National Center for Construction Education & Research (NCCER) Plumbing Level 1 Practice Exam

Installing a trench shield is essential for protecting workers from the collapse of an unshored excavation wall. A trench shield, also known as a trench box, is a protective structure that provides a safe working environment in trenching operations. It is designed to prevent soil from caving in and offers physical protection to workers who are working in or near the excavation.

Trench shields are typically made of steel or aluminum and are installed in the trench to support the walls, allowing workers to safely enter and exit the site without the risk of soil collapse. By using trench shields, the integrity of the excavation walls is maintained, and the safety of the workers is significantly increased.

Other options like support beams, safety nets, and scaffolding do not provide the necessary protection specifically for trench excavations. Support beams may be useful in other construction contexts but may not be appropriate for preventing collapse in a trench environment. Safety nets are primarily used to catch falling objects rather than preventing wall collapses. Scaffolding is intended for providing access and support for workers but does not serve the function of stabilizing trench walls. Therefore, the trench shield is the most suitable choice for this specific safety need in excavation work.