OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 32 Excavating and Tunnelling


  • Section 441 defines the terms “buried facility” and “hand expose zone” which reflect current industry practices in Alberta and requirements under the Pipeline Act. Section 441 also describes what is meant when the “ground is disturbed”.
  • Section 442 classifies soils into three categories: hard and compact; likely to crack or crumble; sandy or loose. The categories dictate how the walls of excavations and trenches are cut back or sloped.
  • Section 447 requires that ground not be disturbed until buried facilities have been identified and their locations marked.
  • Sections 447 and 448 clarify requirements that affect work involving buried facilities.
  • Section 451 requires that if walls of an excavation in soft, sandy or loose soil are cut back, they must be sloped from the bottom of the excavation and the walls must be at an angle of not less than 45 degrees (measured from the vertical).
  • Section 453 requires that loose materials be scaled and trimmed from spoil piles.
  • Section 455 requires that a safe point of entry and exit be located within 8 metres of any worker in a trench that is more than 1.5 metres deep.