Workplace Hazards and Risk Control
Excavation – Hazards and Control Measures:
Hazards associated with work may include:
· Unexpected collapse of the trench wall /cave in: Sudden collapse of the excavation walls normally happens due to the condition of soil, presence of water, vibrations due to activities in the vicinity, lack of support etc. Severe crush injuries can result from even relatively small collapse as soil is very heavy
· Falling of persons / workers into the trench: Falling of persons normally happens as a result of unfenced edges or while climbing in to or out of the excavation from ladders
· Presence of toxic gases during the trenching: Excavations can get filled with any gas that is heavier than air or other gases in the surroundings can get leach out of the soil and into excavation · Accumulation of water: Flooding usually happens from surface water due to heavy rain, ground water or due to the rupture of water pipelines.
· Oxygen Deficiency: Deficiency of oxygen may happen due to the depth of excavation / Trench
· Fire due to the presence of underground utilities carrying flammable materials
· Collapse of the adjacent structure: Excavation works can affect the foundations of nearby buildings causing destabilizing or collapse of the structure
· Biological Hazards
· No proper access/ egress
· Mobile equipments falling into the pit
· Inadequate illumination
To avoid the unexpected collapse of the trench / excavation wall, the wall should be protected by means of sloping, shoring, benching or shielding. Check for the presence of underground utilities before the start of the work. The plans of the area of the excavation should be obtained. The buried services should be located using surface clues and detection equipment. The buried services should be discovered by careful digging with hand. Before performing the mechanical excavation, underground utilities should be isolated if possible.