This training session focuses on safe rigging for crane and derrick operations at construction sites. A critical job for the safety of any crane or

Transcription

1 This training session focuses on safe rigging for crane and derrick operations at construction sites. A critical job for the safety of any crane or derrick operation is rigging the load. A poor rigging job can lead to injured workers, property damage, or other serious consequences. Rigging is the most timeconsuming of any crane operation and represents the greatest hazard potential. In this training session we ll cover the fundamentals of rigging cranes and derricks to safely hoist loads and discuss safe work practices that will protect you from injuries related to rigging. 1

2 So what do you need to know to be an effective and safe rigger? Riggers must know the basics of crane operations, including the limits of the equipment. Often, accidents involving cranes occur because the personnel involved pushed a crane beyond its capability. Experienced, reliable riggers know that they are part of a team that s performing a difficult job. Choosing the right sling and other hardware takes judgment born of experience. But you can learn the basics now, including learning to carefully check the load limits of any hardware you use. It s essential that you inspect your rigging equipment and hardware with care, using established criteria. Slings or other hardware can break, often at the worst time, when under the stress of a load being lifted. We ll discuss the basics of sling inspection today. You must be a trained and designated competent person before you can inspect rigging. Finally, you must know how to rig a load correctly. Again, there is plenty to learn, and your exact method of rigging will vary with the situation, equipment, and load, but this session will provide the basics. 2

3 Rigging the load is perhaps the single most important job of a crane operation. Poor rigging of a load can result in personal injury and property damage. Rigging refers to the hardware and equipment used to attach a load to a crane or derrick. Rigging also applies to crane assembly and disassembly operations. 3

4 A rigger is a person who rigs a load to a crane or derrick equipment, or assembles and disassembles a crane and derrick. He or she is required whenever workers rig, hook and unhook, or guide a load. A rigger may also be the crane or derrick operator if he or she is certified or licensed to operate the equipment. Anyone running a crane operation is required by law to use a qualified rigger during hoisting activities for crane assembly and disassembly work, and whenever workers are within the fall zone and hooking, unhooking, or guiding a load, or doing the initial connection of a load to a component or structure. A rigger must be qualified ; that is, he or she has to either: Have a recognized degree, certificate, or professional standing; or By extensive knowledge, training, and experience, successfully demonstrate the ability to solve problems related to rigging loads and properly rig the load for a particular job. It doesn t mean that a particular rigger has to be qualified to do every type of rigging job. For example, a rigger may be qualified to assemble or disassemble crane equipment, but the same rigger may not be qualified to rig unstable, unusually heavy, or eccentric loads that may require a tandem lift. In such a case, a second rigger qualified to rig a tandem lift will be needed. A good rigger carefully prepares a lift and should be able to anticipate and solve any problems related to rigging the load and handling emergencies. 4

5 Because crane operations can be hazardous and complicated, the federal Occupational Safety and Health Administration, or OSHA, has adopted regulations to ensure cranes and derricks are used safely in construction workplaces. The rules include requirements for properly rigging equipment for material handling. Copies of the regulations are available for you to review. Make sure you re familiar with the regulations and recommended practices for crane operations and rigging for your particular operations. 5

6 Several hazards are common to most cranes in construction work, including rigging operations: Being struck by a load caused by circumstances other than the failure of the boom or cable; Electrocution, especially where the crane or rigging components contact live overhead power lines; Being crushed during assembly or disassembly of the crane; Failure of the crane boom, cable, or the rigging hardware; Crane tip-over; Being struck by the crane cab or counterweight; A load becoming lodged or misaligned by an obstruction; Falls and a falling load. 6

7 There are several potentially unsafe conditions during hoisting and rigging operations that create hazards and dramatically increase the risk of injury to workers. Some common unsafe conditions to look out for are: Defective components like damaged, frayed, or broken cables, bent hooks, or excessively worn slings; Unsafe crane parts, such as an unsecured boom or damaged outrigger; Soft ground that will move under the weight of a crane; A load that s incompatible for the type of rigging used, or a load that exceeds the lifting capacity of equipment; High winds. 7

