Combustible Dust Standards Are Undergoing a Massive Revision (NFPA 660)

A major change is coming to the National Fire Protection Association (NFPA) standards regarding combustible dusts. Many of you have utilized the NFPA standards in the past. The combustible dust standards are in place to provide guidance on ways to identify materials that may pose fire and explosion hazards, determine where and when these hazards might occur, identify and review safeguards needed to prevent injury to personnel and damage to equipment and property, and to track the progress for improving these safeguards.

The NFPA is set to release a new standard, NFPA 660: Standard for Combustible Dusts in 2024, possibly early 2025. The new standard consolidates the general combustible dust standards of NFPA 652 with the industry specific standards of NFPA 61, 484, 654, 655, and 664.  In the new standard. Chapters 1-9 will be the general requirements for all facilities (what has been NFPA 652). Then, each of the industry-specific standards gets a chapter instead of its own individual standard.  The layout of NFPA 660, with relation to the previous set of combustible standards will be as follows:

  • Chapters 1-9: NFPA 652
  • Chapter 10: Reserved
  • Chapter 11: NFPA 61
  • Chapter 12: NFPA 484
  • Chapter 13: NFPA 654
  • Chapter 14: NFPA 655
  • Chapter 15: NFPA 664
  • The Annex from all the standards will also be combined.

Combining the standards brings many changes. Some of the main changes that come with combining the standards are the removal of redundant information (improving the layout and navigation between the chapters), the use of improved wording, moving most equipment standards to their appropriate industry specific chapter, and putting all combustible dust standards on same update schedule. The new combined standard will have less conflicts and be easier to navigate.

Removing Redundancy.

One change the comes from combining the standards is the ability to remove repeated information or stated information and data from one standard that does not align with similar information in another. With the current method of the many different standards for combustible dust there are several instances of redundant and repeated information, as well as equipment requirements that are not consistent between the standards (e.g. requirements for Air-Material Separators, bearings, etc.). Now the industry specific chapters can reference the general chapters without needing to repeat wording, decreases the number of conflicts. The Annexes being combined also allows the removal of redundant diagrams and information.

Consistent Wording

Combining the standards ensures consistent wording and definitions are applied to all industries. Using improved consistent wording should also help clarify parts of the standard. Some of the main updates to improve wording and consistency involve the terms Air-Material Separator, Fire, Flash Fire and Explosion, Deflagration Venting, and Hazard (Classified) Locations.

Qualifications For Who Can Conduct a Dust Hazard Analysis (DHA)

One section of wording that is going to get an overhaul is the definition of “Qualified Person” as the one who can conduct or lead a Combustible Dust Hazard Analysis (DHA). In the past, it was stated that a DHA shall be performed or led by a “Qualified Person” with the definition having ambiguity as to the specific qualifications needed. The revised wording has not yet been finalized, but the Standards Writing Committees are working to add specific qualification statements such as “…who possesses documented experience and education regarding methods for performing a DHA and the assessment and identification of mitigation or eliminating options for fire, flash fire, explosion, and related hazards of the specific type or types of combustible dusts involved in the facility.” This revised wording should limit the number of potentially unqualified people who offer this service. This will prevent potential catastrophic events due to a DHA being conducted or led by someone who may not be well versed in the standards, operations, or have the safety of those personnel affected at top of mind.


Another big change is how the standard handles some of the equipment design requirements such as bucket elevators, bearings, dust collectors (AMSs), etc. The new standard has removed some items from general chapter nine and adds them to the industry specific equipment design sections. This is done due to the different use cases between the industry sectors.


The combining of the standards allows for it to all be updated on the same schedule going forward. In the past each standard was on its own schedule. Now being on the same schedule should lead to fewer conflicts.

If your facility handles or generates combustible dust, if you are unsure if you material is combustible, or if OSHA, your insurance carrier, or Fire Marshall are requiring you to test the materials at your facility and have a DHA conducted, please contact us at or call us at (770) 263-6330. We are here to help.

A link to the current version of NFPA 660 can be found at

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