Way back in the early 1990’s I learned a valuable lesson the “hard way,” and to this day, facility siting means something altogether different than how most view it. Those that work with me know I hate having combustibles such as empty pallets around chemical processes, especially flammable processes. But even non-flammable processes, such as NH3 and Cl2, are at severe risks when we allow combustibles to be stored in their proximity. I am happy to say that after years of discussion, the 2018 IFC now addresses storage of pallets (both wooded and plastic as BOTH are combustible”). At least it made it into the code, now we have to enforce it, but now 3rd party auditors have something we can use to drive process safety and fire safety excellence. The code does not specifically prohibit it, but requires any business where there is an excess of 2,500 cubic feet (71 m3) gross volume of combustible empty packing cases, boxes, barrels or similar containers, combustible pallets, rubber tires, rubber, cork or similar combustible material must obtain an “operational permit” for their AHJ. This requirement has been on the books for years, but in 2018 they added “combustible pallets” to the language.
105.6.29 Miscellaneous combustible storage. An operational permit is required to store in any building or on any premises in excess of 2,500 cubic feet (71 m3) gross volume of combustible empty packing cases, boxes, barrels or similar containers, combustible pallets, rubber tires, rubber, cork or similar combustible material.
So for all of you panicking that this will shut you down, you can rest easy, as this is a LOT of pallets, 378 of the traditional wooden pallets to be exact.
48″ X 40″ X 6″ = 11,520 cubic inches
11,520 in3 divided by 1,728 = 6.66 ft3
2,500 divided by 6.66 = 378 pallets
But there is more that can help us in improving our fire safety, and process safety as it relates to the risks idle pallet storage poses to our facilities.
For pallets stored outdoors, storage height is limited to 20 feet in Section 315.7.3 and Tables 315.6.7(1) through 315.6.7(4) provide separation criteria. Tables 315.6.7(1) and 315.6.7(3) address wood pallets. Based on Section 315.7.5, listed plastic pallets are treated the same as wood pallets, so would also fall under Tables 315.6.7(1) and 315.6.7(3). Tables 315.6.7(2) and 315.6.7(4) are for plastic pallets and would include all plastic pallets which are not listed.
The separation distance to buildings is based on two conditions. First, the number of pallets; and second, the type of building construction. As the fire resistance of the building wall increases, the separation can be reduced. As the number of pallets increases, the separation increases because the heat generated will also increase. It should be noted that even for less than 50 pallets adjacent to a masonry wall with no openings, there is still a required separation distance of 2 feet.
Note that the separation distance to buildings is different for outdoor pallet storage than the distance found in the Section 2810.7. This section covers general pallet storage at any industrial or commercial facility, whereas Section 2810 is specific to pallet manufacturing and pallet recycling facilities.
Section 315.7.4 limits the pile sizes to 400 square feet each. Tables 315.7.6(3) and 315.6.7(4) provide the separation distance between piles. For example, piles of over 200 pallets are separated into piles no more than 20 feet in height, each pile does not exceed 400 square feet, and multiple piles are separated by 45 feet, based on Table 315.7.6(3).