Safety in shallow trenches

The main risk profile for pedestrian trenchers focuses on underground services -electrical cables, pipes and gas mains- as well as the danger to the operator involved in removing obstructions.

It is important, however, not to forget the trench the machine is leaving in its wake.

The Health and Safety executive makes clear that there is no automatically safe minimum depth of excavation. Pedestrian trenchers can excavate to a maximum of 900mm, and fatal accidents have been known to occur at around this depth. While the operator is unlikely to be regularly in and out of the trench, the following points should be noted to ensure a safe working environment:

• Any depth of excavation is at risk of collapse. The depth is just one factor alongside ground conditions, weather conditions and adjacent works on site.
• Collapse can lead to serious injury at shallow depths. If worker is kneeling in a 1m trench they could easily be buried in a collapse.
• Soil is heavier than most people think- one cubic metre of moderately wet soil can weigh 1.3-1.7 tonnes. It doesn’t take much to break limbs or cause other life changing injuries.
• The spoil pile is part of the height of the trench, unless it is at least 2 feet back from the edge.
• The same goes for any plant or equipment on site- it must be at least 2 feet away from the trench or it poses a hazard.
• Be aware of any nearby structures -pavements, walls- that may be undermined by trenching and pose a collapse hazard.
• Fencing or other safety measures to protect members of the public or those involved in other on-site activities should be in place.
• On no account should a worker enter an unsupported trench vulnerable to collapse, for example one filled with water.

These precautions should be taken by a competent person.

If you have need to excavate shallow trenches and are interested in utilising the safest and most efficient machinery in the market, Weller Plant Ltd can offer self-drive or operated hire options.