Construction work is one of the most dangerous occupations in the nation. Every shift, workers are required to use heavy machinery, drive large vehicles and handle dangerous materials. In addition to working atop ladders and scaffolds, it sometimes becomes necessary to work in trenches several feet deep. When these trenches collapse, however, construction workers can face devastating injuries or even death.
What can be done to prevent a trench collapse?
There are numerous reasons why an excavation might be necessary on a construction site, but there are several steps that should be followed to ensure the safety of all workers. OSHA defines a trench as a narrow underground excavation that is deeper than it is wide and is no wider than 15 feet. What safety precautions do they recommend?
- Be aware: Never enter an unprotected trench. A trench that is five feet deep or greater requires a protective system unless the excavation is made entirely in stable rock. If the trench is 20 feet deep or greater, the protective system must be designed by a registered professional engineer. Failing that, the system must be based on data prepared or approved by a registered professional engineer.
- Protective systems: There are generally three different types of protective systems for excavations: sloping, shoring and shielding. Sloping involves cutting back the trench wall at an angle inclined away from the excavation. Shoring involves installing hydraulics or other types of supports to prevent cave-ins. Shielding involves using a trench box inside the trench to prevent cave-ins.
- Competent person: OSHA standards require the trench be inspected daily by a competent person. This individual might also be required to inspect the trench multiple times a day if conditions change. The competent person must be able to identify existing and predictable hazards. In addition, the competent person must be able to identify hazardous, unsanitary or dangerous working conditions and must be authorized to take prompt corrective measures.
In a trench or other type of excavation, a cave-in is the greatest risk. While a cave-in might result in a worker fatality, it is not the only dangerous work injury. Workers can be injured from a wide array of hazards including falls, falling loads, hazardous atmospheres and incidents involving mobile equipment.