20 Mar Excavation/Trenching Safety
Each year excavation and trenching cave-ins result in more than 5,000 serious injuries and 100 deaths in the United States. The key to prevention of this type of loss is good planning. When the side of a trench decides to move it is too late to be thinking about your safety or the safety of others. Here are some good safety rules and practices to follow when working in or around excavations.
- Evaluation of shoring, sloping, or other means to eliminate the potential for cave-ins must be performed prior to the start of work. Consider these engineering controls at the pre-bid stage:
- The costs associated with some systems may significantly reduce or eliminate the profit of a job if not considered at the time of the bid. The evaluation must be performed by a trained person who is knowledgeable in the areas of soil analysis, the use of protective systems, and in the requirements of applicable standards and regulations. Without this pre-job planning, project foremen may be inclined to “make-do” just to get the job done. Shortcuts might be taken, putting employees in significant danger. Perform these pre-job procedures regardless of the duration of the project or because the ground “just looks solid.”
- Work in an excavation or trench must at all times be under the immediate supervision of a qualified person.
- Excavated material must be placed at least 2 feet from the edge of any trench or excavation, which is 4 or more feet in depth.
- Adequate precautions must be taken to ensure that vibrating equipment and vehicular traffic do not cause a cave-in.
- Always consider groundwater seepage as a potential cause of the collapse of any trench or excavation.
- Safe access/egress must be provided (stairway, ladder, ramp, etc.). The equipment must be securely fastened in place. Access must be provided and located so no worker must laterally travel more than 25 feet to access the egress point in any trench or excavation deeper than four feet.
There are specific standards for the materials used for shoring, and for the angles of slopes used to protect workers. All the protection methods depend on the composition of the soil. Contact your company’s excavation competent person for more specific information.
If you aren’t certain that the shoring, benching, or sloping is adequate, stay out of the excavation. Entering an unprotected excavation or trench may be the last thing you ever do.