Tuesday, November 21, 2006

Excavations

Excavations create a number of hazards closely related to working at height. In particular people can fall into the excavation and things can be dropped on people who are in the hole. There is no specific depth at which an excavation is considered to be dangerous, remembering that someone bending over or kneeling down in a shallow hole could be serious hurt if it collapses.

In addition excavations can become confined spaces, there is the potential for sides to cave in and for contact to be made with underground hazards including buried services and contaminated soil.

Precautions to cave in include angling the sides instead of making them verticle, making sure spoil from digging the excavtion is not left at the side and providing support using timber, sheeting or propriety systems.

The potential for buried services should be identified before starting the excavation. Where this risk is not zero precautions such as detectors/locators and digging of test trenches should be used.

A competent person must inspect excavations:
* At the start of each shift before work begins;
* After any event likely to have affected the strength or stability of the excavation; and
* After any accidental fall of rock, earth or other material.

A written report should be made after most inspections.

Of course there are also hazards associated with the method used to create the excavation. Doing it by hand creates manual handling issues whilst alternative methods usually involve the use of vehicles.

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