Shieldingf

Shielding with a trench box can protect the workers in a trench from cave in.Trench box are different from shoring. Instead  of shoring up or otherwise supporting the trench face ,They are intended primarily to shield workers from cave in and similar incidents.The excavated area beet ween the out side of the trench box and  the face of the trench should be as small as possible.The space between    trench box and the excavation side are back filled to prevent  lateral movement of the box.Shields may not be subjected to load exceeding those which the system was designed to withstand.