NFPA 660: Consolidated Combustible Dust Standards

“Pneumatic vacuums play a critical role in maintaining compliance with combustible dust (comdust) regulations. The HafcoVac uses compressed air instead of electrical components, eliminating potential ignition sources and aligning with safety standards set by organizations like OSHA and NFPA. By effectively capturing and containing dust utilizing HEPA Filtration, the HafcoVac prevents dust accumulation and dispersion, ensuring that facilities adhere to guidelines designed to minimize explosion and fire risks. This proactive approach not only protects workers and assets but also helps companies avoid fines and legal repercussions associated with non-compliance.” HAFCOVAC, www.hafcovac.com

HISTORY of Standard

Combustible dusts are fine particles that present an explosion hazard when suspended in air in certain conditions. Any combustible material can burn rapidly when in a finely divided form. If such a dust is suspended in air in the right concentration, under certain conditions, it can become explosible.

Even materials that do not burn in larger pieces (such as aluminum or iron), given the proper conditions, can be explosible in dust form. Various types of food (candy, sugar, spice, starch, flour, feed and grain); tobacco, plastics, wood, paper, pulp, rubber, pesticides, pharmaceuticals, dyes and coal; as well as metals (aluminum, chromium, iron, magnesium and zinc) can all be explosible in dust form.

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WHY is Standard Important?

The force from combustible dust explosions can cause employee deaths, injuries and damage—including the destruction of entire buildings. In many combustible dust incidents, employers and employees were unaware that a hazard even existed. Secondary explosions, which can occur when an initial explosion has dislodged more accumulated dust into the air, can be far more destructive than a primary explosion due to the increased quantity and concentration of dispersed combustible dust. Many deaths in past incidents, as well as other damage, have been caused by secondary explosions.

Combustible dust explosion hazards exist in a variety of industries, including agriculture, chemicals, food (e.g., candy, sugar, spice, starch, flour, feed), grain, fertilizer, tobacco, plastics, wood, forestry, paper, pulp, rubber, furniture, textiles, pesticides, pharmaceuticals, tire and rubber manufacturing, dyes, coal, metal processing (e.g., aluminum, chromium, iron, magnesium and zinc), recycling operations, fossil fuel power generation (coal), additive manufacturing and 3D printing.

KNOW the Requirements

A New Standard

The information and guidance contained in a number of existing combustible dust-related standards is being consolidated into one, all-encompassing new standard in a Combustible Dust Document Consolidation Plan that was approved by the National Fire Protection Agency (NFPA) Standards Council. As part of the consolidation plan, NFPA 660 combines the following standards:

• NFPA 652: Standard on the Fundamentals of Combustible Dust
• NFPA 484: Standard for Combustible Metals
• NFPA 61: Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, regarding Agriculture and Food
• NFPA 654: Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing and Handling of Combustible Particulate Solids
• NFPA 655: Standard for Prevention of Sulfur Fires and Explosions
• NFPA 664: Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities

Although a great deal of foundational information and guidance will remain the same, NFPA 660 will include some changes to definitions and clarifications made to accommodate commodity-specific hazards and processes.

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Timeline of the Consolidation Process

• The first draft had a public input closing date of January 5, 2023, and a first draft report posting date of October 25, 2023.
• The second draft’s public comment closing date was January 4, 2024, with a report posting date of October 3, 2024.
• The Motions Committee Report’s (NITMAM) closing date will be October 31, 2024. The NITMAM posting date is December 12, 2024.

Dust Explosion Prevention

Preventing combustible dust incidents begins with a thorough hazard assessment of material, operations, spaces and potential ignition sources. An inspection, housekeeping and control program should be implemented. Equipment, such as dust collection systems and filters, should be utilized along with ventilation systems that minimize the escape of dust.Housekeeping must include regular cleaning of surfaces that accumulate dust, using cleaning methods that do not generate dust clouds if ignition sources are present. Only vacuum cleaners approved for dust collection should be used.

Ignition control recommendations include the use of appropriate electrical equipment and wiring methods; and control of static electricity, smoking, open flames and sparks. Separator devices should be used to remove foreign materials capable of igniting combustibles from process materials. Heated surfaces and heating systems should be separated from dusts. IHW

More RESOURCES:

• Go to www.nfpa.org/for-professionals/codes-and-standards/nfpa-link for more about NFPA 660.
• IHW’s website has multiple articles on various aspects of combustible dust safety. To access articles, go to https://industrialhygienepub.com/ and type “combustible dust” into the search field.