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Safeguarding Your Workspace: Strategies to Prevent Industrial Dust Collector Explosions
• High-speed abort gates integrated into the inlet or outlet ducting of a dust collection system reroute potential ignition sources away from the collector, thereby averting potential explosions and blocking flames and burning debris from entering the facility via the return air system. A mechanical barrier then redirects airflow to a secure area. A spark detection system, positioned at an adequate distance upstream to ensure ample reaction time, sets the abort gate in motion.
Passive Systems
Passive systems respond immediately after an event to prevent the deflagration from spreading to other areas and causing further damage. Many facility operators prefer passive systems to active systems because they are significantly less expensive and do not require regular recertification. Passive systems control the speed of explosions by releasing pressure once it reaches a certain threshold. Below are commonly used passive explosion protection systems:
• Explosion venting is the most commonly used method for protecting industrial dust collectors. When the dust inside the collector combusts, pressure rapidly increases. In this event, explosion vents open, allowing the pressure and flame front to exit in a safe direction. NFPA 68 – Standard on Explosion Protection by Deflagration Venting outlines specific criteria for these venting systems’ design, location, installation, maintenance and proper use.
• Explosion isolation valves installed in the inlet ducting serve as a mechanical barrier. Their primary purpose is to prevent the explosion flame and pressure from propagating through the ducts and reaching the process area. Normal airflow keeps the flap plate open. However, in the event of an explosion, the sudden pressure wave triggers the flap to close swiftly, effectively containing the flames and smoke within the duct system.
• An integrated safety monitoring filter safeguards downstream equipment and work areas. It is positioned on top of a dust collector, serving as a flame front barrier. In the event of an explosion in the dust collector, the filter retains the dust inside, preventing the flame front from entering the workspace. The iSMF complies with NFPA-mandated design options and effectively acts as a flame front arrestor for ST1 and ST2 combustible dusts.
• Flameless vents can be placed over a standard explosion vent to suppress the flame front as it exits the vented area, preventing it from escaping the device. This enables the use of conventional venting indoors, even in situations where it might otherwise pose risks to personnel or lead to secondary explosions. However, it’s essential to establish a safe zone around the flameless vent owing to the release of pressure and dust and gases.
• Backdraft dampers placed within the inlet ducting incorporate a mechanical barrier that remains open by the process airflow but swiftly closes from the pressure of an explosion. When closed, this barrier effectively prevents pressure and flame fronts from advancing further upstream in the process.
Conclusion
In industrial manufacturing and processing, controlling dust—especially combustible varieties—is a complex task. To tackle these challenges, implement a tailor-made, high-efficiency dust collection system equipped with appropriate explosion protection technology that adheres to NFPA standards. This strategic approach will help safeguard against risks to humans and prevent damage to both equipment and the facility.
This article originally appeared in the September 2024 issue of Occupational Health & Safety.
About the Author
Todd Willey is the Environmental, Health & Safety Quality Assurance Manager at Camfil Air Pollution Control, manufacturer of dust and fume collection equipment for challenging industrial applications. For more information call 800-479-6801, email [email protected] or visit camfilapc.com/.