Avoiding grain entrapment
April 8, 2014
In avoiding grain entrapment, more emphasis is now being placed on fall prevention versus fall protection, as well as new design parameters for grain bins.
As steel bins have gotten larger and the handling rates have increased, the number of reported grain entrapments and deaths in the U.S. have increased at an alarming rate, said Wayne Bauer, Star of the West Milling Co., Frankenmuth, Michigan, U.S. Bauer and William Harp, Safety and Technical Rescue Association (SATRA), Livonia, Michigan, U.S., discussed the topic during the Grain and Elevator Processing Society’s (GEAPS) Exchange in February.
From 2006-12, the U.S. averaged 16.3 deaths per year related to grain entrapments, a significant increase from 1964-83, when the average was under four deaths per year.
Bauer said there were 33 reported grain entrapments resulting in at least 13 deaths in 2013, compared to 19 entrapments and eight deaths in 2012.
“We expect these numbers to be even higher in 2014. We’ve had five fatalities in the last seven weeks. Given the condition of the crop harvested last year, we’re going to see more problems in 2014,” Bauer said. “The number just keeps going the wrong direction.”
Best management practices
In general, when someone has died as a result of a grain entrapment, they ignored or violated most of the best management practices involving entry into grain bins, Bauer said. These include:
Stay out if possible.
Never enter alone.
Never enter untrained.
Follow entry permit.
Shut down/lockout equipment.
In 1999, Bauer formed the Grain Entrapment Prevention Initiative, which developed the best management practices. The group has spread information through its website (www.grainentrapmentprevention.com), flyers and four safety symposiums.
The best way to prevent entrapment is to keep employees out of the bins if at all possible, Bauer said.
“It all starts with a better handle on grain conditioning, and using those aeration and temperature systems, making sure that grain is in condition,” he said.
The proper reclaim system, including discharge sump holes, sweep augers and service tunnels, is also important in ensuring bins are zero entry.
Training, particularly hands-on training, is essential, Bauer said. The ability to identify hazards, mitigate the hazards, how to use equipment and how to rescue someone, are not skill sets that can be covered with a 15-minute talk in the breakroom, he said.
“You need to get out in the bin and make sure you know how to use the equipment. Reinforce those skills every year,” Bauer said.
Share information with local emergency response teams so they understand where the rescue equipment is located, and how the elevator’s staff and the response team will work together should something happen.
A key point of the best management practices is securing a lifeline, which is also covered in OSHA standards. OSHA says the lifeline should be positioned, and of sufficient length, to prevent an employee from sinking further than waist deep in grain.
However, no one has ever defined how that can be accomplished, Bauer said. If someone standing outside a bin is holding a lifeline for a worker inside a bin, and the rope is jerked, they won’t be able to do much to secure the entrant.
“We need to get serious about this and challenge everybody to come up with the answers for their own situation,” he said.
That’s why, along with promoting the best management practices, the group has encouraged the grain industry to look at bin modifications to improve safety for workers.
Grain bin changes
The American Society of Agricultural and Biological Engineers (ASABE) since 2012 has been working to develop a new consensus standard called “X264 Design Parameters for New Grain Bin Entry.” ASABE along with steel bin companies have formed a committee that has been meeting regularly to discuss the standard.
The four basic areas that have been discussed include: increasing grain conditioning capabilities; larger access doors; restraint systems with secured lifelines and suitable anchors; and safer and more efficient reclaim systems.
A key concern is anchor points where workers can secure their bin entry lifeline, Bauer said. They should be designed to handle 2,000 pounds of force, for working on grain surface.
“We’re going to be doing a lot of testing to actually see what the forces are that these systems are seeing in various applications,” Bauer said. “We would like to see any anchor points to handle a minimum of 1,800 to 2,000 pounds of force.”
Virtually all of the steel bin manufacturers are developing anchor systems. Sioux Steel has developed an anchor support with a shackle on it that can be fastened at the top of an access hole; the lifeline is attached to the shackle.
Global Industries has developed a system that uses a U-bolt in conjunction with a stiffener at the eave and near the compression ring at the top of the bin. Star of the West worked with SATRA to create the knot-passing-pulleys that can secure a lifeline and keep the slack out of the line, Bauer said.
