Trenches can be a dangerous part of excavation projects due to the unstable nature of rock and soil. Fortunately, many of the dangers associated with trenches are preventable with the right training and equipment. Trench boxes, also known as trench shields, are a necessary and important part of any excavation work site. Read on to learn more about why you need a trench box at your site.
What Is the Purpose of a Trench Shield?
Trench boxes are strong structures that fit inside unsloped, narrow work trenches and provide a protective shelter for those working inside. You use a trench shield at excavation sites where trenchless options aren’t possible. Many site managers prefer trench shields over total soil removal because installing trench boxes is usually more cost-effective and provides reliable support.
Compared to manhole boxes, which have four solid walls that completely enclose workers, a trench shield consists of adjustable, durable plate walls and bars that can keep workers safe in the event of a trench collapse. They are especially useful in areas with loose soil or when working through rainy conditions, as they provide a quick and safe way for workers to exit the trench in case of emergency.
How Do Trench Boxes Work?
Though trench shields improve the stability of the earth inside and surrounding the trench, they do not prevent trench collapse or shifting soil entirely. The purpose of a trench box is to offer a strong, protective barrier for the workers inside. They have adjustable spreaders that you can adapt to your specific work site and trench size. Trench boxes should also have a ladder or similar way for workers to enter and exit safely. Because they offer convenient access in and out of the trench, trench shields can also increase productivity around the work site and help workers complete tasks faster.
Different Types of Trench Boxes
Trench boxes are usually made of aluminum, steel or both, making them long-lasting and weather-resistant. Aluminum and steel construction also means the trench shield will not warp, corrode or bend over time. When it comes to steel vs. aluminum trench boxes, your decision should come down to the type of terrain you’re working in and the scale of your project:
- Aluminum trench boxes: Aluminum trench boxes are perfect for shallow earth or small-scale jobs because they are lightweight and simple to move and store. They are lighter than steel, and some are stackable.
- Steel trench boxes: Steel trench boxes are heavier than their aluminum counterparts, but the additional weight makes them very durable for challenging terrain or large-scale projects.
In addition to different materials, there are also different types of trench shields, depending on your project needs. Some common trench boxes you might find at an excavation site include:
- Mini- and standard-sized trench boxes: Trench boxes are available in different sizes, including mini and standard. Some manufacturers also produce mega versions for larger jobs and steeper trenches.
- Backhoe trench and backhoe drag trench boxes: Standard backhoe trench boxes are for work sites that rely on small excavators to complete projects. Backhoe drag boxes are for the same thing, except you can drag and move them as the project grows.
- Rolling strut trench boxes: Rolling strut trench boxes make installing your shield easier because they allow the plate boxes to move.
- Super drag trench boxes: Super drag trench boxes are different from regular trench shields because they are not intended to support the entirety of a trench’s walls. Instead, their built-in panels are movable and suitable for self-supporting soil.
For the safety of you and all site workers, make sure you choose the trench shield that is compatible with your soil conditions and type of project before installation. Work with a contractor to ensure proper installation and OSHA compliance.
Who Uses Trench Boxes?
Anyone who works at an excavation site where trenching alternatives are not an option should be using trench shields for protection. As of 2017, trenches were responsible for an average of 19 construction-related fatalities per year in the United States — not to mention the injuries and damaged equipment that can result from a trench collapse. Even a small amount of soil can move quickly and weigh more than 3,000 pounds. For this reason, working in unprotected trenches is dangerous and unnecessary.
Trench boxes are not only a good idea around excavation sites — they are a requirement. According to OSHA 1926.652, all employees must have adequate protection when working in excavated areas that are 5 feet deep or more, and sometimes in shallower conditions. Additionally, all trench boxes must:
- Extend 18 inches above the surface of the soil.
- Be no more than 2 feet from the bottom of the trench when combined with sloping.
- Be designed by a certified professional if the trench exceeds 20 feet deep.
- Be strong enough to withstand the depth pressure and type of soil you install them in.
You can use some trench shields alongside other protective barrier methods, like sloping. When you use a trench box, OSHA also requires that a contractor inspect all excavation sites before beginning a project to examine and classify the soil content, so they can use the appropriate sloping methods to maximize safety.
Find Trench Boxes at Ohio Cat Rental Store
If you’re preparing for an excavation or trench shoring project, Ohio Cat Rental Store has the aluminum and steel trench shields you need for the job. We’re a family-owned business that has proudly provided quality Cat® equipment to all of Ohio and parts of Indiana and Kentucky for nearly 75 years.
When you rent with Ohio Cat Rental Store, you get access to an extensive inventory of both aluminum and steel trench shields in a variety of size options, as well as manhole shields and stacker units. With decades of experience in the industry, we can help you choose the right trench box for your project needs at a competitive price.