Excavation and Trenching PRESENTED BY Did You Know
Excavation and Trenching PRESENTED BY
Did You Know? The fatality rate for excavation work is 112% higher than the rate for general construction.
Excavation vs Trench • An excavation as any man-made cut, cavity, trench, or depression in the Earth’s surface formed by earth removal. • A trench is defined as a narrow excavation (in relation to its length) made below the surface of the ground. • Generally, the depth of a trench is greater than its width, but the width of a trench (measured at the bottom) is not greater than 15 feet.
Before You Begin Know as much as possible about the jobsite and the materials needed to perform the work safely. Consider may include: • Traffic • Nearby structures • Soil classification • Surface and ground water • Overhead and underground utilities • Weather • Shoring or protective systems • Fall protection needs
Excavation Hazards • Cave In • Hazardous Atmosphere • Falling Loads • Hazards from mobile equipment The primary hazard of trenching and excavation cave in which causes injury or death.
Additional Hazards Include: • Working with heavy machinery • Manual handling of materials • Working in proximity to traffic • Electrical hazards from overhead and underground power-lines • Underground utilities, such as natural gas
Safe work Practices: • Call 811. Know where underground utilities are located before digging. • Keep excavated soil and other materials at least 2 feet from edges. • Keep heavy equipment away from edges. • Identify any equipment or activities that could affect stability. • Test for atmospheric hazards such as low oxygen, hazardous fumes, and toxic gases when workers are more than 4 feet deep. • Inspect trenches at the start of each shift, following a rainstorm or other water intrusion and after any occurrence that could have changed conditions in the trench. • Do not work under suspended or raised loads and materials. • Ensure that personnel wear high-visibility or other suitable clothing when exposed to vehicular traffic
Protective Systems • If the trench or excavation is 5 feet deep or greater, than a protective system is required. • Any excavation or trench that is 20 feet deep or more require a protective system be designed by a registered professional engineer and/ or approved by a registered professional engineer.
Cave In Prevention: Sloping involves angling the walls of the excavation
Cave In Prevention: Shoring requires installing aluminum hydraulic or other supports to prevent soil movement and cave ins.
Cave In Prevention: Shielding protects workers by using trench boxes or ready-made protective systems to prevent soil caveins. (Soil needs to be back filled up to the wall to prevent shifting or collapse of the trench box. )
To Prevent a Cave In: Perform a soil analysis in order to determine appropriate sloping, benching, and shoring. Video: https: //www. osha. gov/dts/vtools/construction/soil_testing_fnl_eng_web. html
Safe Means of Exit For workers working in trench excavations 4 feet or deeper: • OSHA requires employers to provide ladders, steps, ramps, or other safe means of egress • Exit must be located so as not to require workers to travel more than 25 feet to the exit.
Competent Person Responsibilities: A competent person is: • Capable of identifying existing and predictable hazards in the surroundings or working conditions. • Authorized to take prompt corrective measures to eliminate them. Under the Excavation standards, tasks performed by the competent person include: • Classifying soil • Inspecting protective systems • Designing structural ramps • Monitoring water removal equipment • Conducting site inspections
For More Information: http: //www. osha. gov/SLTC/trenchingexcavation/ index. html
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