Access and Egress
OSHA standards require safe access and egress to all excavations, including ladders, steps, ramps, or other safe means of exit for employees working in trench excavations 4 feet (1.22 meters) or deeper. These devices must be located within 25 feet (7.6 meters) of all workers.
General Trenching and Excavation Rules
• Keep heavy equipment away from trench edges.
• Identify other sources that might affect trench stability.
• Keep excavated soil (spoils) and other materials at least 2 feet (0.6 meters) from trench edges.
• Know where underground utilities are located before digging.
• Test for atmospheric hazards such as low oxygen, hazardous fumes and toxic gases when > 4 feet deep.
• Inspect trenches at the start of each shift.
• Inspect trenches following a rainstorm or other water intrusion.
• Do not work under suspended or raised loads and materials.
• Inspect trenches after any occurrence that could have changed conditions in the trench.
• Ensure that personnel wear high visibility or other suitable clothing when exposed to vehicular traffic.
Protective Systems
There are different types of protective systems. Benching means a method of protecting workers from cave-ins by excavating the sides of anexcavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels. Benching cannot be done inType C soil. Sloping involves cutting back the trench wall at an angle inclined away from the excavation. Shoring requires installing aluminum hydraulic or other types of supports to prevent soil movement and cave-ins. Shielding protects workers by using trench boxes or other types of supports to prevent soil cave-ins. Designing a protective system can be complex because you must consider many factors: soil classification, depth of cut, water content of soil, changes caused by weather or climate, surcharge loads (e.g., spoil, other materials to be used in the trench) and other operations in the vicinity.
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