A 3D rendering of davit arms hoisting a powered platform

Roof Rigging – Launching a Platform Explained

Roof Rigged Davit Systems are designed for buildings where ground rigging is not ideal. Sometimes, site conditions, particularly at lower levels, do not allow for a platform to be picked up from the ground. Roof conditions such as permanent equipment, parapet/screen wall height, building shape, and especially suspension height must all be taken into consideration when deciding between designing for roof rigging vs. ground rigging.

In cases where roof rigging is required, there is a very specific set of directions that need to be followed in order to ensure safety and compliance with CSA Z91 (Health and Safety Code for Suspended Equipment Operation).

Requirements for Roof Rigging:

Access to and egress from the working platform must be from a safe surface that does not require workers to climb a parapet or guardrail. The platform must also be provided with wheels, casters, or a carriage for horizontal movement.

See the steps to launching a roof rigged platform below:

  1. Roll the platform into pick up position on the main roof travel path. Ensure the platform suspension points are positioned within the trolley suspension range of the davit arm.
  2. Then, workers on the platform operate the hoists to the platform so the underside of the casters will clear the height of the parapet. Once this is done, workers on the roof push one side of the platform toward the parapet until the davit boom of Davit Arm 1 is roughly parallel to the parapet wall. The boom of the davit arm 2 stays in roughly the same position.
  3. The workers of the roof continue to push the platform outboard and the boom of the second davit arm starts to rotate towards the parapet wall.
  4. As the workers on the roof continue to push the platform outwards, the davit booms should eventually become roughly perpendicular to the parapet and the platform at this point will be fully outboard and ready to descend to access the building façade. Note: once the platform is outboard, the davit booms may be rotated to adjust the drop position of the platform as required.

Pro-Bel Davit Systems

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