Why have several regulations that cover bits and pieces of something when you can have one that covers everything? That's the thinking behind the National Fire Protection Association (NFPA) when it comes to creating a new combustible dust standard. Known as the new NFPA 660: Standard for Combustible Dusts, the goal is to combine all the existing regulations - 652, 61, 484, 654, 655 and 664 - into one that's all-encompassing.

The idea is that the regulation will provide a blueprint for how to apply relevant combustible dust guidelines for any type of facility, while also eliminating the need to purchase multiple dust standards.

In this post, we'll cover what the new NFPA 660 regulation will cover, how it will incorporate all other combustible dust standards, and when the new regulation is expected to be completed and published.

Hazards of Combustible Dust

Before we get into the new NFPA 660, it's worth taking a moment to discuss combustible dust and the hazards that it can pose to any environment. Specifically, combustible dusts are fine particles that pose an explosion risk if the right conditions are present in a confined environment. Any type of explosion - let alone one that stems from dust - can cause property damage and pose a serious safety threat to anyone within the vicinity.

Combustible dust tends to be present in facilities that handle agricultural products, metals, plastics, and chemicals. In many cases, workers may not even be aware that there is a threat. Yet, it's up to property managers and owners to be aware of any potential threat. This also includes following the rules and regulations to prevent any type of incident.

The New NFPA 660 Regulation: What You Need to Know

The NFPA 660: Standard for Combustible Dusts is designed to take all the current dust regulations and roll them into one that's all-encompassing. We'll cover more of the current standards, many of which are commodity-specific, but it's important to know that the NFPA 660 will cover them all.

Here's a look at what property managers and owners can expect from the new NFPA 660 regulation:

  • Updates to the NFPA 652: Standard on the Fundamentals of Combustible Dust and all the commodity-specific standards. More on this is to come in the forthcoming section.
  • Clarified questions on enforcement.
  • A format that is easier to navigate for owners and property managers. For instance, many of the current standards will be replaced with chapters on the specific topic covered.

It's important to note that no significant changes are expected with the publication of the new combustible dust standard. It's essentially more or less a compilation of the existing standards rolled into one regulation, with the goal of making it more cohesive and streamlined.

The public had an opportunity to weigh in on the NFPA 660, but that period ended in January 2023. The final document is expected to open again for final public comment before its final review and eventual release, which is slated for sometime in late 2024 or early 2025.

Other Combustible Dust Standards

As noted, there are a number of other combustible dust standards that will be consolidated and compiled into the new NFPA 660 regulation. When this occurs and the final document is published, all existing standards will become obsolete and be replaced by the NFPA 660.

The most significant is arguably the NFPA 652: Standard on the Fundamentals of Combustible Dust, while the other current standards are more commodity-specific. Here's a brief overview of the current existing standards:

NFPA 652

The Standard on the Fundamentals of Combustible Dust is essentially the fundamentals for combustible dust. It's an ideal resource for understanding the best practices and requirements that applicable facilities should abide by. Chapters 1-9 of the NFPA 660 are expected to cover this information.


The Standard for the Prevention of Fires and Dust Explosions in the Agricultural and Food Products Facilities, fitting to the name, this standard is relevant to understanding and preventing issues in the agriculture and food markets. Chapter 10 of the NFPA 660 is expected to cover this information.

NFPA 484

The Standard for Combustible Metals, this standard is relevant to understanding and preventing issues in the metals industry. Chapter 11 of the NFPA 660 is expected to cover this information.

NFPA 654

The Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids, the NFPA 654 is another commodity-specific standard relevant to manufacturing environments. Chapter 12 of the NFPA 660 is expected to cover this information.

NPFA 655

The Standard for Prevention of Sulfur Fires and Explosions, this standard is designed to prevent issues in environments where crushing or grinding bulk and liquid sulfur take place. Chapter 13 of the NFPA 660 is expected to cover this information.

NFPA 664

The Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities is another commodity-specific standard. Chapter 14 of the NFPA 660 is expected to cover this information.

What Happens to Existing Regulations When the New NFPA 660 Regulation is Published?

The existing standards will become obsolete, but the information they include will still continue to live on within one all-encompassing document. As the NFPA 660 currently stands now, it will begin with an update to the NFPA 652 and then the other standards that are more commodity-specific will be broken out into chapters.

There are some regulatory conflicts between the NFPA 652 and the other commodity-specific standards that we mentioned above. However, those will be resolved by the time the NFPA 660 is ready for publication.

NFPA 660 Updates (and the Impact on the Design of Dust Collection)

Though much is still unknown about what the final NFPA 660 standard will look like when it comes time for publication, we have a pretty good idea based on the previous public comment period and the existing standards and regulations. Yet, one of the most common inquiries involves how dust collection may need to be carried out in specific facilities, and how this new standard will impact that.

How does NFPA 660 affect dust collection systems?

Fitting to their name, dust collection systems collect and remove dust from the environment, thereby reducing the risk of an explosion. Current NFPA standards tend to include minimum requirements necessary to safeguard a facility.

Essentially, the NFPA 660 appears to make any dust collection design considerations clearer for owners and property managers. Dust hazard analyses, or DHAs, are still required for any new process, and they must be updated for any existing process at least once every five years.

The NFPA 660 is still likely about a year away from publication at the time of this writing, as it's expected to be released in either late 2024 or early 2025. Despite this anticipated release, now's the time for owners to begin understanding this new standard and how it will impact your specific facility. Until then, the current standards are still in effect. Stay tuned for more information on the forthcoming NFPA 660 and any opportunities to provide your input.