Trench and Excavation Hazards
Excavations and trenches are dangerous. The fatality rate for excavation work is 112% higher than the rate for general construction. With excavation hazards like cave ins and hazardous atmospheres, we have to stay vigilant to prevent incidents and accidents.
What’s the difference between an excavation and a trench?
An excavation as any man-made cut, cavity, trench, or depression. A trench is a narrow excavation (in relation to its length) made below the surface of the ground. So a trench is an excavation but an excavation isn’t always a trench.
So how do we work safe in an excavation?
There are lots of actions items that can reduce risks while working in an excavation. From testing the atmosphere for hazardous gases to performing an inspection every day and after rain storms, we can prevent an accident by knowing the condition of the excavation.
OSHA has requirements for employers including testing for hazardous atmospheres and having a method of escape for workers working in excavations 4 feet or more in depth. Being familiar with the regulations and providing the various tools and equipment can help prevent an accident and prepare you in the event of an accident.
Safe Work Practices to follow:
- Know where underground utilities are located before digging. Call 811.
- 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.
- Provide methods of egress, including ramps. stairs or ladders within 25 of worker’s as a safe means of exit.
- Inspect the excavation every day before work begins, if unsafe conditions are found keep worker’s out until hazardous condition has been corrected.
Who has the responsibility does a competent person have in excavations?
Under the Excavation Standards, a competent person has many responsibilities, including:
- Classifying soil
- Inspecting protective systems
- Designing structural ramps
- Monitoring water removal equipment
- Conducting site inspections
A competent person can identify existing and predictable hazards in the surroundings or working conditions and is authorized to take prompt corrective measures to eliminate them. To learn the difference between a competent person and a qualified person, you can look at our resource page, January 2018 update.
When is a protective system required?
If the trench or excavation is 5 feet deep or greater, 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.
Protective Systems include:
- Sloping involves angling the walls of the excavation.
- Shoring requires installing aluminum hydraulic or other supports to prevent soil movement and cave ins.
- Shielding protects workers by using trench boxes or ready-made protective systems to prevent soil cave-ins. (Soil needs to be back filled up to the wall to prevent shifting or collapse of the trench box.)
When we comply with regulations and implement regulations, we reduce the risks of excavation hazards. If you would like to have a consultation or discuss your project with our safety specialists, contact us today. We provide a variety of services from on site safety to safety awareness training.