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804 Safe Scaffold Erection and Inspection
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Outrigger Scaffolds

An outrigger scaffold is a supported scaffold consisting of a platform supported by outrigger beams (thrustouts) projecting beyond the wall or face of a building or structure with the inboard ends secured inside the building or structure.

When inspecting outrigger scaffolds, check the following:

  • Make sure outrigger beams are:
    • secured in place to prevent movement
    • securely braced at the fulcrum point to prevent tipping
  • Make sure the inboard end of outrigger beams are:
    • not less than 1½ times the length of the outboard end, measured from the fulcrum point to the extreme anchorage point
    • securely anchored either by:
      • braced struts bearing against sills in contact with the overhead beams or ceiling
      • tension members secured to the floor joists underfoot
      • both braced struts or tension members
  • Check that the fulcrum point of outrigger beams rest on secure bearings at least 6 inches in each horizontal dimension.
  • If outrigger beams are fabricated in the shape of an I-beam or channel beam, make sure they are placed so that the web section is vertical.
  • Make sure the entire supporting structure is securely braced to prevent any horizontal movement.
  • To prevent their displacement, make sure platform units are:
    • nailed
    • bolted
    • otherwise secured to outriggers
  • Verify scaffolds and scaffold components are:
    • designed by a registered professional engineer
    • constructed and loaded in accordance with that design

Knowledge Check Choose the best answer for the question.

4-3. When inspecting outrigger scaffolds, the outrigger beams should be _____.