Southern Nevada Water Authority
The Southern Nevada Water Authority wanted to expand the capacity of the Las Vegas area potable water delivery system. The area had experienced phenomenal residential and commercial growth, placing ever-increasing demands on the water system. The strategy for accomplishing the basic expansion included the addition of one new 180" line tied into the existing 120" water main running from Lake Mead. A second water treatment plant was also to be built.
TDW Services, Inc., was selected to perform two record-breaking, 102" taps in the 120" I.D. / 142" OD, steel reinforced concrete pipe with 11" wall thickness. This represented another first for TDW! It was a monumental task... one that had never been accomplished before.
The two 102" taps were performed routinely, using a TDW Model 2400 Tapping Machine, with each tap completed within a 16-hour period. The two huge, 8,000 pound coupons were retained by the tapping machine and retrieved through the 102" holes.
Baltimore Waste Water
TDW plugged a 96" wastewater line, composed of pre-stressed concrete pressure pipe with a steel cylinder, for the city of Baltimore, MD. This record-breaking project involved tying in their 96" Southwest Diversion wastewater main into a new Grit Removal Facility at the Patapsco Wastewater Treatment Plant. The plant received an average daily flow of 70 MGD, at operating pressures between 10 and 14 psi. Shutting down the main while making the new connections was simply not feasible.
After successfully completing the 60" taps, TDW Services installed two 60" x 96" folding head STOPPLE® Plugging Machines. The plugging heads, in their folded positions, were retracted into the housings and lowered down through the tapped holes into the pipe. As the guide wheels came into contact with the bottom of the pipe, the plugging heads opened...and the elastomer sealing elements, assisted by differential pressures, created positive seals against the walls of the pipe.
This highly effective line stopping system was used to isolate a 200-foot section of the 96" wastewater line. A temporary 60" bypass was installed to maintain flow while the main was being tied into the new Grit Removal Facility. The Project Manager complimented TDW Services by saying, "We knew of their good reputation, and they deserved it on this job."
