NFPA 660: Big Changes Ahead for NFPA Compliance

December 20th, 2022

Facilities collecting combustible dust need to adhere to strict standards for dust collection system design outlined by the National Fire Prevention Association (NFPA). Currently, there are six different NFPA combustible dust standards, including industry-specific standards. But soon, manufacturers will have a new combustible dust standard to contend with: NFPA 660. NFPA 660 consolidates all of these existing standards into one.

What is NFPA 660?

NFPA 660 will be a new, all-encompassing combustible dust standard for industry. It is designed to combine and replace a number of existing 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)

Fireball forming from NFPA-660.

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 will pull everything into one place to streamline compliance and mitigation decisions. 

When will NFPA 660 go into effect?

The new combustible dust standard is anticipated to be final by October 2023 and to go into effect in the fall of 2024. The complete draft is available now on the NFPA website. NFPA is soliciting public input on the draft standard until January 5, 2023. Once the draft is finalized in the fall of 2023, manufacturers will have about one year to review the new standard and prepare for it to go into effect in late 2024. 

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 will NFPA 660 introduce?

NFPA 660 does not represent a major departure from the existing NFPA standards that it will replace. 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 significant changes in some of the industry-specific chapters, most notably to the Standard for Combustible Metals section (formerly NFPA 484). (Some 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?

No major changes are expected specific to dust collection system design in NFPA 660. As with all standard updates, there will be 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 2018 version of NFPA 68 and the 2019 version of NFPA 69 remain in effect. They are scheduled for revision in 2023 and 2024, respectively, though no major changes are anticipated. 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. 

Will RoboVent dust collection systems be 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.