8 Bad weather; Excessive heat or cold Corrosion Work near or under a live power line; and Untrained or inexperienced workers, especially when they re not carefully supervised. 8

9 So let s begin by learning a little more about cranes and crane operations. Cranes used in construction work come in a variety of forms and sizes, designed for different situations or uses. The following list identifies some common types of cranes used in construction. The mobile crane has a truss or boom mounted on a mobile platform. The boom is hinged at the bottom and can be raised and lowered by cables or by hydraulic cylinders. For example: The crawler crane Truck-mounted cranes, which are mobile cranes mounted in the bed of a truck All-terrain cranes with a base or wheel bed much like that of an all-terrain vehicle Hydraulic cranes The tower crane, which is fixed to the ground or jacked up and supported by a structure, such as a building under construction. These cranes can be tall, with a high lifting capacity. A derrick, which is powered equipment with a mast or similar structure held at or near the end by guys or braces, with or without a boom, and its hoisting mechanism. Cranes used for construction are equipped with outriggers for stability. 9

10 Before you participate in any lift operations or assemble and disassemble equipment, thoroughly acquaint yourself with the rigging equipment and hardware. Make sure all the gear is in good working condition according to manufacturer specifications and crane regulations. Verify that you use the right equipment and hardware for the particular operation. Rigging equipment and hardware include: All fasteners and attachments, including hooks, shackles, links, wire rope clips, swivels, turnbuckles, eye bolts; Slings; and Any other accessories used for rigging operations, such as spreader beams and padding. We ll start our discussion of rigging equipment with slings. 10

11 Several materials are used to make slings, including alloy steel chain, wire rope, fiber rope, metal mesh, and synthetic web slings. Alloy steel chain slings are commonly used because of their strength. They can accommodate different shapes of the load. Alloy steel chain slings are often the best choice for lifting materials that are very hot, because these slings can be heated to temperatures up to 1,000 Fahrenheit; however, when they are consistently exposed to severe temperatures over 600 F, the working load limits must be lowered according to the sling manufacturer s recommendations. Special care should be taken when using alloy chain slings because they can be easily damaged by sudden shocks or jolts. Cracks, cracked hooks, and bent or elongated links are all indications that the sling is unsafe and should be rejected or discarded. We ll talk more about this in the discussion about inspections. 11

12 Another type of sling material is wire rope. Wire rope slings are composed of individual wires that have been twisted together to form strands. The strands are then wound around a core to form a wire rope. When wire rope has a fiber core, it is usually more flexible but is less resistant to environmental damage. A core that is made of a wire rope strand tends to have greater strength and is more resistant to heat damage. These types of slings can experience cracking of individual strands and kinking, which distorts their geometry. Use Tables H-3 to H-14 in the rigging equipment regulation to determine the safe working loads of various sizes and classifications of wire rope slings, or refer to the recommendations of the sling manufacturer for sizes and classifications not included in the tables. 12

13 Wire rope is often referred to as right lay or left lay, with regular or lang lay configurations of the strands in relation to the rope. Let s review these terms. The lay of a wire rope describes the direction the wires and strands are twisted in during the construction of the rope. Right lay means that the strands pass from left to right around the core, forming a right-hand helix. Right lay rope is the most common and is used for the widest range of applications. With left lay rope, the strands pass from right to left around the core, forming a left-hand helix. Left lay rope has its greatest usage in situations where the rotation of right lay would loosen couplings. The rotation of a left lay rope tightens a standard coupling. 13

14 Lay also refers to the direction the wires are wound in the strands in relation to the direction of the strands around the core. In regular lay rope, the individual wires in the strands are laid in one direction while the strands in the rope are laid in the opposite direction. Regular lay ropes have good resistance to kinking and twisting and are easy to handle. They are also able to withstand considerable crushing and distortion due to the short length of exposed wires. Regular lay combined with right lay rope has the widest range of applications. In lang lay rope, the wires are twisted in the same direction as the strands. Lang lay ropes are more flexible and have greater wearing surface per wire than regular lay ropes. In addition, since the outside wires in lang lay ropes lie at an angle to the rope axis, internal stress due to such uses as bending over sheaves and drums is reduced. This means lang lay ropes can be more resistant to bending fatigue. Lang lay rope is recommended for many excavating, construction, and mining applications, including draglines, hoist lines, and dredge lines. 14

