Excavation and trenching
CHST written lesson, 11 min read. CHST Domain 1: Hazard and Risk Identification and Control
AI-drafted from the cited rules and fact-checked against them. Study aid, not site-specific safety advice. The official rule controls.
What you'll learn
- State the depth thresholds that trigger protective systems, egress and atmospheric testing
- Explain the competent person's inspection and monitoring duties
- Classify soil as stable rock, Type A, B or C and match it to a maximum slope
- Calculate the horizontal run of a sloped cut from depth and slope
- Apply distance, water, walkway and utility rules to a realistic trench
What this lesson covers
This lesson covers how trench and excavation rules are triggered by depth, who decides what on site, and how soil type sets the slope of a cut. It matters because depth thresholds, distances and soil classes are tested constantly, and getting them wrong on the job costs lives.
This lesson is included with a pass
Written lessons come with every CHST pass, along with the video lessons, the question bank, mocks and the tutor. $80 per exam or $143 for all three, for 180 days.
Try the free excavations and trenching practice questions
Visualize this
- Pick the soil and the depth and watch the maximum allowable slope redraw.
An interactive diagram, included with every CHST pass.