What is the maximum excavation depth allowed below a shield system?

The maximum excavation depth allowed below a shield system is established to ensure the safety and stability of workers in trenches. When using a shield system, the design must protect workers from cave-ins by providing a barrier that can withstand soil pressure.

The specific maximum depth of 2 feet below a shield is crucial because it mitigates risks associated with further excavation under the protective system. By limiting the depth to this measurement, it helps prevent potential soil collapsing and maintains effective protection for workers while they are operating within the trench. This guideline is a part of OSHA regulations related to excavation and trenching, highlighting the importance of safety practices in construction environments.

Other answer choices suggest deeper excavations that exceed the safety threshold defined by OSHA, which could inadvertently increase the risk to workers. Maintaining a 2-foot limit ensures the structural integrity of the shield while providing sufficient space for workers to conduct their tasks without unnecessary risk.