15 Another type of sling is made of wire or metal mesh. These slings are much like chain mail in composition. They conform to the shape and contours of a load and are strong and durable. Wire or metal mesh slings are often used in basket or choker hitches, as well as vertical hitches. When inspecting these slings, be sure to look for any broken welds, cracking or broken brazed joints along the side of the sling, or distortion of the handles. These are signs of a weakened sling. 15

16 Natural and synthetic fiber rope slings are used primarily for temporary work. They are also the best choice for use on expensive loads, highly finished parts, fragile parts, and delicate equipment. Fiber rope slings are made with conventional three-strand construction and are flexible, pliant, grip the load well, and do not mar the surface of the load. They should be used only on lighter loads, however, and should not be used if there is a danger that they will cut on sharp edges or be damaged by abrasive material. They can also weaken in high temperatures and may be ruined by exposure to certain chemicals, such as strong acids. The choice of fiber rope type and size depends on the nature of the load, its weight, and the sling angle. Remember that these slings can stretch extensively when wet. Always inspect fiber rope slings thoroughly before each use. Keep in mind that they generally deteriorate more rapidly than chains or wire rope slings. 16

17 Synthetic web slings are used for many of the same applications as fiber rope slings and have similar qualities. For instance, both types of slings should not mar the surface of a load. However, they can be much stronger and capable of lifting heavy loads and are more resistant to abrasion and chemicals. Synthetic web slings are usually made of nylon, polypropylene, or polyester (such as Dacron ). Each material has slightly different properties. For instance, Dacron is resistant to acids, but can degrade if exposed to bases, and is resistant to stretching. Synthetic web slings flex to the contour of the load to keep it tightly gripped. Besides resisting abrasion and some chemicals, synthetic slings are generally unaffected by mildew and will not rot or biodegrade. They can be used at relatively high temperatures. 17

18 When using synthetic slings, always follow the sling manufacturer s instructions, limitations, specifications, and recommendations. Do this when using synthetic slings during assembly or disassembly rigging, even when your employer has its own assembly and disassembly procedure as an alternative to the manufacturer s other procedures. Protect them from abrasives and sharp or acute edges. Also protect them from configurations that might reduce the sling s rated capacity. Never use nylon web slings where any types of acids or phenolics are present. Never use polyester and polypropylene web slings or slings with aluminum fittings where any type of caustics are present. 18

19 Before we move on to the rest of this session, let s review this information on sling materials and types with a short exercise. Match the type of sling at left with the descriptor at right. A chain is for heavy or hot loads With wire rope, lay is important Metal mesh is similar to chain mail Fiber rope is for light loads only; and Synthetic web is unlikely to biodegrade 19

20 We ve covered a lot of ground already. Are there any questions about the: Definitions of rigging and rigger responsibilities? Rigging hazards and unsafe conditions? Rigging equipment and hardware? Types of slings? 20

21 Let s move on to sling inspection. Remember that you must be a designated competent person before you can inspect slings and other rigging equipment. Keep in mind that even if you select the right kind of sling, you may still be headed for trouble if the sling is not in good condition. Additional inspections must be performed while the sling is being used where service conditions warrant. So, even if you ve just used a sling, it s a good idea to inspect it before using it again because damage may have occurred during the last lift. Damaged or defective slings must be removed from service immediately. While exact criteria for inspection vary with the type of sling and what it s made of, general rules to follow when inspecting any sling include: Look for excessive wear, especially areas that are in regular contact with the load; unraveling of the fibers or wires that make up the sling; and places where abrasion has degraded or weakened the sling. Slings can also lose their shape and become distorted or stretched. This signals a weakened condition. Metal slings or components of slings can crack, become pitted, or corrode. While light rust may be acceptable, excessive pitting or corrosion can lead to a broken sling. Heat stress or scorching can weaken a sling, cause it to lose its form, or become brittle. Certain chemicals can eat away at slings or break down their fibers. 21

