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Load Rating Chart

 
  
 
6. Gantry and/or live mast in the highest position. 7. Quadrant of operation (that is, over the side, over the rear capacities). Load Rating Chart Atypical load rating chart is shown in figure 12-47. To determine the capacity of the crane by using the load chart, the operator must know the length of boom, the load radius, the boom angle, and if the lift is to be performed over the side or over the rear. When  performing  lifts  using  the  boom  angle indicator that indicates an angle not noted on the load chart, use the next lower boom angle noted on the load chart for determining the capacity of the crane. For example, using the load charts in figure 12-47, the crane is rigged with 60 feet of boom, and the boom angle indicator  indicates  a  boom  angle  of  57  degrees.  A 57-degree boom angle load capacity is not noted on the load chart, so you must use the next lower noted boom angle of 53 degrees for determining the capacity of the crane. NOTE: Do not rely on the boom angle indicator for radius accuracy when lifts exceed 75 percent of the rated capacity. Measure the radius to avoid the possibility of error. When using a radius measurement not noted on the load charts, use the next longer radius measurement noted on the load chart for determining the capacity of the crane. For example, using the load charts in figure 12-47, the crane is rigged with 50 feet of boom, and the radius  measurement  is  32  feet.  A  32-foot  radius measurement is not noted on the load charts, so you must use the next longer radius measurement of 35 feet noted on the load chart for determining the capacity of the crane. The number of part lines reeved on the main hoist block can affect the capacity of the crane. If the crane is capable of being reeved with an eight-part line and the reeving is changed to a six-part line, the capacity of the crane changes. On newer models of cranes, the capacity for  different  parts  of  line  configurations  is  noted  on  the load charts. On older models, you must refer to the manufacturer’s  manual. The  load  chart  provides  the  capacity  of  the  crane with  outriggers  set  and  without  outriggers.  “Outriggers set” means the outriggers are fully extended and the weight of the crane is off of the suspension system or the tires are off the ground. If a situation arises where the outriggers cannot be fully extended, you must use the without outriggers load capacity ratings. NOTE:  Load  capacities  change  when  swinging from each quadrant of operation, such as from over the rear to over the side. SAFE LIFTING The  following  factors  are  basic  guidelines  to perform  safe  daily  crane  operations: 1. Determine the weight to be lifted and the crane required to make the lift safely. 2.  Travel  the  proposed  route  the  crane  will  follow to and from the project site, and complete the Crane Lift Checklist. 3. Obtain the travel permits if required. 4. Brief operators and riggers on the specifics of the lift and travel conditions. 5. Inspect the crane area setup for stability and safe operating  area 6.  Fully  extend  the  outriggers  and  use  them according  to  the  manufacturer’s  instruction. 7. Check the crane for levelness. 8. Inspect all rigging hardware. 9.  Select  the  proper  sling  with  sufficient  capacity rating. 10. Center the sling in the base (bowl) of the hook to avoid hook point loading, and ensure the hook block is always placed over the center of the load to eliminate shock loading of the slings or cranes, resulting from load shifts when a lift is made. 11. Make ample safety allowances for unknown factors. 12. Stand clear of and do not walk under suspended loads. 13.  Boom  deflection. All   crane   booms   have deflection.  When  the  load  is  lifted  off  the  ground,  the boom  will  deflect,  causing  the  radius  to  increase. Increased radius may cause overloading of the crane. 14. An uncontrolled swinging load can cause the radius to increase. 15.  Clean  operating  area.  Water  coolers,  excess tools,  grease,  soda  cans,  and  other  unnecessary  items should be kept outside of the operating area of the crane. Water coolers must be kept off the crane to prevent 12-32


   


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