Preventing Engulfment in Trenches & Pits

Talking Points

1. 1 Any trench deeper than 1.5m requires shoring or benching — no exceptions under WHS Regulation 2011
2. 2 Type of soil determines shoring requirements — get a geotechnical assessment if soil is unknown
3. 3 Spoil must be kept at least 1.5m back from the edge of any excavation
4. 4 Do not work under services (pipes, cables) that could move — consult plans and support structures
5. 5 Workers must not enter any excavation where water has accumulated until water has been removed and soil integrity confirmed
6. 6 If you see tension cracks, bulging walls, or water seepage — stop work, evacuate, inform supervisor
7. 7 Access ladder or step must reach to within 1.5m of the trench floor — and ladder must extend 900mm above ground level
8. 8 Keep vehicles and plant away from trench edges — vibration and load can trigger collapse

Control Measures

• Excavation permit system including soil assessment and shoring method
• Shoring equipment on site before excavation begins — type must match soil class
• Spoil management plan: spoil pile location specified in permit
• Daily inspection of excavation edges and shoring before each shift
• Trench access ladder positioned before any worker enters