22 Now let s discuss some inspection criteria for some of the major types of slings. When inspecting an alloy steel chain sling, it is important to inspect the total length of the sling, as any place may be the proverbial weak link in the chain. Inspect the inside ends of each link because that s where the links bear the weight of the load. You can see this part of the chain by pushing links together so that the inside surface becomes clearly visible. Wear may also occur on the outside of links when the chain is dragged along abrasive surfaces or pulled out from under heavy loads. Check for excessive wear, nicks and gouges, and stretching. Links that are noticeably elongated or show cracking are always suspect. According to OSHA rules, a sling that has stretched to more than 3 percent longer than it was when new is unsafe and must be taken out of service immediately. Binding is another warning sign of a weakened sling. Binding occurs when a sling has become deformed to the extent that its individual links cannot move freely. Make sure there are no defects anywhere. Be sure sling labels and identifications are in place and readable. Look for illegal job or shop hooks and links or makeshift fasteners formed from bolts, rods, etc., or other such attachments that are not allowed to be used. 22

23 Many operating conditions affect wire rope life, including bending, stresses, loading conditions, jerking, abrasion, corrosion, sling design, materials handled, environmental conditions, and the history of previous usage. That s why it s essential to inspect wire rope slings before each use. Check for: Cracking and pitting; Excessive wear and kinking; Deformed wires or lay; Corrosion or rust; Heat stress, which may result in a discoloration of the metal or a drying of internal lubrication; Broken wires. If, in any length of 8 rope diameters, the total number of visible broken wires exceeds 10 percent of the total number of wires, remove it from service; and End fittings and other components, which should also be inspected for any damage that could make the sling unsafe. 23

24 When inspecting a fiber rope sling before use, start by examining its surface. Look for dry, brittle, scorched, or discolored fibers. If any of these conditions are found, the sling should not be used. Next, check the interior of the sling. It should be fairly clean. The presence of powder or dust on the inside of the fiber rope may demonstrate excessive internal wear; the sling may be unsafe. Finally, scratch the fibers with a fingernail. If the fibers come apart easily, the fiber sling has probably suffered chemical damage and must be discarded. 24

25 Inspecting web slings is an important step in making sure they operate safely. Check synthetic slings and round slings for acid or caustic burns, punctures, holes, wear, cuts, tears, snags, broken stitches, worn stitches, excessive abrasion, embedded particles, and knots. These problem signs are cause for the slings to be removed from service. Also, check for broken or worn stitching in the cover that exposes the core fibers and web slings that have visible signs of protruding red threads. Check for melting or charring of the sling surface heat damage causes the webbing to harden and stiffen. Look for distorted fittings. Check shackles and hooks to ensure they are the right sizes to handle the load. 25

26 You can extend the life of a sling considerably with proper maintenance. One relatively simple step is to clean the sling. This will remove material that may be abrasive or produce snags, or that could degrade the sling through a chemical reaction. Some damaged slings may be repaired. For instance, nicks or gouges in a chain sling can be filed smooth, but it is essential not to reduce the diameter of a link below the manufacturer s recommendations. If repairing a sling may render it unsafe, the sling should be discarded. Wire rope slings need occasional lubrication. The heavier the loads, the greater the number of bends, or the more adverse the conditions under which the sling operates, the more frequently lubrication will be required. Finally, slings should be stored in a well-ventilated, dry storage area. Don t store slings on the ground or allow them to be exposed to the elements when not in use. A storage rack is generally used. Once you are done using a sling, check it for damage, and if none is found, return it to storage. 26

27 Rigging hardware, such as fasteners and attachments, requires the same level of care and attention to safety as slings and crane equipment. There are some general rules to follow when choosing and using hardware. For example: Never put loads on hardware that exceed their recommended safe working load. Remove any rigging gear that s not being used from the immediate work area in order to eliminate hazards to employees. Mark or label special custom hardware with its safe working loads. Keep in mind that custom hardware and accessories must be proof-tested to 125 percent of their rated load. Such hardware includes design grabs, hooks, clamps, or other lifting accessories used to lift items such as modular panels, prefabricated structures, and similar materials. 27