“Walk around your facility and ask yourself: If you had a serious situation and you needed to get someone back down to the ground in a hurry, do you have the anchor points that you can tie your bin entry lifeline to?” he said. “Discard the idea of tying off on air ducts, ladder rungs, or electrical conduits.”
Other design changes being discussed include the design of access doors so that they are large, better positioned at the top and sides of a bin. This gives operators better entry points to maneuver and potential rescue teams more space to extricate victims.
Adequate work platforms are needed that conform to ANSI standards. Use of simple 18-inch steps should be discouraged when the distance is more than 4 feet off the ground.
Reclaim systems are being examined, including the size and spacing of discharge sump holes. Often, a reclaim system stops unloading product because clumps of grain are not entering the sump, a sweep auger has stopped functioning, grain is stuck against the bin wall, or a cavity with a bridge over it has formed.
Bauer said the group will look at lockout/tagout near entry points into the bins, and is also looking at aeration systems with an emphasis on exhaust systems. Ideally, the grain should be kept in the best condition possible to limit the need to enter the bin. But the grain is under attack by moisture insects, foreign material, condensation and poor quality.
Other areas being reviewed include signage and labeling; ladders; and providing better construction and operating manuals.
Alterations to the grain bins go a long way in preventing grain entrapment by providing a means for fall prevention as well as work positioning. These are perhaps new terms for operators, who have in the past focused on fall protection, SATRA’s Harp said.
Fall prevention stops a user from falling any distance. The system includes a body harness along with an anchorage, connectors and other necessary equipment. The other component typically includes a lanyard and may also include a lifeline, Harp said.
In comparison, fall protection protects a worker from the impact forces if they fall. The system is designed to stop employees from falling off, onto or through work levels and to protect employees from being struck by falling objects.
“When you fall, it’s like when a dog hits the end of their chain. We don’t want that to happen to our employees; we want to avoid all of that. That’s where we get into work positioning and fall prevention,” Harp said. “I want you to think of it as two chapters: Fall protection and all of the techniques for fall prevention/work positioning.”
Harp demonstrated some of these techniques during the GEAPS presentation, including a bin-entry-kit. The kit includes an anchorage strap or piece of 1-inch webbing attached to an anchor; connectors (carabiners); a lifeline; tandem prusiks; and a prusik minding pulley.
A prusik wraps around the lifeline rope and can slide along it. When a load is applied, the prusik locks, preventing the person on the end of the line from falling. One prusik can hold 2,200 pounds, Harp said, so two will nearly reach the 5,000 pounds being asked of the anchor.
“The lifeline has to be attached to a suitable anchor. Envision if you had two or three people that needed to be fully supported, how strong that anchor needs to be,” he said. “That’s why we’re talking with bin manufacturers to deliver anchors that are already installed so you’re not trying to ad lib things.”
During a bin entry, the person staying outside of the bin can mind the prusiks, letting rope out little by little.
“As he enters the bin, I’m pulling up the slack. You don’t want more than two feet of slack,” Harp said. “As he climbs into the bin, I’m managing the slack and we’re working together and communicating. If the ladder breaks, the prusiks will pop out of my hand, lock on the rope and the anchor takes the weight.”
The system can be reversed so the worker can have the prusiks on his end and have all the control. A prusik costs under $9, is easy to use and is very durable, Harp said. In order for this system to be safe, there cannot be more than two feet of slack, because there is no force attenuation, no rip stop or lanyard that is going to give.
For a side entry, even with a prusik and anchor, a worker could still sink into the grain. In that situation, one possible solution is the knot-passing-pulley at the very peak of the bin.
“In some of these commercial facilities where bins are 100-foot in diameter, and an employee is in the middle of a bin, side entry with a lifeline isn’t going to do any good,” Harp said. “With an overhead pulley, the employee can manage how much slack is in that lifeline.”
The same system can be used for work positioning. Many times when industrial workers fall, they are wearing a harness and lanyard, but they never hooked it up, perhaps because they were fatigued or distracted. But with work positioning lanyards, there is better compliance, Harp said, because the individual using it learns to depend on it.
“If they’re working on the top of a leg, the find an appropriate attachment, take the slack out, and they get that tactile feedback that they are secure,” he said. “These techniques are used when you are the attendant around a confined space entry, when you’re going into a bin, working in grain, any of those things where you are positioning someone.”