First-responders called to a grain bin entrapment should expect the unexpected because no two situations are the same. The frequency of grain entrapments has steadily increased over the past decade as a result of record grain yields, long time in storage, larger storage tanks, and fast unloading equipment.
This article discusses grain entrapment prevention, preparation, and rescue strategies. Safe grain handling practices, confined space entry procedures, and grain rescue training can give rescuers a leg-up during an emergency. Entrants may not realize that taking shortcuts can lead to disastrous results. It is important for rural communities and grain handling facilities to understand the dangers of working with grain and take precautions when entering a grain storage structure. When accidents happen, emergency personnel must act quickly and efficiently to prevent a grain extrication rescue from becoming a recovery. Your department can be proactive in preventing grain entrapment by spreading grain safety awareness and adding a grain rescue device to your equipment.
What causes grain entrapment?
The grain handling industry is a high hazard industry; workers are exposed to dangers such as grain dust explosions, grain entrapments, falls, toxic gasses, and crushes and amputations from grain handling equipment. Of these dangers, grain entrapment is the most frequent agricultural accident. Farmers and grain elevator employees enter bins frequently to monitor grain quality, take inventory, and clean bins. 2010 was a record year for grain entrapments with 59 reported incidents and 26 fatalities. In 2013, grain entrapments accounted for 49% of all agricultural incidents in the United States. Of these 33 entrapments, 13 resulted in fatalities.
Emergency crews are a crucial part of a successful grain extrication because the process requires skill, resources, and trained manpower that understands the stresses that grain entrapment puts on the human body. Grain is heavy; corn weighs 70 pounds per square foot and soy beans weigh 75 pounds per square foot. The grain’s weight and frictional characteristics make it impossible to simply pull a victim out of grain. For example, it would require 325 pounds of force to pull a 165 lb. victim from 3 feet of grain. The human body can’t handle that amount of force and the victim would be injured. Asphyxiation is the leading cause of grain entrapment deaths. Even considerably small grain storage, such as a grain cart, contains enough grain to exert extreme pressure on a victim’s chest and inhibit breathing. The enveloping flow of grain will enter any void it can, including a victim’s mouth and nose.
The nature of grain in storage is a contributing factor to the large number of incidents. Wet grain is stored in a holding tank and then through a grain drier before it is transferred to a large storage bin. The quality of grain put in storage must be monitored; moisture levels, toxin levels, percentage of foreign material, and temperature are important attributes of stored grain. High-moisture or low-quality grain can go out of condition, which leads to spoiled, sticky product that becomes hard and doesn’t flow evenly when unloaded. Workers will enter storage bins to sample grain, check bin level, or investigate why grain is not unloading properly, which may put them in a perilous situation.
Grain entrapments happen in three ways: engulfment in flowing grain, collapse of a grain bridge, and collapse of a vertical grain wall. As grain is unloaded, it flows from the top layer down a center column to the auger at the bottom of the bin, creating a cyclone effect that quickly engulfs a victim. To put it in perspective, modern bin unloading augers move up to 5,000 bushels of grain an hour, equivalent to 1.40 bushels per second. A 6 foot tall worker displaces approximately 9.38 bushels of grain. If the worker is caught in the grain flow, he could be engulfed in only 7 seconds. Some entrapments in flowing grain occur when the entrant wants to speed up the flow of grain by walking down it. In these instances, the entrant could lose their footing and become engulfed by the moving grain. (Walking down grain is a common practice, but it is prohibited by OSHA standards.) Spoiled grain creates hazardous grain bridges and vertical grain walls that may collapse and engulf an entrant.
A grain bridge is formed by the hardened surface layer of stored grain exposed to air, but conceals a void beneath the surface. The bridge can collapse under the weight of a worker walking in the grain, engulfing him instantly. Alternatively, vertical grain walls are formed when spoiled grain cakes to the side of the bin. If a worker tries to knock down the grain, it may cause an avalanche and trap the worker within moments.
Preventing grain entrapment through confined space entry procedures
Despite the dangers that exist inside a grain bin, the risks are often overlooked. Employer negligence, non-compliance with standards, and poor safety practices are a frequent cause of grain bin entrapments. The USA’s regulatory employee safety agency (OSHA) classifies a grain bin as a permit-required confined space; it has limited means of entry and exit, an internal configuration that poses an entrapment hazard, and/or a potentially toxic atmosphere. OSHA Standards 1910.146: Permit required Confined Spaces and 1910.272: Grain Handling Facilities outline the required protocol of which commercial grain facilities must be in compliance, or run the risk of judiciary and monetary punishment.
Although private farms are exempt from OSHA standards, farmers should follow the same guidelines to prevent entrapment in their grain bins; roughly 50% of reported grain entrapments have occurred at farms that are exempt from OSHA standards. Grain entrapment can be prevented if entrants follow confined space entry protocol and use common sense.
