Combustible Dust – NFPA 660 is Here

The National Fire Protection Association (NFPA) issued a new, consolidated standard for Combustible Dusts and Particulate Solids as NFPA 660 (effective December 6, 2024). A combustible dust is any finely divided solid material that presents a flash fire or explosion hazard when suspended in air or other oxidizing medium. The United States Chemical Safety Board identified¹ more than 250 combustible dust incidents between 1980 and 2005 resulting in over 100 fatalities and more than 700 injuries. Combustible dust incidents, including flash fires and explosions, can also result in catastrophic damage to industrial facilities and the surrounding community.

Legacy NFPA Standards

NFPA 660 brings together all previous standards, identified below, into a single document, unifying terminology and addressing inconsistencies between the general fundamentals standard and those specific to certain industries or materials. While it does not significantly alter compliance requirements, it provides clearer guidance to help companies across various sectors better protect their workers and facilities. For example, NFPA 660 establishes vacuuming as the preferred housekeeping method. In contrast, NFPA 664 did not specify a preferred method.

Facility Obligations

NFPA 660 requires facilities to revalidate their Dust Hazard Analyses (DHA) every five years. Under previously applicable standards for general industrial facilities, sulfur processing facilities, and wood processing/woodworking facilities required these facilities to complete a DHA by September 7, 2020; therefore, the five-year window is rapidly closing. Agricultural and food processing facilities were last required to complete a DHA by January 1, 2022.

A DHA is a systematic review to evaluate potential for a flammable atmosphere, fire, flash fire, and explosion hazards associated with combustible dust generated or processed at a facility.

Chapter 7 of NFPA 660 establishes requirements for DHAs. Items to consider as part of a DHA include:

• Hazard Identification;
• Identification of safeguards in place to manage fire, deflagration, and explosion risk; and
• Recommendations for additional safeguards, if appropriate.

Chapter 8 of NFPA 660 establishes management system requirements including the following elements:

• Operating procedures;
• Housekeeping;
• Hot work permit program;
• Personal protective equipment;
• Inspection, testing, and maintenance;
• Contractor requirements;
• Incident investigations;
• Management of change; and
• Management system review.

While NFPA 660 is a voluntary standard, it is commonly incorporated by reference, thus becoming a facility requirement by:

• The Occupational Safety and Health Administration (OSHA) under the General Duty Clause;
• Insurance providers during risk evaluation; and
• Local fire authorities or Authorities Having Jurisdiction (AHJ), under the International Fire Code or state local equivalent.

ALL4 has provided support for DHA combustible dust hazards mitigation to facilities using an established process that meets both regulatory expectations and client operational needs, including:

1. On-site review focused on dust-generating operations;
2. Identification and ranking of potential deflagration hazards;
3. Evaluation of existing controls and recommended actions; and
4. Documentation to support regulatory, insurer, and internal review

The clock is ticking on the five-year revalidation window. It is critical to initiate the process as soon as possible to allow for sufficient time for scheduling, internal coordination, and implementation of any recommended measures before regulatory or insurance reviews occur. If you are interested in learning how NFPA 660 may affect your facility, please contact your ALL4 project manager or Michael McHale at 610.422.1131 or mmchale@all4inc.com.

¹https://www.csb.gov/recommendations/mostwanted/combustibledust/