28 Each day before being used, all fastenings and attachments have to be inspected for damage or defects by a designated competent person. Rigging hardware, such as shackles, links, wire rope clips, and end fittings, must also be inspected thoroughly and treated with care. Retire hardware if signs of wear or deformation, such as cracks, nicks, or gouges, are found. Remove the equipment from service if excessive wear of more than 5 percent is detected in the throat or eye of a shackle or more than 10 percent wear is found in other areas. Malfunctioning, missing, or improperly installed hardware must be removed from service. Check latches, swivels, bearings, locking devices, and the installation of wire rope clips and wedge sockets. It s also essential to retire hardware that has been altered on the job, such as by cutting or welding. 28

29 The crane hook is a sturdy device capable of enduring great stress, but it must be inspected daily before use. All hooks must have a safety latch or clip. This prevents the hook from twisting out of the ring or another device to which they are attached. If a hook does not have a safety clip or latch, or if the clip is broken, replace the hook or have the safety clip repaired. Hooks can crack, bend, or distort, and must be discarded when this happens. A hook opened more than 15 percent of the normal throat opening measured at the narrowest point must be discarded. A hook twisted more than 10 degrees from the plane of the unbent hook must be removed from service. Many times, the hook requires nondestructive testing to ensure there are no stress cracks. 29

30 Part of the art of the rigger s work is to employ the proper hitch for a lift. Many types of hitches may be used, depending on factors such as the weight and shape of the load and the sling or slings being used. A few commonly used hitches are: The single vertical hitch, where a single sling is used for a vertical lift; The bridal hitch, in which two or more slings meet at the crane hook; The basket hitch, in which a sling wraps around the load or a part of the load to support it; and The choker hitch, where the hitch tightens around the load as it is lifted. If you are unsure about which type of hitch is best for a particular lift, talk to the people who know, such as your supervisor, the crane operator, or a more experienced rigger. Never twist a chain or sling to adjust its length this will compromise its load-bearing capacity. You ll learn much more about how to hitch particular loads and when to use certain hitches as you gain experience. 30

31 Now that you have information about the rigging equipment, you can plan the lift. No matter what type of crane is being used, you must collect certain information before you can make a safe lift. First, you must know the weight of the load. The weight may be found on the container, or in shipping papers or other document. In determining the load, include the weight of the sling and rigging hardware. If the load weight can t be determined using documentation, you must calculate the load yourself. Second, determine the rated capacity of the crane or derrick and the rigging equipment, including slings and hardware; the rated capacity is the maximum amount of weight a crane and rigging can safely lift. The rated capacity is marked directly on the crane and on the rigging equipment and hardware. Depending on the type of equipment and the nature of the lift, other factors that can change even during the lift must be considered. For instance, a boom extended too far or a lift performed at the wrong angle may result in a crane becoming unbalanced or tipping over. We ll touch on these other factors in a minute. Finally, the crane s load chart is used to determine if a lift can be done safely, in consideration of factors such as load weight, boom length and angle, and lift radius. A lift should never be attempted if it is not within the capabilities of the equipment or if safety cannot be ensured. 31

32 Even when you know that your equipment is suitable for the weight of the load, there are still some serious questions you must answer before you conduct the lift: Will the angle of the sling take away any of its capacity? Have you rigged the load to the center of gravity of the crane and lift line? Are there any sharp surfaces or corners in the rigging that could cause a sling to tear? Should padding be used to protect the sling? Will the load be under control along the entire path of the lift? Should a tag line be used to guide the load? Are there any obstructions along the lift path that must be cleared? Can they be moved out of the way? Will the suspended load be clear of all personnel? Do unusual environmental conditions, such as high winds, rain, or heat, need to be considered? As you can see, there are many factors to keep in mind. That s why it is smart to discuss each job with everyone involved and make doubly sure you are making the right decisions. 32

