastics in compliance with Figure 5.6.3.3.3(a) (if cartoned or in a wooden container);

• Greater than 15% by weight of Group A unexpanded plastic (if exposed);

• Greater than 5% and up to 25% by volume of Group A expanded plastic (if exposed).

• A mix of Group A unexpanded and expanded plastics in compliance with Figure 5.6.3.3.3(a) (if exposed).

• Group B plastics include:

  • Chloroprene rubber
  • Fluoroplastics (ECTFE, ETFE, FEP)
  • Silicone rubber

• Group C plastics include:

  • Fluoroplastics (PCTFE, PTFE)
  • Melamine (melamine formaldehyde)
  • Phenolic
  • PVC (polyvinyl chloride — flexible — PVCs with plasticizer content up to 20 percent)
  • PVDC (polyvinylidene chloride)
  • PVDF (polyvinylidene fluoride)
  • Urea (urea formaldehyde)

Classification of Rolled Paper Storage

• The following paper classifications are used to determine sprinkler system design criteria:

• Heavyweight Class: Includes paperboard and paper stock with a basis weight of 20 lb per 1000 ft2 (9.1 kg per 92.9 m2).

• Mediumweight Class: Includes papers with a basis weight of 10 lb to 20 lb per 1000 ft2 (4.5 kg to 9.1 kg per 92.9 m2).

• Lightweight Class: Includes papers with a basis weight less than 10 lb per 1000 ft2 (4.5 kg per 92.9 m2).

• Tissue: Includes papers with a gauzy texture, sometimes transparent.

  • Defined as soft, absorbent types like crepe wadding and sanitary classes (facial tissue, paper napkins, bathroom tissue, toweling), regardless of basis weight.