National Trench Safety introduced the Lite GuardTM Aluminum Shield last spring and has begun the process of manufacturing and deploying the shield to NTS branch locations. The Lite GuardTM, composed of a proprietary aluminum extruded panel, provides depth ratings comparable to that of a steel trench shield at about a third the weight (see Exhibit 1 for representative depth ratings).
A recent project in Northern Virginia showcased the capabilities of the shield over existing alternatives. A contractor was installing a new water line that will feed development within a large city, including business park and apartments. In the past, the contractor would have customarily used a steel trench shield for this project, however, the Lite GuardTM shield provided the necessary depth rating for the project, but severely reduced the requirement for heavier lifting machinery on site. In applications like these, steel trench shields can provide longer open span lengths for the easy installation of large pipe joints, as well as having the flexibility to drag the trench shield along the production run.
The contractor elected to use an 8′ x 24′ Lite GuardTM aluminum shield for the linear runs and a steel manhole shield to perform the manhole tie-ins for the project. After reviewing the specifications for the Lite GuardTM alongside those of a steel trench shield, the contractor was able to achieve the same functionality, while significantly decreasing the weight of the system. The contractor was very impressed with the strength and versatility of the Lite GuardTM aluminum shield and its potential to reduce the requirement for heavier machinery solely as a means to lift heavier steel trench shields.
This project highlights the benefit of having an aluminum shield that can support longer joints of pipe. Most conventional aluminum shielding products available today do not have the strength to be able to support 24-ft spans without severely sacrificing the weight benefits of using aluminum. Additionally, most aluminum shields are especially prone to damage as aluminum is a softer metal not designed to be drug along a trench. The Lite GuardTM features a unique hardened aluminum knife edge that allows the shield to be much more resilient than traditional aluminum trench shields when used in production applications.