Confined Space Entry Permits
A confined space entry permit is an all-inclusive form that summarizes the tasks that should be performed before, during, and after a person enters a grain bin. Every commercial facility is required to have blank confined space entry permits available and completed permits kept on site after work is finished. Templates for confined space entry permits can be found online.
Lock-out / Tag-out Program
Locking-out the power supply to the bin will ensure that no one but the entrant can turn on the bin equipment, such as the load-out auger or bin sweep, which could move grain in the bin and cause an entrapment. Tagging the locked out bin alerts others that there is a worker inside the bin. Lock-out tag-out systems are a simple and cost effective way to prevent grain entrapment.
Monitor Air Quality
Air quality checks are vital to grain bin entry; the interior atmosphere has potential to be toxic due to spoiled grain, insecticides, and other oxygen-displacing elements. Rescuers or workers should slowly lower a calibrated air monitor inside to check air quality before entering a grain bin. Entrants must keep a four gas air monitor on their person while in the bin, as well as periodically run an air check and report levels on the permit.
Commercial facilities must provide employees with personal protective equipment and proper PPE training. Harnesses and life lines prevent falls and keep the entrant from being sucked under flowing grain. Respiratory protection should also be worn to protect victim from inhaling dust and mold spores.
An observer, equipped and ready to provide assistance or call for help, must be stationed outside of the grain bin and oversee that the entrant safely performs work.
Grain entrapment rescue
Grain bin rescues will test the skill and resources of responding emergency agencies. Emergency personnel must be trained and prepared for all aspects of grain bin rescues, including high-angle, bin cutting, auger entanglement, and grain extrication. Cutting edge grain rescue equipment used along with modern grain rescue strategies can expedite a rescue. Preplanning and training with a grain extrication device are necessary to prepare your department for a grain bin rescue.
Familiarize your department with bulk grain storage in the area; whether it is a large commercial facility or a rural on-farm bin, a lot can be learned from seeing grain storage first hand. Identify power supplies and back-up generators to expedite a lock-out/tag-out program. Ask the facility manager for their emergency action plan and a map of the facility for reference. Take the bin structure into consideration as well; bin manufacturer, material, sheet thickness, bolt patterns, and location of stiffeners are important for the bin cutting team. Check ladder integrity, bin opening size, location of anchor points for life lines, and structures that may hinder bin entry and exit. A successful grain bin rescue requires the collaboration of a large number of personnel, and preplanning helps alleviate the complications that may arise.
Grain Extrication Strategies
This section serves only as a summary and is not thorough grain rescue training.
A successful grain bin rescue requires a tremendous effort from the rescue team inside the bin in charge of extricating the victim. The characteristics of grain make it very difficult to walk; rescuers’ movement may shift grain onto the victim. The interior environment of the bin is very dark and dusty, making it difficult to see. The temperature inside a grain bin can reach extremes. The bin opening may be too small for rescue equipment. Despite the urgency to free the victim as fast as possible, hastiness may further endanger him. The best preparation is to devise a specific strategy for each rescue, using tactics developed from hands-on grain rescue training with a grain rescue tube. The team in charge of grain extrication should be thoroughly trained and practiced in grain extrication.
Grain rescue tubes are a life-saving tool used in grain rescues. Before rescue tubes were a readily available product, rescuers struggled with the issue of grain constantly flowing back around the victim after they shoveled it out of the way; plywood and back boards were often used as a desperate attempt to hold grain back. Grain rescue tubes consist of panels connected together to surround the victim and are pressed deep in the grain, relieving pressure on the victim and serving as a retaining wall so that grain can be removed from around the victim. Rescue tubes differ in construction, connectors, price, and driving method.
The Great Wall of Rescue, a grain rescue tube manufactured in Lanark, Illinois, can adapt to suit grain rescue scenarios; there is no limit on the number of panels that can be combined. Aluminum panels are joined via anodized ball and socket connectors to surround the victim. Neighboring departments may combine Great Wall systems and expand their rescue abilities. Consider building a larger tube to surround a rescuer tending to the victim, or using Great Wall panels to form an arched wall around the rescue to divert shifting grain. Individual panels are driven into the grain, one by one, by the rescuer stepping onto a hinged “step” that hooks onto the top of a panel. As the panels are driven deeper, grain is removed from around the victim using buckets or a grain auger until he can climb or be lifted out.
A grain entrapment rescue will test the skills and resources of the responding agencies, but there are ways to prepare: understand the basics of safe grain handling, promote confined space entry procedures, and train, train, train hands-on with a grain rescue tube. Simple preventative measures like lock-out tag-out can be an asset to large commercial facilities and small private farms. The value of preventing one grain entrapment outweighs any aggravation from taking cautious steps.
For further information, go to www.greatwallofrescue.com