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821 Cranes and Derricks Safety II
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Derricks

Construction

Derricks must be constructed to meet all stresses imposed on members and components when installed and operated in accord with the manufacturer's/builder's procedures and within its rated capacity. Load anchoring data developed by the manufacturer or a qualified person must be used.

Specific additional construction requirements are specified for:

  • guy derricks
  • stiffleg derricks
  • gin pole derricks
  • chicago boom derricks

Swingers and Hoists

The boom, swinger mechanisms, and hoists must be suitable for the derrick work intended and must be anchored to prevent displacement from the imposed loads.

Hoists must meet the following requirements:

  • Base mounted drum hoists must meet certain specified requirements of ASME B30.7-2001, Base-Mounted Drum Hoists.
  • New hoists must be load tested to a minimum of 110% of rated capacity, but not more than 125% of rated capacity, unless otherwise recommended by the manufacturer. This requirement is met where the manufacturer has conducted the testing.
  • Hoists that have had repairs, modifications, or additions affecting their capacity or safe operation must be evaluated by a qualified person to determine if a load test is necessary. If a load test is necessary, it must be conducted in the manner specified in the standard.

Knowledge Check Choose the best answer for the question.

7-5. New hoists must be load tested to _____ .