The most current editions of NFPA 13 (2019), Standard for the Installation of Sprinkler Systems, and FM Global Property Loss Prevention Data Sheet (FMDS) 3-26 (April 2019), Sprinkler Design for Non-Storage Occupancies, have relocated or revised the guidance for fire protection of miscellaneous, work-in-process and low-piled storage in non-storage occupancies (i.e., manufacturing plants).
The changes were among many in the 2019 edition of NFPA 13 and the location of the guidance is prone to be missed by fire protection professionals. The previous NFPA 13 (2016) guidance was included in its own chapter (Chapter 13 entitled “Miscellaneous and Low-Piled Storage”). In the 2019 edition, the guidance is included within Chapter 4 in Section 4.3 Classification of Hazard, where it can easily be overlooked.
Per NFPA 13, “Miscellaneous Storage” is storage that does not exceed 12 ft. (3.66 m) in height, is incidental to another occupancy use group, does not constitute more than 10% of the building area or 4,000 sq. ft. (370 sq. m) of the sprinklered area, whichever is greater. Furthermore, miscellaneous storage must not exceed 1,000 sq. ft. (93 sq. m) in one pile or area and miscellaneous storage must be separated from other storage piles or areas by at least 25 ft. (7.6 m).
Work-in-process (WIP) storage within a manufacturing plant is a typical example of Miscellaneous Storage and should conform to the above noted storage height/area limitations.
Low-piled storage is solid-piled, palletized, rack storage, bin box, and shelf storage up to 12 ft. (3.66 m) in height. This is storage within a building/area designed as a storage use group; hence, there are no area limitations. Protection should be provided as per Table 4.3.1.7.1 for the given commodity, storage type, storage height and ceiling height.
FMDS 3-26 changed their recommendations on work-in-process storage and added new guidance based on testing of low-piled storage to a new Table 3. This guidance is engineered toward the levels of storage common to non-storage occupancies. The area limitations for up to Class 3 commodities remain 200 sq. ft. (20 sq. m). The area limitation for plastic-containing commodities has been reduced from 200 sq. ft. (20 sq. m) to 64 sq. ft. (6 sq. m), equivalent to four, 4 x 4 ft. pallet loads).
FMDS 3-26 Section 2.3.2 defines Incidental Storage as storage of Class 1-3 commodities up to 10 ft. and no more than 200 sq. ft. as incidental to the non-storage occupancy and recommends protection for the non-storage (e.g., manufacturing) occupancy. Similarly, up to 64 sq. ft. of plastic commodities stored up to 6 ft. high can be treated as incidental. Multiple areas of storage within these limits may still be considered as incidental to the occupancy is separated by minimum 8 ft. aisles.
If storage areas exceed these area limitations, but not the height limitations, then FM Global then considers the storage as low-piled storage and recommends protecting it as per Table 3 in FMDS 3-26. If the height limitations are also exceeded, then FMDS 8-9, Storage of Class 1, 2, 3, 4 and Plastic Commodities, should be used to determine the sprinkler demand.
Risk Logic can help you design adequate automatic sprinkler protection (using FM Global or NFPA standards) for the miscellaneous, work-in-process, low-piled and high-piled storage at your facility. Please contact us for additional details.