Many excavation projects require workers to operate in and around trenches, which are some of the most dangerous areas on a work site. Trenches are prone to collapsing, and that makes them a monumental hazard to the crew. If a trench collapse occurs while one or more workers are inside, there’s a major risk for severe injury and death. For this very reason, shoring boxes are implemented at various excavation sites and have become a fundamental element of supporting both safety and efficiency.
In this article, we’re explaining what shoring boxes are, what advantages they bring to an excavation project and what you need to know about applying them safely and effectively.
What Are Shoring Boxes?
OSHA requires construction crews to implement protective systems for trenches that have a depth of five feet or more, or those involving soil conditions that are conducive to cave-ins, as evaluated by a competent individual. One type of protective system is that of trench shoring boxes, which are sometimes also referred to as trench shields, trench sheets, manhole boxes or tap boxes. They are designed for the sole purpose of shielding workers from the life-threatening pressure and weight of soil that can topple when a trench cave-in unfolds.
Typically constructed from aluminum or steel, shoring boxes comprise two plates, or shields, held apart by spreaders, or beams situated perpendicular to the plates in order to brace them. These parts are welded together and function cohesively to allow worker entry and egress. Shoring box components come in varying lengths and thicknesses, and are brought to the excavation project for on-site assembly. The boxes may be built at ground level and then positioned inside the trench by a mechanical excavator and sunk using a hydrovac truck.
Given that one cubic yard of soil can weigh almost as much as a whole car, shoring boxes must be built to withstand immense earth pressure. A trench box’s design determines its soil pressures and depth ratings, and OSHA has outlined specific regulations for proper installation and use.
What Are the Efficiency & Safety Benefits of Shoring Boxes?
Trench-collapse deaths among construction workers have been rising since 2018, and a breakdown of construction trench fatalities between 2003 and 2020 shows that outside of 2016 (which had a decade-high of 33 trench deaths), 2019 and 2020 are tied for the second-deadliest years since 2010. The leading cause of the collapses has been inadequate cave-in protection. Of the 12 deadly collapses in 2020 that have so far resulted in violations, eight were cited for inadequate cave-in protection, and some prosecutors have lodged criminal charges in trench death cases.
The fatality rate for excavation work is 112 percent higher than the rate for general construction, and OSHA fines for trenching violations range from tens to hundreds of thousands of dollars. So when excavation crews take shortcuts and fail to implement proper shoring box systems, they put the lives of the workers at severe risk, potentially incurring serious liability and causing major delays or added costs to the project at large.
The truth is even when all the proper safety precautions are taken, trench cave-ins can still occur. Trench shoring boxes provide that extra layer of safety and security for the workers operating inside, thereby minimizing their risk of injury or death. Shoring box systems also help bolster the stability of the trench, and make it faster and easier for workers to access and exit the area. Workers who feel protected within the trench shoring boxes are less likely to rush or make unnecessary mistakes as a result of preoccupation with the hazards at hand. These boxes can be extremely valuable for keeping excavation projects safe, efficient and cost effective, and for maintaining compliance with OSHA regulations.
What Does OSHA Require for Installation, Removal & Maintenance?
OSHA’s Excavation standards require employers to take certain steps to protect workers when installing and removing support systems like shoring boxes. 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.
Employers are also responsible for maintaining materials and equipment used for protective
Systems like shoring boxes. Because defective and damaged materials and equipment can cause protective systems to fail and lead to other excavation hazards, employers must ensure that:
- Materials and equipment are free from damage or defects that might impair their proper function
- Manufactured materials and equipment are used and maintained consistent with the manufacturer’s recommendations and are used so as to prevent worker exposure to hazards
- A competent person examines any damaged materials or equipment to evaluate its suitability for continued use
- If a competent person cannot assure that damaged material or equipment can support the intended loads or is otherwise suitable for use, the materials and equipment are removed from service until evaluated and approved by a registered professional engineer
Given these critical requirements and the enormous hazards associated with excavation projects in general, it is essential to partner with a professional construction team that has experience implementing shoring boxes and other vital safety precautions. Because these efforts must be handled competently and thoroughly by highly skilled, trained professionals who prioritize safety above all else, opt to contract the services of a qualified team who can bring the highest standards of safety and efficiency to your project.
Before starting your next project, be sure to view our free brochure to learn more about our services.