Excavations are recognized as one of the most hazardous operations in the construction industry. Excavation cave-ins can cause serious and often fatal injuries to employees. In addition to the hazards related to cave-ins, excavations are of particular concern due to the complex underground utility infrastructure. OSHA places very strict regulations governing the design of an excavation, cave-in prevention methods, and employee training.
Requirements for All Excavations
- An underground utility survey must be conducted prior to the start of any excavation. Call 811 before you dig
- All employees working in an excavation must receive initial training
- A competent person must be clearly identified for all excavations. This person must be knowledgeable in assessing soil conditions, the use of protective systems, and OSHA requirements
- The soil type must be identified by the competent person on site:
- Type A – clay, silty clay, sandy clay, clay loam and cemented soils (hardpan)
- Type B – angular gravel, silt, silt loam, and sandy loam
- Type C – gravel, sand, and loamy sand
- Excavated material must be placed at least 2 feet from the edge of any excavation
- Precautions must be taken to ensure vibrating equipment/vehicular traffic does not cause a cave-in
- No employee shall enter an excavation that contains standing or seeping water
- Access (ladder/ramp) must be provided and located so no worker must travel more than 25 feet to exit
- Employees at the edge of an excavation 6 feet or more in depth shall be protected from falling
- If conditions change in or around the excavation, employees must exit the excavation and a competent person must re-inspect and give approval for employees to re-enter.
Excavations 5 Ft. Or Greater in Depth
- Sloping, benching, or other approved cave-in protection systems must be utilized
- Trench boxes/shoring must be a designed and approved system
- The trench box should extend at least 18 inches above the surrounding ground surface
- Excavations greater than 20 feet must be designed by an engineer.