Excavation Hazards

 

Excavation work generally means work involving the removal of soil or rock from a site to form

an open face, hole, or cavity using tools, machinery, or explosives.

 

Identifying the hazards

Examples of excavation specific hazards include:

Underground essential services like gas, water, sewerage, telecommunications, electricity, chemicals, and fuel or the refrigerant in pipes or lines. Information about the location of these and other underground services, such as drainage pipes, soak wells, and storage tanks, in and adjacent to the workplace, must be established before directing or allowing excavation work.

 ·         The fall or dislodgement of earth or rock

·         Falls from one level to another

·         Falling objects

·         Inappropriate placement of excavated materials, plant, or other loads

·         The instability of any adjoining structure caused by the excavation

·         Any previous disturbance of the ground including previous excavation

·         The instability of the excavation due to persons or plant working adjacent to the excavation

·         The presence of or possible inrush of water or other liquid

·         Hazardous manual tasks

·         Hazardous gases

·         Hazardous chemicals (e.g. These may be present in the soil where excavation work is to be carried out)

·         The hazardous atmosphere in an excavation (e.g. Using methyl ethyl ketone (MEK) solvent for PVC pipes in poorly ventilated trenches)

·         Vibration and hazardous noise

·         Overhead essential services (power lines) and ground-mounted essential services (transformers, gas, and water meters).

 

Controlling the risks

·         Substitution – for example using an excavator with a rock breaker rather than the manual method

·         Isolation – for example using concrete barriers to separate pedestrians and powered mobile plant to reduce the risk of collision.

·         Engineering Controls – for example, benching, battering, or shoring the sides of the excavation to reduce the risk of ground collapse.

·         If risk remains, it must be minimized by implementing administrative controls, so far as is reasonably practicable, for example by installing warning signs near the excavation.

·         Any remaining risk must be minimized with suitable personal protective equipment (PPE), such as providing workers with hard hats, hearing protectors, and high visibility vests.

·         Administrative control measures and PPE rely on human behavior and supervision and used on their own tend to be the least effective in minimizing risks.