In order to construct and/or repair roads, bridges, and other types of building projects, workers often need to excavate. As a result, these trenches will require temporary shoring methods.
Excavation Basics
An excavation, according to the Occupational Safety and Health Administration (OSHA), is “any man-made cut, cavity, trench, or depression in the earth?s surface formed by earth removal.” Trenches, however, are narrow, underground excavations which are deeper than they are wide. As defined by OSHA, they are no more than 15 feet across.
Different Types of Shoring for Excavation
Timber and aluminum hydraulic are the 2 basic types of shoring materials used for excavation purposes. In open areas, trench boxes, or excavation shoring boxes, tend to be used. In some instances, excavation shoring boxes may be used in conjunction with sloping and benching.
When there is sloping toward an excavation, it is recommended that an excavation shoring box should extend a minimum of 18 inches above the surrounding area. A benched area can be provided next to the box in order to accomplish this task.
Shoring Safety Measures and Protective Systems
When digging trenches, the excavated soil and other materials need to be piled a minimum of 2 feet away from the edge of the trench. This is an important measure to take because it prevents these materials from falling back into the trench. Furthermore, if any equipment is located nearby, it prevents it from rolling or falling into the trench.
When trenches are over 4 feet deep, there’s a possibility of encountering hazardous fumes and topic gases. Low oxygen levels are also possible. As a result, it’s important to test for possible atmospheric hazards before working in the trench.
Protective systems are required when trenches are 5 or more feet deep. The exception to this requirement is when the excavation is taking place in stable rock.
When trenches are 20 or more feet deep, the protective system needs to be specifically designed by a registered professional engineer in order to maintain safety regulations. The exceptions to this would be when the system is based on prior data and/or approved by a registered professional engineer.
Providing Safe Access and Egress
The ability to have safe access and egress to an excavation site is also required by OSHA. This includes having the appropriate measures in place for workers to safely exit a trench excavation. When a trench is 4 or more feet deep, ladders, steps, ramps and other devices are required. In order to have easy access to these devices, OSHA mandates that they should be kept no more than 25 feet away from workers at all times.
