Final answer:
When using a trench box with sloping or benching techniques, it should extend at least 18 inches above the adjacent slope to ensure worker safety. This follows OSHA guidelines to prevent soil collapses and protect workers in trenches.
Step-by-step explanation:
When using a trench box in combination with sloping or benching, the trench box should extend at least 18 inches (46 centimeters) above the adjacent slope. This safety measure is essential to protect workers from soil collapse or material that could fall inside the trench. It is crucial to follow OSHA regulations and guidelines when constructing and using trench boxes, as well as while performing the procedures of sloping or benching.
Trench boxes, also known as trench shields, are designed to safeguard employees within the confines of a trench. When they are used in combination with sloping or benching, which are methods of cutting back the trench wall at an angle inclined away from the excavation, appropriate measures must be taken to ensure stability and safety. The rule of having the trench box extend a minimum of 18 inches above the slope is designed to provide an added layer of protection against cave-ins and the rolling in of materials from the adjacent area.