OHS Code Explanation Guide

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

Section 458 Installation of shoring, stringers or bracing

Subsection 458(1)

The greatest potential for worker injury exists at the bottom of a trench having unsupported walls. To reduce the likelihood of being injured by a trench wall collapse, workers must use a ladder and install shoring, stringers or bracing downward from the top of the trench, installing each brace in descending order.

Following this sequence, workers are always working in the protected zone. As the protection is installed, workers progress downward until the bottom of the trench is reached.

Subsection 458(2)

When removing shoring, stringers or bracing, workers must work in a sequence that is the reverse of the installation sequence. Specifically, the removal sequence must proceed upwards from the bottom of the trench so that workers are located above the zone of greatest potential for injury. Again, a ladder must be used to keep workers above any possible trench wall collapse.

Subsection 458(3)

Workers must install and remove shoring, stringers or braces as required by subsections (1) and (2). This means that workers must receive training in the employer’s safe work procedures for performing the work, be made aware of the requirements of subsections (1) and (2), and may require supervision by the employer.

Subsection 458(4)

If ground conditions deteriorate to the point that it is unsafe to remove shoring, stringers or bracing using the method described in subsection (2), the employer must develop a removal method that does not require a worker to be in the trench. Removal methods could involve use of equipment such as a crane, backhoe or other lifting/excavating equipment rigged or equipped, as necessary, to complete the job safely.