Moving & Setting Trench Boxes
Trench boxes protect workers when they are used right, but the moments when the box is lifted, slid or removed are among the most dangerous. People have been crushed by boxes dropping or moving, and buried when soil collapsed during setup.
- Utility Crews
- Excavator Operators
- Competent Persons
Rules that apply
- Employees are not allowed in the trench while a shield is being installed, removed or moved vertically (1926.652(g)(1)(iv) and (g)(1)(iii), which require that employees be protected from cave-ins and that shield systems be installed to prevent lateral movement).
- Follow the manufacturer's tabulated data. See Manufacturer Tabulated Data.
- The box must be used within its depth and soil ratings.
Setting the box
- Check the box for damage, bent struts or cracks before lifting
- Use lifting lugs and rated slings, chains or spreader bars, with equipment rated for the weight (including mud on the box). See Lifting Lugs & Pad Eyes
- Keep everyone clear of the box and equipment swing area while it is lifted
- Lower the box so that the bottom is at or below the cut, and the top extends at least 18 inches above the surrounding ground if the ground slopes away. Make sure it fits the trench width
- Do not excavate more than 2 feet below the bottom of the box unless an engineer designs for it
- Fill voids behind the box with soil or fill that protects from cave-in
Moving
- Get all workers out of the trench and out of the area before moving or dragging the box.
- Lift or slide the box forward in short steps, using a signal person and clear signals.
- Do not move a box with workers inside it, and never use the box as a lift platform.
- Keep the trench ahead of the box short; the unprotected length must be as small as possible and shored or sloped if workers must enter.
- When stacking boxes, use only approved stacking, connection pins and designs for stacks.
- Inspect the box and trench after each move.
Removing
- Backfill in stages as the box is raised, so soil is always supported.
- Remove the box slowly, watching for sloughing. Keep people away.
- A competent person oversees removal. See Competent Person Inspections.
Standards & references
Last updated: