Connecting with Safer Rigging Techniques
Whenever heavy objects need to be lifted on a worksite, a significant amount of planning and decision-making making is required for a successful move. Much of the attention is naturally focused on the crane, hoist, or other device that will make the lift, to verify that it has sufficient capacity.
Something that’s every bit as important, but rarely given as much thought by the average worker, is the role of proper rigging in safe load handling.
Several years ago, OSHA tightened crane regulations following a series of high-profile crane accidents. Part of that change involved tightening the rules related to rigging. After all, if the rigging is inadequate or fails, there usually isn’t enough time to warn workers in the area. In addition, when heavy loads fall, even if injuries aren’t involved, the physical damage can be catastrophic. The lifting equipment may also suffer costly damage.
Because proper rigging is so important, it’s prudent for crews that are directly involved with lifts, or that work in the immediate area, to become familiar with the correct procedures for rigging and safety issues that must be considered when lifting large and heavy objects.
The new rules spell out specific responsibilities for workers who handle rigging on the jobsite. They need to receive training that outlines the potential hazards of the type of rigging, and they must be qualified to comply with the procedures that are appropriate for the task. In addition, they have to be aware of the environment and its effect upon the lift, such as knowing whether a surface is solid and level enough for a crane to perform the lift safely.
Riggers must be thoroughly familiar with the equipment they are using, including knowledge of the capacities of rigging gear and the hoist or crane. They need to know the correct techniques for the situation and ensure that the location where the load will be set is free of obstructions or other potential hazards. They should also be knowledgeable enough to recognize developing problems and have the authority to stop the task and take corrective action if any aspect of the lift becomes unsafe.
When workers need to provide rigging, they must wear clothing and personal protective equipment (PPE) that’s appropriate for the conditions. Clothing should protect the workers from contact with equipment or surfaces that could injure them. Baggy or loose clothing could be snagged during the lift, so shirts and other items should be properly tucked in. Steel-toed safety shoes and leather gloves are normally required for working with rigging equipment, and hardhats and eye protection can prevent injuries from swinging hooks or dropped loads.
In addition to ensuring that the ground is level and solid, and that there are no obstructions or items that may be knocked aside, riggers need to review the work area for other potential hazards. One of the biggest dangers when working with cranes is coming into contact with energized power lines or electrical equipment, which can cause burns and electrocution. Another potential hazard is moving machinery. If there is a possibility that a boom or sling could come into contact with one of these hazards, the crane or hoist operator and the rigger should work together to identify the safest way to proceed.
Weather conditions may also factor into the lift. Snow, ice, or rainwater may make the work area slippery. If there is lightning in the area, do not operate the crane until conditions improve. Because lightning can travel several miles from an actual storm cell, remember the familiar warning “when thunder roars, go indoors” and stop work at the first rumble of thunder.
The rigger is also responsible for thoroughly inspecting the condition and function of the rigging equipment. In addition to slings, chains, and pulleys, that includes examining hooks and pad eyes for any damage or distortion. For example, if a hook is twisted by more than 10 degrees, it probably isn’t safe for use. If a pad eye isn’t properly attached or is highly corroded, it should be repaired before the lift begins.
In nearly every case, the safest approach is to use a sling, rather than attach the crane or hoist cable, chain, or rope directly to the load. There are many different types of slings, and the right type for the task depends upon a variety of factors, such as the size and shape of the load, environmental conditions such as weather, and the potential for damaging the surface of the load.
No matter which type of sling is being used, examine it closely to ensure that there is no damage that would impair its integrity. Broken wires on a wire sling, corrosion at connections, or worn material on a fabric or synthetic sling can all increase likelihood that the sling will fail.
Choose a hitch
The type of hitch you use will depend upon the load, its weight, and the nature of the lift. Most often, workers use a basket hitch, in which the sling goes around the object to be lifted and the sling’s ends are placed over the hook. A choker hitch is similar to the “choke” collar some people use when training dogs. After placing the sling around the object, one end is fed through the end of the other to create a tight hold. The third type, the vertical hitch, is usually the best choice when the load has some type of attachment designed for lifting, such as a pad eye or eyebolt. The sling is connected to the attachments and to the hook on the hoist or crane.
If the load is large enough or the weight distribution makes lifting it more challenging than normal, multiple slings may be used. Some loads may need to be padded to protect the load from damage caused by the sling, such as when a wood or soft metal object is lifted using a wire sling.
Lifting and moving
When the load is ready to be lifted, the hoist or crane operator and the rigger will normally communicate through hand signals. It’s important that both parties use standard signals to avoid miscommunication.
It’s also important to remember that both hoists and cranes are designed to lift loads vertically, not at angles. Trying to lift at an angle can damage or even topple a crane, and cause the load to swing dangerously.
Loads should be moved slowly and carefully to minimize unwanted motion, such as spinning. Attaching rope taglines can give workers a way to steady and properly position the load before it is set down. Riggers and other workers should act as additional sets of eyes for the crane operator to ensure that he doesn’t strike any obstructions.
At no time should workers be underneath a load, whether that’s by walking under it or having the crane operator move it above them. In addition, if there’s a need to stop before the load has reached the destination, it must not be left unattended while in a raised position. Instead, it should be lowered to a safe location until it’s ready to be moved to its destination.
Once there, the operator should lower the load slowly and stop several inches before placing the load on the ground or other destination. That way, the rigger and other workers can verify that it is positioned correctly and that there are no obstructions or debris in its path. Once the load has been fully lowered, the slings should be removed from the hook. The operator can then raise the crane or hoist to ensure that workers cannot bump into it.
After removing the slings from the load, inspect them again, and discard them if there is any damage. If they are still in good shape, they should be stored properly so they’ll be ready for use the next time they are needed.