33 That seems like a long list of questions that need to be answered. Why can t you just size up the load, slap on some rigging, and hoist away? Maybe nothing will go wrong. The problem is, crane operations are simply too hazardous to leave to chance. So, the more factors that need to be considered, the more important it is to slow down and make the right decisions. 33

34 Part of your lifting plan includes choosing the right sling for the lift. A sling that has been well selected and is properly functioning will keep the load stable and secure during the course of the lift. However, using the wrong sling may lead to a load that sways, slips out of the sling, or causes the sling to snap or otherwise fail under stress. Ensure that the rated capacity of the sling is sufficient to lift and carry the load. Ensure that the manner of rigging does not compromise its strength. The material composition of the sling is very important for reasons stated in previous slides; for example, a fiber rope sling may be best for light loads and where the surface of the load must be protected, and a chain sling may be best when lifting high-temperature loads. Consider the sling size, design, and configuration for the type of load being lifted; for example, larger and heavier loads may be safely moved if the weight of the load is distributed among more sling legs. Make sure the sling is in good condition according to manufacturer specifications. Each sling should have a tag or stamp that states the rated capacity, the date it was put into service, and its length. 34

35 We ll consider how to select a wire rope sling as an example. When selecting the sling to give the best service, there are several characteristics to consider, such as strength, flexibility, or the ability to bend without distortion, and durability, or the ability to withstand wear and abuse. The strength of a wire rope is a function of its size, grade, and construction. As a sling deteriorates from use, its strength and lifting capacity are reduced. A sling loaded beyond its strength will fail. For this reason, slings and all fastenings must be inspected thoroughly each day before use. Generally, more flexible ropes are selected when smaller radius bending is required. Smaller wires bend more readily and therefore offer greater flexibility. However, less flexible ropes should be used when the rope must move through or over abrasive materials, as they are less likely to be damaged. Durability should also be considered when selecting a wire rope sling. Padding is often applied to edges of a load to increase the radius of the bend, and to reduce fatigue and damage to the sling. It s important to take good care of your slings and make sure that how you use, inspect, and store them always follow the manufacturer s recommendations. In addition, standard practice is to hang the slings when not in use, not lay them down. 35

36 A crane operator uses data such as rated capacity and the load chart to decide if a lift can be made safely with a particular crane. For the same reason, you as the rigger must check safety data when choosing rigging hardware. Always carefully check the rated capacities or working load limits of all slings and the rigging hardware, including hooks, shackles, turnbuckles, swivels, eyebolts, and other components. The load limits should be stamped on the slings and hardware. The rigging equipment capacities are just as important as the rated capacity of the crane. Never use any part of rigging gear if you can t verify its rated capacity or load limit. Consider the load bearing effect of the sling angle when choosing your rigging gear. The sling angle will affect the capacity, with capacity lowered as the angle is reduced. A sling that bears a load at a 30 degree angle may have only a fraction of the lifting capacity of a sling that is at 60 degrees, vertical to the lift line. As stated earlier, the sling angle can be increased with additional sling legs to distribute the load better. 36

37 Make sure all parts of each piece of rigging hardware are in good working order. For example, check to be sure that the positive latching mechanism on the hook is working properly. Match the type of hardware you use to the lifting conditions. For example, you may want to use an accessory like a spreader beam to support long loads during lifts. The beam eliminates the hazard of the load tipping, sliding, or bending as well as any tendency of the sling to crush a load. As you can see, it is essential that the crane, load line, hook, and all components of the rigging be designed for the load you plan to lift. 37

38 As you get ready to prepare a load for a lift, protect yourself by donning all required personal protective equipment, or PPE. This may include a hard hat, safety shoes, safety glasses or goggles, and work gloves. Before lifting the load, ensure that the hook and hoist line are directly over the load. If they are not, the load will move or swing, potentially causing an injury to someone or damaging facilities or equipment. Ensure that the load is not lagged, clamped, or bolted to the floor. Also, check that the hoist chain or line and the slings are not kinked or twisted around each other. This could cause the load to twist, rotate, or flip once it is lifted. 38

