Excavation and Trenching

Overview

Excavation and trenching work can expose workers to sudden ground collapse, falling materials, hazardous atmospheres, underground utilities and moving equipment. Work should begin only after the excavation has been assessed by a competent person, underground services have been identified and suitable protective, access and inspection arrangements have been established.

Main Hazards

• • Cave-in or sudden ground collapse
• • Workers or equipment falling into the excavation
• • Falling spoil, tools or materials
• • Contact with underground electrical, gas or process lines
• • Unsafe entry and exit
• • Water accumulation or flooding
• • Hazardous or oxygen-deficient atmosphere
• • Mobile equipment operating near the edge

Essential Controls

1. 1Identify and mark underground utilities before excavation begins.
2. 2Have a competent person assess soil conditions, excavation depth and protective-system requirements.
3. 3Use suitable sloping, benching, shoring or shielding where required.
4. 4Provide safe access and egress, such as ladders, stairs or ramps.
5. 5Keep spoil piles, materials and equipment at least 0.6 metres from the excavation edge.
6. 6Use barriers, guardrails or warning systems around exposed edges.
7. 7Inspect the excavation daily and after rain, vibration, nearby loading or any condition change.
8. 8Control water accumulation with drainage, pumps or other suitable measures.
9. 9Keep mobile equipment away from unsupported edges and use a spotter where visibility is restricted.
10. 10Test the atmosphere where hazardous gases, vapours or oxygen deficiency may be present.

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