When it comes time to lay the foundation of a new home, trenching must be done. Any time the ground must be opened up; there is a risk of a collapse. According to OSHA, trenching work alone is estimated to have a fatality rate that is 112% higher than all other types of construction. There are two factors causing this: 1) many companies do not emphasis safety by taking the necessary precautions 2) cave-ins usually occur without warning. Read the proper Trenching guidelines to help your affiliate follow proper trenching procedures.
- Locate all underground utilities by contacting the local utility locating service before digging.
- Keep workers away from digging equipment and never allow workers in an excavation when equipment is in use.
- Keep workers from getting between equipment in use and other obstacles and machinery that can cause crushing hazards.
- Keep the equipment and the spoil piles back 2 feet form the edge of the excavation.
- Have a competent person conduct daily inspections and correct any hazards before workers enter a trench or excavation.
- Provide workers a way to get into and out of a trench or excavation such as ladders and ramps. They must be within 25 feet of the worker.
- For excavations and utility trenches over 5 feet deep, use shoring, shields (trench boxes), benching, or slope back the sides. Unless a soil analysis has been completed, the earth’s slope must be at least 1 ½ feet horizontal to 1 foot vertical.
- Keep water out of trenches with a pump or drainage system, and inspect the area for soil movement and potential cave-ins.
- Keep drivers in the cab and workers away from dump trucks when dirt and other debris are being loaded into them. Don’t allow workers under any load and train them to stay clear of the backs of vehicles.
- After the foundation walls are constructed, take special precautions to prevent injury from cave-ins in the area between the excavation wall and the foundation wall.
- The depth of the foundation/basement trench cannot exceed 7 ½ feet deep unless you provide other cave-in protection.
- Keep the horizontal width of the foundation trench at least 2 feet wide. Make sure no work activity vibrates the soil while workers are in the trench.
- Plan the foundation trench work to minimize the number of workers in the trench and the length of time they spend in there.
- Inspect the trench regularly for changes in the stability of the earth. Stop work if any potential for cave-in develops and fix the problem before work starts again.
Take charge, and make sure your volunteers and employees understand, and practice, these trenching guidelines.
And remember to always get a signed waiver from all volunteers prior to them working on the jobsite! If you have any questions please call the Habitat for Humanity Affiliate Insurance Program at (888) 553-9002.