BY DON FRANK
If victims are trapped in any type of vehicle, including buses and tractor trailers, or in a building that has collapsed during an earthquake or tornado disaster, it is the responsibility of rescuers to remove debris and objects to gain access to them in a safe manner without causing further injuries or harm.
In such emergencies you may be using hand equipment such as Come-alongs, crowbars, high-lift jacks, shoring, cribbing, and chains. Other useful equipment may include block and tackle, cutting tools, welding equipment, lifting tools, and rigging A-frames. Cranes may be needed to remove the debris to access the victims.
I have designed and built a chain-shortening device (photo 1) that eliminates excess chain. This device is made with two 3/8-inch-grade 70 clevis grab hooks, two pins, and three links of 3/8-inch-grade 70 high-test chain, all rated at 6,600 pounds of pulling force. The grab hooks and rescue chain should be of high quality. The chain-shortening device and the rescue chain used also should be of the same diameter so that the rescue chain fits snugly in the throat of the hooks.
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The hooks are fastened to each end of the chain. The device is designed to be used with 3/8-inch chain and hand tools only-it is not intended to be used with hydraulic-powered rescue equipment. Hydraulic tools produce pulling forces anywhere from 6,000 pounds up to 20,000 pounds; only chains that are rated for those tools should be used with them.
The grab hook in the chain-shortening device is designed to be hooked back onto the chain, or onto a link providing a hold on the chain link, properly seated in the throat of the grab hook for pulling (photo 2).
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To prevent injury when handling hooks and chains, avoid conditions that damage and reduce the capacity of the hook and chain, including back load (photo 3), side-load hook (photo 4), tip-load hook (photo 5), or shortening a chain with knots or by twisting (photo 6).
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Also, do not allow the chain to be subjected to sudden forces, such as slipping and then sudden stopping (known as a shock or shock load). Do not exceed the working load limit of the chain or hook.
There are many uses for the chain-shortening device. Such a device can come in handy when you are using a vehicle for an anchor point and you are unable to turn the grab hook through the hole to be hooked back onto the chain (photo 7). Also, in situations in which there is too much chain for the work you are doing, you can easily disable excess links from the middle of the chain using the device (Photos 8, 9). This is particularly effective for activities involving pulling (photo 10) or lifting (photos 11, 12) heavy objects.
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DON FRANK is a 27-year veteran of the fire service and a firefighter with the Defense Distribution Depot, San Joaquin, California (DDJC), and the Fire Department of the Defense Logistics Agency, Tracy, California. He has served as a rescue firefighter with the Robins Air Force Base Fire Department in Georgia, and with the Springlake (CA) Fire Protection District. He is an instructor in all phases of aircraft emergency firefighting, confined space, high-angle rescue, and building collapse operations. A nationally certified fire instructor III, he holds fire officer certifications from California and the U.S. Department of Defense.
