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December 15, 2023

Follow These Tips for Bulk Bag Unloader Safety

Manufacturers around the world rely on flexible intermediate bulk containers, or FIBCs.

Also known as bulk bags or super sacks, FIBCs are essential for handling dry, flowable products such as granules, powder and crystalline materials. Demand for FIBCs is driven by industries including food production, pharmaceuticals, mining, and chemical manufacturing.

Safe handling is essential for realizing maximum value from bulk bags. A filled bag can weigh up to two tons or more, depending on density and materials involved. Although rare, an accident involving such a heavy bag can lead to severe injuries, along with regulatory penalties, workers’ compensation expenses and liability issues. 

From the earliest days of the industry (late 1960s), most bulk bag injuries have occurred during unloading or discharging operations. Accidents typically involved workers standing or reaching underneath an unsupported bag to untie the spout or cutting the bag with a knife for emptying. 

Unloading safety requires an understanding of common hazards involved in discharging bulk bags. Quality handling equipment should be designed to reduce the risk of an accident, and operators must follow FIBC safety guidelines throughout the unloading process.

Bulk Bag Unloading Safety Hazards

Here are some of the common safety hazards associated with emptying FIBCs:

  • Crush Injuries: This type of injury can happen when an operator stands or reaches underneath a bag to untie the spout. If a filled bag falls on someone, it is heavy enough to crush any body part that gets caught underneath. Falling bags have been known to cause severe fractures, amputations, and even deaths. 
  • Piercing Injuries: In some instances the bag is opened by lowering it onto a sharp piercing device which punctures the bottom and allows the product to flow out. Piercing devices are safer to use than reaching under the bag and cutting it with a knife. However, operators must use caution to avoid direct contact with the blade, as it can cause severe cuts and lacerations to hands or other body parts. 
  • Pinching Injuries: Bulk bag unloaders may be equipped with paddles or elongating mechanisms which facilitate efficient emptying. Operators must use caution to avoid pinch injuries to fingers and other areas that may come into contact with these components. Equipment that includes vibratory re-fluidizing systems offers a safe alternative to these mechanical pushing devices.
  • Dust Exposure: Many dry goods can be harmful when contacted by skin or inhaled. Unloading equipment should come with iris valves, glove boxes and other features to reduce human exposure to hazardous materials. And even non-toxic materials and dust should be contained or mitigated using dust collection, spout seals and similar features.
  • Static charge: Some dry materials may generate static electricity as they exit the bag. This creates a risk of electric shock, fire or even explosion in the right conditions. Proper grounding of Type C bags and unloading equipment is needed to discharge the electric current in these cases. 

Bulk Bag Unloader Safety Features

Drawing of two bulk bag unloaders side by sideFormPak designs heavy-duty super sack handling equipment made with a robust design and optional components for safe operations. Here are a few of the features we recommend for reducing the risk of accidents while unloading FIBCs.

Support Under the Bag   

One of the most common unloading accidents occurs when a suspended bag either falls or crushes the operator’s hands or arms as they attempt to untie the spout. The best preventive measure is to rest the bag on a sturdy support structure with an opening in the bottom. The operator then reaches their hand under the support to open the bag, reducing the risk of injury. This is not only the industry standard, but also required by OSHA. If audited or an injury occurs,  OSHA may issue a violation and fine.

Safe Opening & Discharge   

FormPak unloaders feature optional iris valves and access doors, which let the operator open the bag without having to step under it. The iris valve prevents material from exiting the bag while the operator unties the spout. An access door guards against exposure to the product as the bag discharges. 

Traditional unloaders often feature hinged paddles or bars promote the flow of material from the bag. These must be guarded from direct contact during use to prevent pinch injuries to operator hands and arms. As a safer alternative, FormPak unloaders feature a bag shaker with a heavy duty gyrator and rubber isolators to shake the support pan. This vibratory, re-fluidizer design ensures product flow without the pinch points of paddle style machines. Units that feature a piercing device should come with a safety gate that protects the operator from exposure during use. 

