#131 TRENCHING AND EXCAVATING
Excavations and trenches need not be deep or large to create a life-threatening hazard. Soil is heavy, and failures take place with little or no notice. You can be trapped before there is time to react. So it is important that every excavation be prepared correctly, allowing you to complete your job safely and efficiently. Remember that every trench is different. Soil type, moisture content, depth, configuration, proximity to existing structures, and location of spoil piles all work together to make every excavation unique.
- Follow the recommendations of your Competent Person carefully. Their job is to ensure that the excavation is adequately protected so you can complete your task safely.
- ALL trenches and excavations over 5 feet in depth must be protected from cave-ins unless they are made entirely of stable rock. Protection can be provided by adequately sloping back the sides of the cut or by benching the excavation. Trenches can also be reinforced by installing shoring or using trench boxes. If shoring or boxes are used be sure the top of the box extends at least 18 inches above the hole. And remember, if the hole is deeper than 6 feet, fall protection should be installed around the perimeter to protect those working on the surface.
- Spoil piles must stay at least 2 feet back from the edge of the hole. This is measured from the point where the slough of the pile ends. Placing the spoil any closer exerts excessive pressure on the walls of the excavation and thus increases the chance of a wall failure.
- Install ladders, so that no matter which way you travel in the trench, a ladder can be accessed within at least 25 feet.
Remember you are the one going into the hole, so check the methods being used to protect the excavation. Prior to climbing down the ladder, check the spoil pile location and equipment that is near the excavation. Do you feel comfortable with the excavation, its protection, and the nearby surroundings?