Trench Hazards

MITIGATING Trench & Excavation Hazards:

Knowledge, Training and Authority are Key

Trenching and excavation is dangerous work, and associated fatalities have been on the rise. In 2016, 23 construction workers died while working in trenches, more than double the number of deaths from the previous year.

Fortunately, trenching and excavation fatalities are entirely preventable, and the Occupational Safety and Health Administration (OSHA) has made it their focus to reduce these fatalities by September 2019.

The single most important precaution to prevent cave-ins when working in trenches is designating a “competent person” and making sure that person is adequately trained to recognize the risks. Designating a competent person to inspect trenches and identify potential hazards isn’t optional; OSHA requires it. That person must have the authority to remove workers from dangerous areas, stop work if necessary and institute corrective measures to keep employees safe.

“The single most important precaution to prevent cave-ins when working in trenches is designating a “competent person” and making sure that person is adequately trained to recognize the risks.”

Knowledge Is Key

The safety of trenching and excavation operations often comes down to the knowledge and diligence of the competent person. That person decides how best to protect workers who will enter the trench by sloping, benching, shielding or shoring.

Among other skills, the person must know how to conduct visual and manual soil tests because all soil, except for stable rock, will collapse. It’s only a matter of time. Evaluating the soil helps contractors choose the right protective solution and ensure that the shield or other chosen solution isn’t placed at a depth that exceeds what the manufacturer designed it to withstand.

Factors that affect the stability of the soil include surcharge loads, traffic from nearby jobsites, the presence of water, vibrations from equipment, and the length of environmental exposure to name a few.

The competent person must also account for adjacent structures and surface encumbrances, such as utility poles near the trench or excavation. Surface encumbrances that might pose a hazard must be supported or removed. An engineer may be needed to provide guidance.

Knowledge of laws such as the minimum distance from the trench lip for the spoil pile is essential. (The minimum distance is two feet as the weight of the spoil pile adds to the surcharge load, which can make the trench walls more unstable.)

Training Resources

Protective solutions have seen significant advancements, and the competent person may not be up to speed if training has not been kept current. OSHA doesn’t dictate how often that training must occur, so it’s the employer’s responsibility to make certain that competent persons are truly competent and qualified by assessing their ability, training, and experience.

For excavation safety training for a competent person, companies can lean on external resources. Beyond covering the general requirements by OSHA, these training resources expose students to solutions that can balance the opportunity for productivity and safety, whether that be lighter weight aluminum shields that offer higher clearance using manufacturer’s tabulated data or more complex solutions that may require engineered sheeting and bracing to allow workers a safe work zone.

Given today’s complex excavations, a manufactured shoring system may not be adequate to ensure the safety of an operation. In these cases, the project requires a site-specific engineering solution.

Protecting the Workers Who Protect Our Infrastructures

As cities have continued to grow, their infrastructures have continued to age, making jobsite safety more complex and increasing the need for a competent person and a good safety program.

Trenching deaths are preventable. Thanks to existing solutions, equipment and training resources, no worker should ever have to be put at risk. We, as an industry, can and must do better. Knowledge and training is an important element to safe trench and excavation work.

Joe Wise is the Regional Customer Training Manager, Trench Safety Region for United Rentals, the nation’s largest provider of trench safety training equipment and training programs.

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