Increasing Safety . . . During Public Works Projects
How can water under high pressure assist with making public works’ projects safer? The answer may be simpler than you would expect. As a project is in the planning stages, even before digging occurs, the application of a strong jet of water can confirm the location and expose the presence of existing underground facilities. Not only does this aid with protecting the integrity of the equipment that is in place, but it also ensures the safety of the workers as the project moves forward.
The process of excavation by water is simple. A truck capable of storing water and excavated material that can also produce a water stream at variable safe working pressures up to 3000 psi is moved to the area. Workers then use a lance that directs a controlled spray of water at the dirt, loosening it, while simultaneously vacuuming the dislodged material from the hole through a tube. Once the facility has been exposed, if one is present, it can be safely unearthed by vacuum means or its exact location and depth can be determined and mapped. Water excavation can be used for very shallow excavations or to depths of more than 30 feet. It is also used in areas with highly congested facilities as the sole method of trenching for new facility installation.
The use of this process minimizes contact with any underground facility thereby preventing a line from being severed, scratched or punctured. There are a number of other benefits that apply to this procedure and to the general vacuum excavation process overall. One obvious advantage is that of increased safety. Another is that it is relatively cost effective. While the amount of savings is tabulated more on a per hour basis, the numbers of hours required to complete an excavation, and the precision of the excavation itself is far greater than what can be achieved through manual labor. Excavation with water is also much faster and has the capability to reach depths and into areas that would inaccessible or too difficult to penetrate by using a shovel or even heavy equipment. Many of the hydro excavating companies also require extensive training programs for their employees in occupational and excavation safety along with damage prevention, emergency response procedures and the application of first aid.
Underground facilities operators and state laws have always required that person seeking to dig make a one-call prior to beginning their excavation work. The system is simple and usually free. Dialing 811, the national one-call notification number, allows the person to state the location of the proposed excavation and, in turn, the facility operator can then mark the facility if it is near the vicinity of the proposed dig. While this process assists with notifying all project stakeholders that an excavation is occurring, it does not necessarily ensure the safety of the facility once excavation begins.
In their review of project proposals, municipalities, counties and even state departments of transportation are now taking into serious consideration exactly how it is that contractors plan to address the existence of underground facilities. Requests for bids or project contracts that require contractors to use hydro (water) or vacuum excavation must contain specific provisions for the protection of any and all existing underground systems.