Definition - What does Trench Box mean?
A trench box is a safety device used to protect workers in trenches. It is a square structure made up of pre-constructed side sheets and adjustable cross members. It is usually made of steel or aluminum. Trench boxes are critical to the safety of workers working below ground as a trench collapse can be fatal.
Trench boxes may also be referred to as sewer boxes, manhole boxes, trench shields, trench sheets, or tap boxes.
Trenchlesspedia explains Trench Box
Workers in trench construction should take every precaution to prevent collapse and ensure safety. OSHA rules require trench boxes to protect workers involved in trenching and excavation. Anyone doing this work must follow specific standards of safety outlined in OSHA Safety and Health Regulations for Construction, Subpart P, titled “Excavations.” Trench boxes and other safety measures may also be required in insertion or reception pits of trenchless construction.
Trench boxes are usually constructed onsite using an excavator or other heavy-duty equipment. First, a steel or aluminum sidesheet is laid on the ground. Spreaders (usually four) are attached to the sidesheet. With the four spreaders extending vertically, another sidesheet is attached on top. Then the structure is turned upright. Now rigging is attached to the box and it is lifted and placed into the trench. A guidewire may be used by a worker to align the trench box to the hole.
The primary reason for a trench box is the safety of workers while they are in the trench. Trench shoring is a related term that refers to the process of bracing the walls of an entire trench to prevent collapse. Companies doing this work are responsible for the safety of employees and are liable for any negligent mishaps.