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Cranes and Slings

Cranes and Slings. Major Causes of Crane Accidents Contact with power lines Overturns Falls Mechanical failures. Crane Hazards. An unstable load, lack of communication, lack of training, and inadequate maintenance or inspection are major contributors to crane accidents.

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Cranes and Slings

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  1. Cranes and Slings • Major Causes of Crane Accidents • Contact with power lines • Overturns • Falls • Mechanical failures

  2. Crane Hazards • An unstable load, lack of communication, lack of training, and inadequate maintenance or inspection are major contributors to crane accidents. • Operators or others working in the area can be victims to “struck by" and "caught in" injuries. • Contact with power lines causes many accidents.

  3. Improper loading Excessive speeds No hand signals Inadequate inspection and maintenance Unguarded parts Unguarded swing radius Working too close to power lines Improper exhaust system Shattered windows No steps/guardrails walkways No boom angle indicator Not using outriggers Crane Hazards

  4. Crane Parts

  5. Rated Capacities • Make sure the crane operator can see the: • Rated Load Capacities • Operating Speeds • Special Hazard Warning or Instruction • APPLICABLE OSHA STANDARD • 1926.1501 (a)(2) Rated load capacities, and recommended operating speeds, special hazard warnings, or instruction, shall be conspicuously posted on all equipment. Instructions or warnings shall be visible to the operator while he is at his control station.

  6. Competent Person • The competent person must inspect all machinery and equipment prior to each use, and during use, to make sure it is in safe operating condition. • If it needs fixing, take it out of service and don’t use it until it is fixed

  7. Know the Weight of the Load • Refer to shipping ticket or other documentation • Ensure lift calculations are correct • Ensure load is within load chart rating for boom length and load radius of crane • Crane is rated by the maximum weight it will lift at a minimum radius and minimum boom length – the further from its centerpoint, the less it will lift

  8. Load Limiting Factors • Not level • Wind • Side loads • On its wheels • Lifting over the side • Use of extensions, jibs and other attachments • Limits of wire rope, slings and lifting devices

  9. Load Example – 30 ton crane • Will lift 60,000 pounds at 10 feet from the center pin of the crane • Based on level surface, no wind, and outriggers fully extended • At 25 feet from the center pin with an 80 foot boom, the capacity is only 14,950 pounds • At 74 feet from the center pin, the capacity is only 4,800 pounds

  10. Wire Rope Slings

  11. Alloy Steel Chains Adapts to shape of the load Can damage by sudden shocks Best choice for hoisting very hot materials Must have an affixed tag stating size, grade, rated capacity, and sling manufacturer

  12. Chain Wear When a chain shows excessive wear, or is cracked or pitted, remove it from service Non-alloy repair links can not be used

  13. Wire Rope Slings • Used to hoist materials • Selection considerations: • strength • ability to bend without cracking • ability to withstand abrasive wear • ability to withstand abuse Wire Core Center Strand Wire rope

  14. Damaged wire rope Crushed Rope Broken Strands Damaged wire rope must be taken out of service

  15. Protruding Ends Cover or blunt protruding ends of strands

  16. Wire Rope Clips When using U-bolt wire rope clips to form eyes, ensure the "U" section is in contact with the dead end of the rope Dead End This is the correct method

  17. Wire Rope Slings Remove From Service If these happen, remove the wire rope sling from service Kinking Bird Caging Crushing

  18. Synthetic Web SlingMarkings • Mark or code to show: • Name or trademark of manufacturer • Rated capacities for the type of hitch • Type of material

  19. Synthetic Web SlingStitching • Stitching is the only method allowed to attach end fittings to webbing, or to form eyes Stitching

  20. Synthetic Web Slings -Remove from Service • Remove from service if any of these are present: • Acid or caustic burns • Melting or charring of any part • Snags, punctures, tears or cuts • Broken or worn stitches • Distortion of fittings Heat Damage

  21. Sling Tables

  22. Sling Stress Example • From the table, a single branch with a 90 degree loading is rated at 3,250 lbs. • If there is a safety factor of 4, the chain could lift

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