Excavation represents one of the most dangerous activities on a construction site. Contractors working on excavation projects face dangers from underground power lines, poor air quality, and even the risk of a collapsed trench. To reduce these risks, contractors should follow governmental and industry safety regulations, appoint safety officers, and train their workers. Safe excavation sites generally use proper support and shoring strategies for holes, and make sure workers can safely exit excavation projects.
In the United States (US), builders must follow federal excavation safety standards. These standards are developed and enforced by the Occupational Safety and Health Administration (OSHA). Many other developed nations have similar safety plans in place to protect workers during an excavation project.
One of the biggest dangers facing workers during excavation is the risk of a cave-in or trench collapse. To reduce this danger, builders must take steps to create a safer trench and use proper support devices. The shape and size of the trench should be based on soil conditions at the site, which requires soil testing prior to digging. Walls should be supported using hydraulic cylinders, jacks, or trench shields when soil conditions are very poor. As soil is removed from the trench, it should be safely stored away from the opening so that it can't fall back into the hole.
The top of the trench should be well marked to prevent falls from people or equipment. Rails and fences can also improve excavation safety for those above and below the ground. Workers should have a clear path around the excavation site to avoid the risk of falling or dropping tools into the hole.
Effective excavation safety also requires safe egress for those working underground. When a hole grows too deep for individuals to reasonably climb out unassisted, stairs or ladders must be added. These means of egress must be placed at accessible intervals along the trench so that all workers can exit quickly during an emergency.
To reduce the risk of electrical shock or fire from an underground electrical line, contractors should notify the local utility company before digging. The company can inform the builder about any utility lines on the project site, and may even mark the lines to prevent accidental damage. While digging close to these lines, builders can maximize excavation safety by replacing machines with hand digging.
One of the most effective ways to maximize excavation safety is to assign an individual to design and maintain all safety systems on the project. An engineer or safety specialist can perform regular soil testing and adjust the system as needed. All shoring devices, fences, and egress paths should also be inspected daily to check for damage. Finally, all workers should be trained on the different excavation safety methods in use on the project.