Difference Between Excavation And Trench

Trenching and excavation work presents serious hazards to all workers involved. Cave-ins pose the greatest risk and are more likely than some other excavation-related incidents to result in worker fatalities. One cubic yard of soil can weigh as much as a car. Employers must ensure that workers enter trenches only after adequate protections are in place to address cave-in hazards. Other potential hazards associated with trenching work include falling loads, hazardous atmospheres, and hazards from mobile equipment.

Excavation vs Trench

Dig a hole in the ground and you’ve made an excavation. Excavations can be any size: wide, narrow, deep, or shallow.

A trench is a narrow excavation, not more than 15 feet wide at the bottom. If you install forms or other structures in an excavation that reduce its width to less than 15 feet, measured at the bottom, the excavation is also considered a trench.

• If you work in an excavation that’s five feet deep (or deeper) you must be protected from a cave-in.
• If a competent person, who has training in soil analysis, determines that there’s a potential for an excavation to cave-in, you must be protected regardless of its depth.

The dangers of trenching and excavation operations

Trenching and excavation work presents serious hazards to all workers involved. Cave-ins pose the greatest risk and are more likely than some other excavation-related incidents to result in worker fatalities. One cubic yard of soil can weigh as much as a car. An unprotected trench can be an early grave. Employers must ensure that workers enter trenches only after adequate protections are in place to address cave-in hazards. Other potential hazards associated with trenching work include falling loads, hazardous atmospheres, and hazards from mobile equipment.

What do the OSHA Excavation standards cover, and how do they protect workers?

The standards apply to all open excavations made on the Earth’s surface, including trenches. Following the requirements of the standards will prevent or greatly reduce the risk of cave-ins and other excavation-related incidents.

Why is preplanning important to excavation work?

No matter how many trenching, shoring, and backfilling jobs an employer has done in the past, it is important to approach each new job with care and preparation. Many on-the-job incidents result from inadequate initial planning. Waiting until after the Occupational Safety and Health Administration 4 work starts to correct mistakes in shoring or sloping slows down the operation, adds to the cost of the project, and makes a cave-in or other excavation failure more likely.

How can employers prevent cave-ins?

OSHA generally requires that employers protect workers from cave-ins by:

• Sloping and benching the sides of the excavation;
• Supporting the sides of the excavation; or
• Placing a shield between the side of the excavation and the work area.

The requirements for safely installing and removing protective systems

The Excavation standards require employers to take certain steps to protect workers when installing and removing support systems. For example:

• Members of support systems must be securely connected to prevent sliding, falling, kickouts or predictable failure.
• Support systems must be installed and removed in a manner that protects workers from cave-ins and structural collapses and from being struck by members of the support system.
• Members of support systems must not be overloaded.
• Before temporary removal of individual members, additional precautions are required, such as installing other structural members to carry loads imposed on the support system.
• Removal must begin at, and progress from, the bottom of the excavation.
• Backfilling must progress together with the removal of support systems from excavations.

In addition, the standards permit excavation of 2 feet (0.61 meters) or less below the bottom of the members of a support system, but only if the system is designed to resist the forces calculated for the full depth of the trench and there are no indications, while the trench is open, of a possible loss of soil from behind or below the bottom of the support system. Employers must coordinate the installation of support systems with the excavation work.