Norco Manufacturing Co., Inc.
The Cylindrical Stopper for Water Mains
In water work, the practice is to place the Stopper in the open end of the pipe after the cutout is made wherever a leaky valve is encountered. This permits the work to be carried out on dry ground. The only wet joints would be on the sleeve at the closing-in point.
If leaky valves are encountered, a Cylindrical Stopper will hold back all leakage. It will hold back enough pressure to furnish water to the second floor of houses on the line shut down, or leakage may be wasted through a hydrant on the line.
Men work more quickly and do a better job when working on dry ground.
On jobs where there is no branch fitting as shown above, the Stopper will have to be withdrawn before the sleeve is in place.
USE A PRESSURE GAUGE
Cylindrical Stoppers should not be inflated over the pressures shown on the tag fastened to each Stopper. These pressures leave a margin of safety. They are about half the breaking point under test in the shop.
Use a gauge and watch it. It prevents over inflation and shows that the Stopper is holding.