Line Acceptance Testing: Both ends of the pipe are blocked off at manholes with inflatable balls – one just plugged and the other with a test unit attached. Low pressure air is introduced into the sealed pipeline thru one of the balls. A gauge is used to accurately measure the acceptable pressure needed in the line.
Leak location is actually a series of small line acceptance tests. Two inflatable balls are connected and pulled through the pipe 25 feet at a time to find a leak. An air test is run each time the balls are stopped. When a section fails, the contractor is notified so that they can either check the services at the point of failure or dig up the line to find where the leak is occurring.