The Cylindrical Stopper for Gas and Water Mains
Waiting on Descrip
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.