Preventing Fires and Explosions with Industrial Magnets

Manufacturing facilities face a constant battle against hazards, with fire and explosion risks being particularly daunting. In industries handling powders and bulk solids, combustible dust is a significant threat. When hovering in the air, these fine dusts can ignite, risking human safety and causing substantial economic loss. A critical factor contributing to the ignition of these incidents is the presence of ferrous contaminants in product flow. Magnets, strategically deployed in dry bulk processing, offer a powerful solution by effectively removing these ignition sources, reducing the risk of catastrophic events.

Understanding the Threat

OSHA defines combustible dust as a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in the air or another oxidizing medium over a range of concentrations. To put it simply, combustible dust is any fine, solid material that can burn or explode when mixed with air.

The conditions and environment where these particles are present play a large role in leading to disaster. According to the OSHA Hazard Communication Guidance for Combustible Dusts Guide, there are five elements that must be present for a dust explosion to occur, which are often referred to as “The Dust Explosion Pentagon.” These include: 1. Combustible dust (fuel); 2. Ignition source (heat or spark); 3. Oxygen in air (oxidizer); 4. Dispersion of dust particles in sufficient quantity and concentration; 5. Confinement of the dust cloud. The first three elements are what are needed for a fire to take place, while all five need to be present for the explosion.

Many industries generate significant amounts of dust during processing operations, which can subsequently become suspended and gather in the air. Several industries pose a significant risk for fires and explosions. Industries such as food processing, woodworking, metal processing, synthetic manufacturing, and recycling generate significant amounts of fine particles during their operations. This results in an increased presence of dust in the air, creating a potentially explosive combination.

Metal is present in almost all stages of the manufacturing processes. Whether it is the containers the product travels in, the machines they run through, encountering packaging items such as screws or staples, metal is everywhere. When ferrous metal contaminates product flows, those pieces, depending on material, can create a spark or produce enough heat generation from friction to ignite a fire and/or explosion.

“Magnets are used in the effort to eliminate fires and explosions in dry bulk handling systems,” said Dan Allore, director of engineering, Industrial Magnetics. “The metal items in a dusty product stream can cause a spark which could lead to fire or explosion. By magnetically removing the metal the risk is removed from the system.”

IMI’s extended length plate magnet is built to capture ferrous material at higher rates of speed in steep chutes (IMI).

The Role of Magnets

Dry bulk goods are unprocessed raw materials managed in large quantities. They form the components of numerous industries that were previously mentioned. Sectors such as food processing and production, woodworking, metals, synthetic manufacturing, and recycling operations all produce dry, bulk products that require sorting and purification. Additionally, these industries listed are also ones that generate large quantities of combustible dust, leading to greater risk during manufacturing operations.

The role of magnets within the dry bulk processing is to pull, trap, and capture metal within bulk product flow. As ferrous metal passes through the magnetic field, the magnets hold the contaminants to the work area. This removal of the metal contaminants is removing risk from dry bulk processes. By eliminating these components that can generate heat and spark, potentially causing fires and explosions, you not only ensure the purity of the end product, but you are also guaranteeing the safety of your equipment, facilities, and employees.

Tube magnets arranged in a grate to capture the maximum quantity of metals passing through (IMI)

Different types of product flows require different magnets. What type of goods are being processed and under what conditions determines what magnet is best suited for the application. When dealing with difficult flowing products in high-flow rate scenarios, a drawer-in-housing is often preferred. This equipment is a series of round magnetic tubes set in offset rows. This setting of the tubes forces the product to cascade and have intimate contact with each tube in the housing. Because of the intimate contact made with each tube, this is the best way to separate ferrous metal from the product flow. The round tubes inherently help secure the ferrous product to the magnet as the flow rushes past it. The metal contaminants will migrate to the bottom of the tube into a safe no-flow area.

A plate magnet gets mounted on the bottom of a chute, so the product flows past the magnet. These are ideal for capturing ferrous metal out of high-velocity product flow, protecting downstream processing equipment and product purity. The plate magnet's design--including a spout face, step, or ramp--prevents captured product from washing away as the product flows past at high speeds.

Team members from IMI doing routine maintenance on their yearly audits for a customer with powdered material (IMI)

Prevention of fires and explosions is paramount and as outlined in this piece: magnets play a pivotal role in that prevention. Industrial magnets can also be designed to mitigate the consequences of fires or explosions. Engineers at industrial magnet manufacturers possess the expertise to design magnets capable of withstanding extreme conditions, including those where explosion hazards are present. These custom designs--such as pressure shock-resistant magnets--are engineered to prevent catastrophic failure and shrapnel dispersion in the event of an explosion. This means your equipment is protected from secondary damage caused by the magnet itself, ensuring overall system integrity.

Conclusion

Understanding the consequences of combustible dust fires and explosions are seen every day and knowing the state of your own risk is critical. If your operations align with OSHA's guidelines for combustible dust, your facility is likely at risk.

Integrating magnets into dry bulk processing systems offers a solution for eliminating the ignition source of these catastrophes while also purifying your product flow. The removal of metal contamination also propels businesses to protect their workforce and safeguard valuable assets. Investing in magnet equipment is not merely a compliance measure; it is a strategic decision that prioritizes safety, operational efficiency, and long-term sustainability.

Emma Vondra is marketing content specialist, Industrial Magnetics Inc. (Boyne City, MI). For more information, call 800-662-4638 or visit www.magnetics.com.