Mar 6th, 2012
Safety is a major concern on any project, but the Matthews Elevated Water Storage Tank Project that is being managed by the Lowcountry Resident Office of the Charleston District has a much higher percentage of potentially catastrophic risk and exposure than most of the construction work handled by the District. The primary focus is on fall protection for contractors as well as for any employees involved in the quality assurance inspections of this free-standing, 185-foot-high structure.
The Matthews Elevated Water Storage Tank is a one million gallon, composite, elevated tank that has a high-water level approximately 180 feet above existing ground level in Cameron, SC and is a part of the $60 million Lake Marion regional Water System Project. This $2.5 million facility is being constructed by Caldwell Tanks, Inc. (Caldwell) of Louisville, KY. Although this sounds like just another construction job, it is not.
Elevated tank construction is a very specialized type of construction with some very challenging safety concerns that, although not uncommon to the construction industry, are more intense and mitigated with techniques less commonly used for other types of construction,” said Kevin Widener, the Lowcountry Resident Office resident engineer. “In addition to the high fall exposure, personnel are more exposed to critical environmental elements, such as wind and lightening, and all the more routine construction project hazards, such as potential of dropped or falling debris, confined workspace, etc.”
This construction site is using an array of preventative measures such as ladder climbing devices, vertical life lines, retractable lines, a safety net, barriers, double lanyards, controlled accesses, restricted work areas, extensive training with safety visibility and more to ensure worker safety.
Caldwell Tanks, Inc. has demonstrated a strong commitment to safety. Their team has readily embraced the Corps Safety and Health Requirements Manual and has worked diligently to adapt and incorporate into their operations any requirements found to be more stringent while willingly explaining and demonstrating the various aspects of their proprietary safety systems.
All employees have received the proper training in fall protection as per the U.S. Army Corps of Engineers” Safety and Health Requirements Manual and from the OSHA construction standard. Rhodes Roberts, quality assurance technician, and Clifford Williams, civil engineering technician, are two District employees that climb this tower on a regular basis and are required to be protected from falls 100 percent of the time. They do this by wearing a personal fall arrest system (PFAS) with a double lanyard when other means of protection are not in place.
Access up the pedestal during construction is achieved via a temporary ladder with a vertical life line and rope grab to which the PFAS is hooked. Once the climber reaches the working platform, they hook their extra lanyard to an anchorage on the platform and then unhook from the rope grab and continue to alternate lanyard hooks until safely above a safety net that is hung immediately below the work platform. Once above the net, personnel are allowed to work without being tied off since a potential fall to the safety net is less than six feet.
However, if the exterior walls have not been raised for the next lift, all personnel are tied off to retractable horizontal life lines that can rotate around the center of the platform allowing movement without having to perform multiple hooking/unhooking. All work on the outside of the pedestal wall is performed by a worker using a chair suspended from a hoist dedicated for this effort while connected to an independent retractable life line. All life lines are designed to support at least 3,000 pounds and the retractable units activate in a manner that will prevent the user from falling more than two feet.
The use of the above processes provides fail-safe fall protection of all personnel ensuring that they cannot fall more than six feet at any time. When working at these heights, one needs to have confidence knowing that if the unthinkable happens, they will be protected.
The District”s goal, for both employees and contractors, is that they go home each and every day to their families without accident. This project is more than halfway complete with work above 140 feet and has incurred no incidences to date.
** Source: Written by Kevin Widner, David Dodds and John Lindsay US Corps of Army Engineers, Volume 3, Issue 3