39 Always attach the sling to the load first, then attach the sling to the hook. This is called rigging up the load. Hooks are designed to carry the load in the center of the hook, which is the thickest part. Never pick up a load with the hook s tip; a load attached this way can easily slip and the safety clip won t function as expected. Also, the hook tip itself will also open and weaken. The hook latch or clip must be closed to secure loose slings. Check once more to make doubly sure that all rigging components and any safety devices are in place and that the load is free of any restraint. Also, check again to be sure that the path of the lift is clear and that all personnel are away from the area while the load is being raised, moved, or lowered. Ensure the load will not get hung up on its path of travel. Test the lift and hitch by lifting the load a few inches, at first, to make sure it is well secured and balanced. Guard against shock loading by slowly taking up the slack in the sling. Use a tag line to keep the load from turning or swinging during the lift; use extreme caution and stay out from under the load. The load should be lifted as close to the floor or ground as possible when traveling. 39

40 Throughout lifting operations, the crane operator must be in contact with someone on the ground through signals. The rigger is often the person appointed to give signals. If that person is you, make sure you follow these signaling rules and guidelines: It is essential that the crane operator remain in view of the rigger and other crew on the ground near the load. Signals to operators must either be transmitted by hand, voice, other audible signal, or new signals at least as effective as hand, voice, or audible. When using hand signals, the Standard Method must be used. The method of signaling has to be appropriate to site conditions. Also ensure that the signaler has a clear view of the load, the crane operator, and the travel pathway. Only one member of the crew will give signals to the operator, unless someone else sees an unsafe condition. Then, anyone can give the emergency stop signal. However, it is essential that everyone on the ground recognize the signals and understand where the load is headed. Getting in the way of a load, or standing under it, have gotten many people killed over the years. After checking to make sure everyone is clear of the area, the signaler signals the crane operator to hoist the load. 40

41 Now that the load is safely under way, let s review a list of nevers involving crane operations. Accidents and injuries occur when people do something they never should have done! Never use a hoist chain or load line that is twisted or kinked. Never use the hoist chain or line as a sling by wrapping it around the load. This can damage, cut, or kink the chain or line. Do not attempt to lift the load by the block hook. Attach the load to the block hook with appropriate slings or other approved devices. Never stand on a load as it is being lifted. Never use a sling or piece of rigging hardware that is not in good condition. Never allow a load to be lifted if you are unsure about safety. 41

42 And that s not all. Here are a few more nevers. Never allow more than one person to control a lift or give signals to a crane or hoist operator except to warn of a hazardous situation. Never work or stand under a suspended load or allow anyone else to. Never turn your back or walk away until a load is completed. Watch the load and rigging with care and be prepared to stop the job if you see an unsafe condition. 42

43 We ve discussed quite a few new terms today. Let s see if you remember some of them. Provide the term described in each of the sentences above. 1. A type of hitch in which two slings meet at the crane hook is a bridle hitch. 2. An essential part of the crane hook that keeps the sling from sliding off is a latch or clip. 3. A term for describing the pattern of wires in a wire rope is lay. 4. The maximum weight a crane or sling will support is rated capacity. How did you do? Did you get them all correct or do you need to go back and review? 43

44 Now it s time to ask yourself if you understand the information presented so far. Do you understand about: Inspecting equipment before use? Maintenance of slings, equipment, and hardware? Hardware selection? Preparing for and conducting a lift? 44

45 There is certainly a lot to learn about rigging a crane; that s why crane rigging is often referred to as an art, and it takes years of practice to be a true expert. It is important that you continue to learn and find out all you can about the practice of rigging cranes. As you learn, keep in mind that you must be cautious at all times, and think safety. It is up to you to never allow a lift that you even suspect could be unsafe. Finally, while unusual lifts may require special thought, even routine lifts can be deadly if a sling fails or if the rigger forgets to fasten the crane hook. That s why it is essential that you follow all procedures every time, and think safety. 45