The 2019 edition of the standard for combustible metals, NFPA 484-2019, has been released. It is a complete reorganization of the 2015 version of the document.
Industrial practices are challenged with instilling order, as, although it might often seem to be the opposite, the universe leans towards chaos and disorder. As time passes by, objects degrade and corrode, organic matter rots and spoils, and the ever-persistent concept of entropy influences disorder over time. More often than not, disorder is more probable than order.
On the more-immediate subject of disorder and the inexorable plunge into chaos, there’s combustion. Combustible materials represent a flash-fire hazard or explosion hazard, and a handful of metals—magnesium, titanium, zirconium, sodium, lithium, and potassium, just to name a few—are combustible. While these metals aren’t likely to spontaneously combust in their end use form, adequately controlling them and their associated dusts in facilities is useful for mitigating any hazards.
Fires emerging from the ignition of combustible metals are designated Class D fires. Therefore, any fire extinguishers labeled Class D are intended to be used solely for extinguishing conflagrations erupting from combustible metals. Class D fire extinguishers, while mentioned in NFPA 484-2019, are more thoroughly addressed in the standard for portable fire extinguishers, NFPA 10.
NFPA 484-2019 instead details guidelines for the production, processing, finishing, handling, recycling, storage, and use of metals and alloys that are in a form capable of combustion or explosion. With this, the American National Standard addresses a range of concepts, including the means of determining the combustibility of a metal, hazard analysis, the control of ignition sources, and information unique to nanometal powders, additive manufacturing, alkali metals, and legacy metals.
Many of the changes made to NFPA 484-2019 were included to better align it with related NFPA standards, particularly NFPA 652-2019: Standard on the Fundamentals of Combustible Dust. To meet this goal, NFPA 484-2019 includes a new Chapter 7 on Dust Hazard Analysis, and it features substantial changes to Chapter 4 on general guidelines and new definitions in Chapter 3.
The section on electrical area classification in NFPA 484-2019 was also updated to clarify that the committee does not agree with the definition of combustible dust found in the National Electrical Code.
Additional revisions were made to NFPA 484 to keep it current. This includes new chapters on nanometals (Chapter 12) and additive manufacturing (Chapter 13). For clarity, Chapter 11, Powder and Dust Collection and Centralized Vacuum Systems, was completely rewritten. Furthermore, in NFPA 484-2019, the previously separate and distinct guidelines for aluminum, magnesium, niobium, tantalum, titanium, zirconium, and hafnium are now consolidated into Chapter 15, Legacy Metals.
NFPA 484-2019: Standard For Combustible Metals, 2019 Edition is available on the ANSI Webstore.