Dust Mitigation  

Personnel must be protected from dust inhalation and other exposure to harmful substances. Mechanical or pneumatic sealing keeps dust from flowing out of the bag spout while the operator unties it. In extreme cases, glove-box enclosures can be used. At minimum the access door is opened for untying, the spout is pinched close by the iris valve, then the door is closed and valve is opened to discharge the bag. 

Proper Grounding 

Bulk bags must be properly grounded to prevent static charges during unloading. The proper grounding method depends on the type of bag. For example: 

  • Type C bags are made with a carbon-infused grid to direct electrical charges to a grounding point.
  • Type D bags are made of a dissipative fabric that stays below the ignition threshold through sloughing or losing static charge at a constant rate.

Safe Bulk Bag Unloading Practices

Drawing of bulk bag unloader with full bag on the hopperOperators must carefully follow all proper handling procedures to ensure safe usage of FIBCs. Here are some best practices for increasing efficiency and reducing the risk of accidents. 

Make Sure FIBC Is Approved for the Product & Environment 

First and foremost, only use an FIBC that is approved for use with the product in question and the filling and emptying environment. Users should consult with manufacturers or suppliers to ensure that they are choosing the correct bag. Operators must strictly adhere to all manufacturer guidelines and comply with all regulatory and safety requirements. Working with a member of the Flexible Intermediate Bulk Container Association (FIBCA) can guarantee compliance with these requirements.

Use an FIBC Unloader with Proper Safety Features 

Choosing the right handling equipment is just as important as selecting the correct bag. You should only handle an FIBC using devices specifically designed for that purpose. Bulk bag unloaders should be rated for the capacity of the filled bag and have safety features to reduce the risk of injury. Operators must use the equipment in accordance with FIBCA safe handling guidelines and the manufacturer’s instructions. 

Use Proper Bulk Bag Handling Techniques  

Drawing of bulk bag unloader, overhead view

Proper handling methods will vary somewhat depending on the type of bag and unloader in use.

  • Hoist and trolley unloaders: The operator loads the bag loops onto the hoist, then pushes a button to lift the bag and lower it onto the support pan. Next, the operator closes the iris valve and opens the access door to untie the spout. Finally, the access door is closed and the iris valve is opened to discharge the product. All operations can be completed without the operator having to stand under the bag, and the access door prevents dust inhalation and skin contact with the product. 
  • Fork loaded unloader: The bag loops are loaded onto a fork adapter and placed onto the hopper pan using a fork lift. As with the hoist and trolley unloader, the operator closes the iris valve and opens the access door to untie the spout. The access door is closed and the iris valve opened to discharge the product. 

The Flexible Intermediate Bulk Container Association (FIBCA)  has published a set of guidelines to reduce the risk of injury and to ensure compliance with OSHA regulations. Here are some best practices for safe bulk bag unloading:

  • Never suspend an FIBC using less than all of the lift loops provided.
  • Never gather the lift loops together onto a single hook. 
  • Use a sling or other lifting device to keep the loops vertical if lifting with a single hook.
  • All forklift tines, crane hooks, adapters and other lifting devices must be free of sharp edges. 
  • Never allow anyone to stand or place any body part underneath a lifted FIBC.
  • Never exceed the safe working load or capacity limit of the bag. 

As noted above, choose a bag that is designed for the flammable or explosive environment to reduce the risk of a static charge. All conductive objects and materials must be properly grounded when discharging bags filled with flammable products.

At FormPak, we are proud to be the only manufacturer of bulk bag handling equipment that is a member of FIBCA, and have served on the board for more than 12 years. With over 130 member companies in over 25 countries, FIBCA is committed to safety in every phase of bulk bag usage. FormPak is a key contributor to the up-to-date FIBCA guidelines which serve as industry best practices. The guidelines have been translated into multiple languages to meet industry demand. 

Give us a call 800-936-7672 at or contact us online to learn more about our products.