Grain Bin Safety - Grain Engulfment & Entrapment
Did You Know...
- Flowing grain behaves like quicksand.
- In 4 seconds, an adult can sink kneedeep in the suction of flowing grain. At this point, he or she can’t free themselves without help.
- An adult can be completely buried (engulfed) in 20 seconds. Most engulfed victims do not survive.
Grain engulfment and entrapment incidents are on the rise in recent years due to record harvests, larger storage facilities, and equipment that moves grain at faster rates than ever.
What Are The Risks?
Grain engulfment has been a recognized hazard for decades. Yet both experienced and inexperienced workers continue to underestimate the deadly risks ssociated with the speed and force of flowing or shifting grain.
Anyone who enters a storage structure containing grain, or who climbs onto an outdoor grain storage pile, is at risk of being entrapped or engulfed in grain. Fatalities have occurred in as little as a few feet of grain.
Roughly half of known entrapments occur on farms, and half occur in commercial facilities. Most entrapment and engulfment events occur because workers enter a bin or storage structure to check on condition of grain or to address problems with grain flow due to spoiled grain or equipment malfunction. But other scenarios present risks even when grain is not being unloaded from the structure.
Dangerous Scenarios
Flowing grain
Around 80 percent of reported engulfments involve a person inside a bin or storage structure when grain-unloading equipment is running.
As unloading conveyors or augers remove grain through the bottom outlet, a funnelshaped flow develops on the surface of the grain. Anyone standing on the surface while grain is being removed from below is at risk of being rapidly pulled down toward the outlet in the column of flowing grain. Submersion takes only seconds and once it begins, the pressure and friction forces of grain on the body are virtually impossible for victim to overcome.
Bridged Grain
Spoiled or “out-of-condition” grain clumps together and can develop a crust on the top surface. This crust appears solid, but it is unstable and may hide open voids below that develop as grain is removed. Bridged grain can collapse under a person’s weight, resulting in the victim being buried by falling and shifting grain.
Vertical Grain Wall Avalanche
Spoiled grain can form a clumped mass that adheres to the vertical wall of a bin. Entering a bin to dislodge a vertical wall of grain that is higher than the victim is dangerous because the grain wall can suddenly break loose and fall like an avalanche, burying or injuring the victim.
Grain Vacuums
Some fatal engulfments have occurred while individuals were using grain vacuums to remove grain from bins. When the grain vacuum nozzle is placed below the grain surface, a funnel flow of grain develops as grain is sucked into the tube. An operator can be pulled into the downward flow of grain if this nozzle is released or becomes buried below the grain surface near the operator’s feet.
If the operator falls or struggles for position, his movements can trigger an avalanche of grain if the slope of grain (“angle of repose”) is steep.
Prevent Engulfments
The best ways to prevent engulfment incidents are to eliminate the reasons for entering a bin in the first place, and to restrict unauthorized access by youth or other individuals who may be unaware of hazards.
Manage Grain To Prevent Spoilage
The most common reason victims enter bins is to address problems associated with spoiled grain. Spoiled grain forms solid masses, crusts, and horizontal grain bridges and vertical grain walls that can collapse. Spoiled grain plugs augers and conveyors, necessitating entry into the structure to unplug or free the clogged equipment.
By maintaining proper climate and moisture levels within your bin, spoilage can be prevented.
Work From Outside The Bin
If clumps or crusts develop in the grain, use a pole from outside the bin to probe or knock the clump free.
Restrict Access
Post signage and lock access doors so unauthorized persons, bystanders, and youth cannot enter.
Plan Ahead
Provide Training
Training should include recognizing grain quality problems, entry procedures, use of safety equipment, and emergency response, before allowing access to a bin or storage structure. Training should be provided at regular intervals, not just upon hiring or once a year.
Emergency Rescue Plan
The plan should include having cell phones on site, emergency numbers posted for local emergency responders trained in bin rescue, and prevention of untrained “would-be rescuers” who could increase grain pressure on a victim or even become engulfed themselves.
Shut Down All Equipment
This includes turnheads, reclaim conveyors, augers, etc. If mechanical and pneumatic grain moving equipment cannot be locked out, do not enter.
Evaluate the Atmosphere
Use a gas meter to check for adequate oxygen content in the bin and the presence of toxic gases like carbon monoxide (which can be present if there is combustion or smoldering grain), fumigants, or excessive carbon dioxide. If grain is out of condition, or the atmosphere conditions cannot be determined, do not enter.
Visually Inspect
Never enter a bin:
- Where the upper level of grain along the wall is above the entrant’s position inside
- If grain is hung up on a side wall
- If the angle of stored grain exceeds the angle of repose
Never Enter Alone
Two outside observers must be present to monitor entry and assist by regulating a lifeline tether. One attendant must maintain constant visual monitoring of the entrant and have a system of communication worked out before entry (hand signals).
Use Fall Restraint Equipment
This consists of a full body harness attached to an anchored line, and limits the distance the entrant can drop or fall in the event that grain shifts or a grain bridge collapses beneath the entrant.
Trained Only
Never allow youth under the age of 16 or other that have not been trained in grain bin safety produces to enter grain storage structures.
For more information on grain bin safety go to www.grainsafety.org.
