NFPA 660: Big Changes Ahead for NFPA Compliance

NFPA 660 Is Here. What Does That Mean for You?

The National Fire Prevention Association (NFPA) has updated and consolidated its combustible dust standards into a new overarching standard: NFPA 660. The new standard went into effect on December 6, 2024 and replaces six older standards, including both general and industry-specific standards.

The good news? NFPA 660 does not deviate significantly from existing standards such as NFPA 652, Standard on the Fundamentals of Combustible Dust. Still, facilities handling combustible dust should update their compliance records to incorporate the new standard and use it moving forward when making compliance decisions.

What is NFPA 660?

NFPA 660 Standard for Combustible Dust and Particulate Solids is a new, all-encompassing combustible dust standard for industry. It combines and replaces a number of older NFPA standards, including:

• NFPA 61 Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities (2020 latest version)
• NFPA 484 Standard for Combustible Metals (2022 latest version)
• NFPA 652 Standard on the Fundamentals of Combustible Dust (2019 latest version)
• NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids (2020 latest version)
• NFPA 655 Standard for the Prevention of Sulfur Fires and Explosions (2017 latest version)
• NFPA 664 Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities (2020 latest version)

Why do we need a new combustible dust standard?

NFPA’s stated purpose in creating the new standard is to consolidate all relevant information, recommendations and guidelines for combustible dust into one comprehensive document. This will make it easier for manufacturers to comply with the most recent standards and ensure they are following up-to-date best practices for protecting their facilities from a combustible dust explosion.

Previously, many manufacturers needed to consult multiple different standards—including NFPA 652, Standard on the Fundamentals of Combustible Dust; NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids; and industry-specific (or commodity-specific) standards—when designing mitigation strategies for combustible dust in their facilities. The new standard pulls everything into one place to streamline compliance and mitigation decisions.

Will NFPA 660 be legally enforceable?

NFPA standards are not by themselves enforceable by law. They become law when referred to in regulation by the Occupational Safety and Health Administration (OSHA) or another regulatory body. Regulations may refer to a specific NFPA standard or simply require employers to follow the most up-to-date standard. In any case, employers should assume that when NFPA 660 goes into effect in the fall of 2024, this will be the standard they will be held to by national, state and local regulatory enforcement bodies.

What is covered in NFPA 660?

NFPA 660 consolidates information in several existing combustible dust standards. The first nine chapters are an update of NFPA 652, Standard on the Fundamentals of Combustible Dust. Topics covered include:

• The scope, purpose, applications and administration of the standard
• Research and references
• Combustible dust definitions
• General requirements
• Hazard identification
• The performance-based design option
• The Dust Hazard Analysis (DHA) requirement
• Management systems
• Hazard management (mitigation and prevention)

The final chapters and appendices cover material from the rest of the consolidated standards, including NFPA 654. Industry- or application-specific chapters include:

• Agricultural and food processing facilities
• Combustible metals
• Sulfur fires and explosions
• Wood processing and woodworking facilities

Extensive appendices provide additional detail on a number of topics, including:

• Examples of the DHA
• Supplementary information on highly combustible metal dusts, including magnesium, lithium, titanium, tantalum and zirconium
• Material characterization and testing
• Fire protection (extinguishing/suppression)
• Explosion protection
• Isolation and deflagration propagation prevention methods
• Combustible dust test data

What changes does NFPA 660 introduce?

NFPA 660 does not represent a major departure from the existing NFPA standards that it replaces. As with every standard update, manufacturers can expect to see some clarifications to existing requirements and additional information based on new technologies, test methods or research as well as a harmonization of terms, descriptions and analytical values that may differ between commodity-specific standards.

The largest changes are anticipated in the Hazard Management: Mitigation and Prevention chapter, which required extensive work to integrate and harmonize all of the industry-, process- or material-specific information from the replaced standards. Most of these changes are related to specific production equipment; no significant changes were made to sections for building construction requirements or to the centralized vacuum cleaning, pneumatic conveying and dust collection section.

There are also some changes in some of the industry-specific chapters, most notably to the Standard for Combustible Metals section (formerly NFPA 484). (Most of these changes were already put in place in the 2022 revision of NFPA 484.)

NFPA 664, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids, has been picked up largely unchanged in Chapter 13.

Most of the remaining changes simply improve wording for greater clarity. For example:

• Additional definitions.
• Clarification on sampling requirements for combustible dust and when the use of historical data is allowed.
• Clarifications on the requirements for the use of the performance-based design option.
• Affirmation that all new and existing facilities and processes that handle combustible dust must have a completed DHA, along with some clarifications on the DHA process.
• Minor updates and clarifications to the management systems chapter.

What does NFPA 660 mean for dust collection system design?

There are no major changes specific to dust collection system design in NFPA 660. As with all standard updates, there are some clarifications and changes in wording. Most of this information falls under Chapter 9, Hazard Management: Mitigation and Prevention and Chapter 13: Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids.

What about NFPA 68 and NFPA 69?

NFPA 68 Standard on Explosion Protection by Deflagration Venting and NFPA 69 Standard on Explosion Prevention Systems are not part of the NFPA 660 consolidation plan. As of this writing, the 2023 version of NFPA 68 and the 2024 version of NFPA 69 remain in effect. These explosion safety standards apply to a variety of different kinds of systems, including dust collection systems, and are not limited to explosions caused by combustible dust. Employers must comply with these standards in addition to all other standards related to combustible dust.

Are RoboVent dust collection systems compliant with NFPA 660?

RoboVent is a leader in dust collector safety, including fire and explosion safety. We are committed to ensuring that our dust collectors and installed systems comply with all relevant NFPA standards for fire and explosion safety, including the new combustible dust standards. Our engineering teams will review all new standards related to combustible dust to ensure that our system design is NFPA-compliant.

It is the responsibility of the system owner/operator to perform required maintenance and operate the system in accordance with recommended configurations and operating limits to ensure continued compliance after installation. Before making any changes to your installed RoboVent dust collection system, talk to a RoboVent system designer to make sure that the proposed changes will not put your system out of compliance with NFPA standards.

Need help with combustible dust management? Talk to the combustible dust experts at RoboVent. We can help you assess your current system, plan your DHA, or design a new dust collection system that complies with all NFPA standards and OSHA regulations.

Download our Visual Guide to Combustible Dust.