Shield systems shall not be subjected to loads exceeding those which the system was designed to withstand.
Employees shall be protected from the hazard of cave-ins when entering or exiting the areas protected by shields.
Employees shall not be allowed in shields when shields are being installed, removed, or moved vertically.
Shields shall be installed in a manner to restrict lateral or other hazardous movement of the shield in the event of the application of sudden lateral loads.
Excavations of earth material to a level not greater than 2 feet (.61 m) below the bottom of a shield shall be permitted, but only if the shield is designed to resist the forces calculated for the full depth of the trench, and there are no indications while the trench is open of a possible loss of soil from behind or below the bottom of the shield.