This edition of NFPA 660 was approved as an American National Standard on December 6, 2024.
NFPA 660 was written by consolidating the requirements of NFPA 652, Standard on the Fundamentals of Combustible Dust; NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities; NFPA 484, Standard for Combustible Metals; NFPA 655, Standard for Prevention of Sulfur Fires and Explosions; NFPA 664, Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities; and NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids, and making them into individual chapters in NFPA 660, so that this standard provides safety requirements for all combustible dusts and particulate solids.
One effect of this consolidation is that the definitions and terminology from each document have been standardized and are all found in Chapter 3, and fundamental requirements that apply to all of the industries or commodities covered by NFPA 660 are located in the first 10 chapters. Annex material in A.1.3 explains the organization of this combined document and how to determine the requirements for a piece of equipment, building, or facility.