Expertise | May 30, 2018

What is a Dust Hazard Analysis?

Is Combustible Dust a Real Threat?

This article reviews current NFPA Standards for Combustible Dust and examines how a Dust Hazard Analysis (DHA) helps protect your plant and its personnel.

Combustible Dust and NFPA Standards

Combustible dust is a serious safety concern in industries such as agriculture, food processing, wood products, metals, and chemicals. Between January 1, 2023, and January 1, 2024, for example, one online source recorded 263 fires, 53 explosions, 94 injuries and 62 fatalities around the world related to combustible dust, reinforcing the critical need for effective prevention strategies.

To mitigate the risks posed by combustible dust, the National Fire Protection Association (NFPA) regularly updates its combustible dust standards. The most recent edition, NFPA 660:2025 has combined the previous standards NFPA 61, NFPA 484, NFPA 652, NFPA 654, NFPA 655, and NFPA 664 into one consolidated and revised standard. NFPA 660 continues to emphasize the importance of conducting a Dust Hazard Analyses (DHA) for new and existing facilities.

What Is a Dust Hazard Analysis (DHA)?

A DHA is systematic review to identify and evaluate the potential fire, flash fire, or explosion hazards associated with the presence of one or more combustible dusts in a process or facility.¹

How is a Dust Hazard Analysis Conducted?

In existing facilities , qualified person(s)² will conduct a site visit to observe the process and identify and evaluate potential hazards. Where such hazards exist, the DHA will address specific fire, flash fire, and explosion scenarios and include the following:

Identification of safe operating ranges.
Identification of the safeguards that are already in place to manage the hazards.
Provide recommendations for additional safeguards where warranted, including a plan for implementation.

For new facilities or expansions to existing facilities, the same basic approach is taken except that it begins at the design stage. A DHA is necessary at this stage to aid the engineers, architects, and contractors so that the design and construction meet current requirements of NFPA 660. It will address proper design of buildings and building compartments as well as process equipment and systems as they relate to the hazards of combustible dust. At the completion of the new facility or addition, the Owner / Operator will have a DHA in place to support and augment their safe operating procedures.

Footnotes

¹NFPA 660 requires the DHA to be reviewed and updated at least every 5 years.

²NFPA 660 states that, “The DHA shall be performed or led by a qualified person who possesses documented experience and education regarding methods for performing a DHA and the assessment and identification of mitigation or elimination options for the fire, flash fire, explosion, and related hazards of the specific type or types of combustible dusts involved in the facility”. NFPA 660:7.7.2

About the Authors

Doug Rohkohl

As a Senior Designer at VAA, Doug regularly works with owners and design-build contractors to design feed mills, grain elevators and other agricultural bulk material handling and processing facilities from early stages of project conception through final design and construction. Doug’s 20 years of experience in agribusiness has translated into a comprehensive understanding of how different construction methods; material handling and process systems; and the NFPA affect design. His favorite part of the job is meeting with plant personnel at their facility to understand challenges and work together towards improving operations.

Eric Peterson

As a principal and senior project manager at VAA, Eric has three decades of domestic and international experience designing and constructing facilities and processes that handle combustible dusts and/or combustible particulate solids. These include facilities in animal feed, pet foot grain, grain biproducts, grain export, flour milling, oilseed extraction, malting, and wet corn milling. Eric is also is part of several technical committees for NFPA 660.

This three-part series defines the NFPA 652 guideline changes and impact to existing and new facilities. The article will also explore compelling reasons to get ahead of this regulation change.

According to the National Fire Protection Association (NFPA), 50 combustible dust accidents occurred in the United States alone between 2008 and 2012. To continue improving and reducing hazard risk in agricultural facilities, the NFPA reviews and updates their guidelines every three years. The latest, 2016 edition of NFPA 652 Standards for Combustible Dust introduces the use of a Dust Hazard Analysis (DHA). This edition’s NFPA 652 update impacts existing and new facilities that combat dust-related hazards as a result of their processes. The NFPA now advises commissioning a DHA once every five years.

What Is a Dust Hazard Analysis?

A Dust Hazard Analysis (DHA) documents potential fire, flash fire and explosion (or dust deflagration) hazards. All potential hazards are placed in one of three general categories: Not a hazard, Maybe a hazard or Deflagration hazard. In existing facilities, a licensed professional will conduct a site visit to observe the process, categorize potential hazards and provide any recommended administrative or engineering safeguards to reduce the risk of deflagration. For new facilities or facility expansions, a licensed professional can assess and incorporate safety measures in designs based on the local jurisdiction and building codes.

When considering commissioning a DHA, reach out to the Authority Having Jurisdiction and a licensed professional. These entities will confirm which codes and guidelines are used in the jurisdiction and if a DHA is required for a project. To perform the DHA and offer practical solutions, engage a licensed professional that specializes in the industry, such as an architect, mechanical engineer or fire protection engineer. A qualified professional will be knowledgeable about the facility process and have a thorough understanding of local and state codes.

Read the next parts of this series for more information:

Part 2: DHA in New and Existing Facilities

Part 3: Learning from a Dusty Past

About the Authors
Doug Rohkohl
As a Senior Designer at VAA, Doug regularly works with owners and design-build contractors to design feed mills, grain elevators and other agricultural bulk material handling and processing facilities from early stages of project conception through final design and construction. Doug’s 15 years of experience in agribusiness has translated into a comprehensive understanding of how different construction methods; material handling and process systems; and the NFPA affect design. His favorite part of the job is meeting with plant managers at their facility to understand challenges and work together towards improving operations.

Eric Peterson
Eric has two decades of domestic and international experience, including feed mills, grain export terminals, flour mills, bulk storage facilities and specialty slipform structures. Versatile in managing both engineering and construction efforts, he understands the details needed to fulfill design, constructability,
procurement and cost estimating activities. A member of the NFPA, Eric’s knowledge of material handling, mechanical and structural engineering is complemented by his technical skills in AutoCAD, P6 and Hard Dollar. Prior to joining VAA, Eric worked for a design-build contractor where he developed design concepts with clients and coordinated design and construction efforts with equipment vendors and subcontractors. Clients appreciate his global understanding of the design / construction process to accomplish operational goals and challenging facility requests.

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