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Guideline No. 23: Scaffolding

The erection and dismantling procedures are to be conducted by qualified technicians. This includes inspecting equipment before assembly. Scaffolds shall be inspected before use and after any modifications (as per section 130(3) of O. Reg. 213/91).

Follow the manufacturer’s instructions and replace any damaged components. Safety takes precedence and includes the following:

  1. The 3 to 1 rule. The total working height of a freestanding scaffolding tower should be three (3) times the distance of the narrowest side of the base (if this is a measurement of outriggers, they must be set symmetrically about the tower). If the height exceeds three (3) times the least lateral width, the scaffold tower must be secured to a suitable structure or the tower should be braced using guy wires or other suitable support.
  2. If the height of the scaffolds exceed 15 metres for frame scaffold or 10 metres for tube and clamp scaffold, the scaffold shall be designed by an engineer and erected according to the design (as per section 130(1) of O. Reg. 213/91).
  3. All towers should be plumbed and levelled.
  4. Overhead dangers should be identified and controlled.
  5. When erecting scaffolding near power lines stay outside the limits of approach as required by section 188 of O. Reg. 213/91 and specified below:
Minimum distance from live power lines for electricity
Voltage of live power lineMinimum Distance
750 to 150,000 volts3 metres (10 feet)
150,001 to 250,000 volts4.5 metres (15 feet)
250,001 volts and over6 metres (20 feet)
  1. Always check for overhead power lines before moving any scaffolds.
  2. Observe regulated limits of approach around live electrical wires and equipment.
  3. Overhead power lines should be de-energized or insulated by the local utility company.
  4. Use appropriate fall protection during the erection and dismantling of the scaffold (as required by section 125(2) of O. Reg. 213/91)
  5. When guardrails cannot be installed on the scaffold, use appropriate fall protection equipment when working off scaffold (as required by section 26(3) of O. Reg. 213/91).
  6. Use a ladder to access the work areas of the scaffold tower.
  7. Never overload a scaffold with materials or people as per section 126(3) of O. Reg. 213/91. Do not exceed the manufacturer’s load specifications.
  8. People shall not remain on a rolling scaffold when it is being moved unless they are wearing adequate fall protection and the scaffold is being moved on a firm level surface (as per section 129(3) of O. Reg. 213/91.

This guideline should be read in conjunction with Guideline #21 Working at Heights.

Updated: April 27, 2022
Published: April 27, 2022