In 2018, a Houston jury awarded $39.7 million to a man injured in a 2014 dust explosion at a Georgia Pacific plant in Corrigan, Texas. Two people were killed and four injured after a fire in a dust collection system led to a massive explosion.
Cases like this illustrate the danger posed by dust particles in industrial settings. Companies must invest in extensive dust control measures and equipment to protect employees and to reduce the cost of fines, property damage and lawsuits.
This is especially important when working with dry bulk goods such as those used in food, pharmaceuticals, chemical processing and other industries. These types of products are commonly stored and transported in flexible intermediate bulk containers (FIBCs), also known as Super Sacks®, bulk bags or big bags.
The Risk of Dust Explosion
Combustible dusts are fine particles that present an explosion hazard when suspended in the air. Other industries that work with explosible dust include agriculture, furniture, textiles, fossil fuel power generation, metal working and recycling. Companies are responsible for determining whether this hazard is present in their operations and for taking steps to reduce the risk.
Materials that can cause an explosion in dust form include food ingredients such as sugar, flour and other types of grain. Combustible dusts may also be produced from materials as diverse as plastics, wood, pesticides, and even some metals including aluminum, chromium and zinc.
Lowering the Risk of a Dust Explosion
Dust control presents a major challenge to plants that deal with powdered products on a regular basis. Not surprisingly, it is also subject to stringent regulations at the federal and state levels. OSHA hazard assessments, for instance, consider materials handled, operations performed and byproducts generated. Inspectors also take a close look at specific spaces where operations occur and all potential ignition sources that are present.
A proactive dust control plan is essential for avoiding fines and for reducing the risk of accidents. Regular internal inspections, testing, housekeeping and control policies are a must, along with proper dust collection methods and filtering systems. Other best practices include choosing surfaces that minimize dust accumulation and using cleaning methods that do not generate dust clouds.
Ignition control measures should include steps to minimize and/or dissipate static electricity, including bonding conductive materials and equipment to the ground. Throughout the operations process, managers should invest in equipment built to safely handle combustible materials. Equipment should be designed to minimize direct exposure to employees by preventing dust from escaping into work areas.
Bulk Bag Design & Handling Combustible Dust
The Flexible Intermediate Bulk Container Association (FIBCA) recommends bulk bag design features that protect against static electricity. The static discharge hazard is determined by different factors including bag materials and handling equipment used.
- Type B bags are made with insulated fabric intended to reduce the risk of energetic sparks or propagating brush discharges which could ignite airborne dust particles.
- Type C bags include interconnected conductive threads woven into the bag to prevent incendiary sparks, brush discharges and propagating brush discharges. This type of bag must be electrically ground when filling and emptying.
- Type D bags are made from a static protective fabric that dissipates static electricity without a grounding wire. Like Type C bags, Type D is also intended to prevent brush discharges, propagating brush discharges and incendiary sparks.
Bulk Bag Handling Equipment
Depending on the type of FIBC in use, bag handling equipment must ground the bag to prevent dust exposure and mitigate the risk of static shock. The operator must also be grounded when working with combustible materials in groundable bags.
Selecting the right equipment reduces the risk of dust explosions or static shock as material flows into or out of the bag. For example, Type C bags must be grounded during filling and discharge. A grounding system clamp helps to direct static electricity from the bag to a locally verified ground source, reducing the risk of electric shock or fire.
Operators must also be protected from dust inhalation as bags are being filled or emptied. Proper equipment eliminates unsafe maneuvers such as holding spouts in awkward positions or using inferior sealing devices such as bungee cords. For example, a pneumatic or mechanical sealing system lets the operator close off the spout prior to opening the bag. An insolation valve, such as an iris valve, permits the operator untie bag and then close access door before flowing the material.
Bulk bag handling equipment that helps with dust control in your operations? Reach out to FormPak today for more information!
