The Importance of Commodity Classification for High-Piled Storage Occupancies –

High-Hazard Commodities

(Blog 5 of 5 in the series)

By John Swanson

Many communities are seeing an increase in the number of warehouses built in their jurisdiction. Often, these warehouses are used for high-piled storage. Many of us have experienced and come to appreciate the ability to order something online and receive it the next day or maybe even the same day. The need for businesses to store products and materials near urban and suburban areas, so they can be accessed quickly for shipping, is a necessity for businesses to survive and thrive in today’s economy. Therefore, the need for warehouse space to store their materials will likely increase.

Commodity classifications are used in the International Fire Code (IFC), NFPA 1, and NFPA 13, Standard for the Installation of Sprinkler Systems, to identify materials in storage occupancies to determine the appropriate fire protection requirements. The square footage of the high-piled storage area, along with the commodity classification, are used to determine when sprinklers are required and the overall design of the sprinkler system.

This blog will address some of the misconceptions about high-piled storage and how to determine when additional fire protection requirements apply. Over the next few weeks, this blog series will review the different commodity classifications, starting with Class I and concluding with high hazard commodities.

What is High-Piled Combustible Storage?

The IFC defines high-piled storage as, “storage of combustible materials in closely packed piles or combustible materials on pallets, in racks, or on shelves where the top of storage is greater than 12 feet in height. Where required by the fire code official, high-piled combustible storage also includes certain high-hazard commodities…where the top of storage is greater than 6 feet in height”. The term “combustible” in high-piled combustible storage can be misleading, as high-piled storage does include non-combustible materials. It’s important to note that simply because a product is noncombustible does not exempt the building or storage arrangement from additional fire protection requirements.

NFPA 13 contains the same requirements for Class I-IV commodities. However, it is important to point out that NFPA 13 applies the same storage criteria to Group A plastics high hazard commodities, when stored over 5 feet in height. Some wonder if this is a conflict between the IFC and NFPA 13. It’s important to clarify the overall goals and objectives of each document. The codes (IFC) determine when certain fire protection systems are required, while the standards specify how fire protection systems are installed. The IFC determines when Chapter 32 and all the fire protection requirements outlined in chapter 32 apply. NFPA 13 determines how the sprinkler system, when required by the IFC, must be designed and installed to protect the materials stored.

High-Hazard Commodities

The IFC uses the term high-hazard commodities for products that present a greater fire risk than materials classified as Class I – IV. Section 3203.6 in the 2024 IFC says, high-hazard commodities are products presenting special fire hazards beyond those of Class I – IV commodities. Group A plastics are included in the high-hazard classification. The IFC and NFPA 13 break down plastics into Group A, B or C based on the heat of combustion for the material; with Group A representing the highest hazard, followed by Group B plastics, and finally Group C plastics. IFC Section 3203.4 indicates Group C plastics should be treated as a Class III commodity. IFC Section 3203.5 indicates Group B plastics should be treated as a Class IV commodity. Both the IFC and NFPA 13 require Group A plastics to meet the most stringent fire protection criteria since the heat release rate is the highest.

NFPA 13 does not use the term high-hazard commodity like the IFC does. Section 20.4.5.1 in the 2022 edition of NFPA 13 includes a comprehensive list of plastics classified as Group A. Section 20.4.5.2 then requires the Group A plastics to be subdivided as either expanded or nonexpanded. The following graph demonstrates fire severity looking at just plastic commodities.

It is important to remember that when determining commodity classification, the model codes and NFPA 13 take the product, the packaging, and the type of pallets used (wood vs. plastic) to determine the commodity classification. All three must be considered to accurately determine the commodity classification based on the IFC and NFPA 13.

Accurately determining the commodity classification is critical in determining the applicable fire protection requirements and sprinkler design. Assigning a commodity classification that does not adequately consider the product, the packaging and the type of pallet used, can have devastating consequences from a fire protection perspective.

More about the author…

John Swanson currently serves as NFSA’s Codes and Standards Specialist. In this role he provides training and education and represents NFSA on codes and standards technical committees. He currently serves as a Principal member of the NFPA 72 – National Fire Alarm and Signaling Code Technical Committee and is a member of the International Building Code (IBC) Fire Safety Committee and past member of the International Fire Code (IFC) Interpretation Committee. From 2013-2017, John served as a fire service representative to the Minnesota Board of Architecture and Engineering.