A risk of fire and explosion exists in most industries that deal with combustible dust. These fine particulates can become explosive when suspended in air under the right concentration. Dust-related fires or explosions can significantly damage industrial infrastructure as well as injure or kill workers and others nearby. In fact, according to the US Chemical Safety Board, there have been 386 major industrial explosions related to dust between 1980-2017. Data shows an average of 20 such dust explosions in the United States occurring annually, resulting in as many as 35 injuries and 10 fatalities annually.

The National Fire Protection Association (NFPA) dust hazard analysis was created because of such incidents. The NFPA dust hazard analysis helps facilities that deal with combustible dust to identify and manage these hazards, along with basic principles to help prevent fires and explosions. For those who work with combustible dust, it’s essential to understand what it takes to comply with the NFPA’s standards.

NFPA Standards on Combustible Dust

NFPA 652 is where dust hazard analysis begins. It’s a guide that promotes safety through awareness, management and mitigation techniques and defines dust hazard analysis. The NFPA uses dust hazard analyses to denote the specific hazards related to processes that use bulk powders or create dust. It directs businesses that handle combustible dust to identify hazards and instructs on mitigating the danger.

While NFPA standards have required hazard analyses since 2005, NFPA 652 requires further action for existing installations. This comes with a deadline, with an NFPA dust hazard analysis required for new and upgraded facilities to be completed within three years. In fact, many safety citations from the Occupational Safety and Health Administration (OSHA) list the lack of a dust hazard analysis as a prime reason for citing a business.

The current NFPA dust hazard analysis looks at the following:

  • Oxygen (including air) present in the environment
  • Fuel in the form of combustible dust and its location
  • How fuel may be dispersed
  • Sources of ignition
  • Dust containment methods and locations

All companies involved in creating, processing, or handling combustible dust must perform an NFPA dust hazard analysis. Those still utilizing simpler systems for collecting combustible dust should particularly take heed, as more complex dust collection systems have been developed to remove and separate dust. These analyses look at internal and external parts of dust collection systems to identify where they could accumulate to become a hazard.

What is an NFPA Dust Hazard Analysis? 

An NFPA dust hazard analysis is required at any facility where dust can potentially combust. It’s a tool that helps improve safety in such facilities by identifying the specific hazards posed within the processing environment. Performing an NFPA dust hazard analysis requires an experienced and well-trained professional who knows how to recognize, assess, reduce, and control risks related to combustible dust.

For businesses, it helps address safety issues that include: 

  • Administrative restrictions
  • Cleaning and maintenance procedures
  • Engineering constraints
  • Specifications for personal protective equipment
  • Training programs for employees

The goal of an NFPA dust hazard analysis is to review a facility and its processes to determine potential risks to mitigate and minimize such risks.

Requirements for NFPA Dust Hazard Analysis

The NFPA 652 standard applies to any facility that works with dust or particulate solids prone to combustion. The standard looks specifically at those involved in amalgamating, handling, making, producing, processing, transporting, or repackaging such material. The basis of the standard provides for both the identification and management of explosion and fire hazards, including provisions for managing fires and explosion hazards resulting from combustible dust.

Regarding OSHA inspections, businesses working with combustible dust should also be aware that they'll be cited for this oversight if they haven’t done a dust hazard analysis. Yet such an analysis needn’t be overly complex. All it needs to do is list each hazard and its location while stating what actions are taken to prevent fires and explosions. For each system within a production line, the analysis should also present individual parts of the system as not hazardous or possibly hazardous while also pointing out specific deflagration hazards.

When looking at each part of a system, the person performing the analysis should ask: 

  • Is the dust combustible?
  • Can the dust be exposed to air (an oxidant)?
  • Can suspension of dust in air occur?
  • Will the concentration density of dust support deflagration?
  • Is there an ignition source, and if so, is it sufficient to ignite the dust cloud?
  • What, if any, controls are in place to manage these hazards?

These requirements apply to any new or existing facilities or operations that present a combustible dust hazard, with existing facilities requiring the completion of a dust hazard analysis in agreement with Section 7.1.2 of NFPA 652. Fire code officials can additionally authorize an NFPA dust hazard analysis more quickly should they identify a danger and the facility hasn’t yet conducted such an analysis.  

Who Should Perform NFPA Dust Hazard Analysis

Often, an NFPA dust hazard analysis can be done by whoever’s most familiar with the equipment. Reviews should be conducted throughout the lifecycle of a system until it’s been decommissioned. However, more complex systems may require more people and equipment to analyze. This could include input from maintenance staff and equipment operators, who can offer insights into any recurring malfunctions and the fixes enacted that may lead to a conflagration. However, whoever conducts an NFPA dust hazard analysis should be familiar with the organization’s standards.

How Often to Perform NFPA Dust Hazard Analysis

Before enacting the NFPA 652 standard, businesses only needed to conduct an analysis of hazardous dust processes if modifications occurred, costing more than a quarter of its initial cost when installed. All facilities that work with hazardous dust were to complete an NFPA dust hazard analysis by October 2018. The standard also requires training maintenance staff, equipment operators, and other stakeholders to be aware of job-specific safeguards relating to dust hazards before they work on dust collection systems.

Prater Airlocks & NFPA Dust Hazard Analysis

To complement NFPA dust hazard analyses, Prater Industries designs its Heavy Duty PAV Series Rotary Airlock Valves in compliance with NFPA 69 standards. Updated in 2019, this standard deals with installing systems that prevent and control explosions that may occur in enclosures containing flammable dusts, gasses, mists, vapors or hybrid mixtures. Prater’s airlocks are tested in a third-party facility, undergoing thorough testing to demonstrate their ability to isolate fires and prevent their spread.

  • Abrasion-resistant models are designed for working with corrosive and abrasive materials.
  • Blow-Thru airlocks are specifically engineered to work with pneumatic conveying systems.
  • Dust Collector Series models are designed to work with hoppers, dust collectors and cyclones for general purposes.
  • Heavy-Duty PAV Series of airlocks that handle dry powdered material that flows freely within applications involving pressure differentials, including production lines that use pneumatic conveyors.

Our PAV Series airlocks are meant to meet NFPA 69 requirements and exceed them. If you’re looking for the best rotary airlock for an application that will also help meet standards for an NFPA dust hazard analysis, the experts at Prater can help. 

We understand the importance of airlock construction and how pressure and temperature during production affect an airlock’s operation. Our airlocks can be customized for specific applications, and we encourage our customers to try out Prater’s airlock calculator tool. To learn more about Prater’s various rotary airlocks and how they assist in reducing the danger of dust explosions and fires during production, don't hesitate to contact one of our expert technicians today.