Television Inspection (TVI)
TVI stands for televised video inspection. A TVI allows us to get “eyes” inside the pipe by inserting a closed-circuit camera. TVIs are a very important part of our maintenance process, as they allow us to quickly assess a pipe’s condition and identify what may be obstructing flow or causing problems for customers.
When are TVIs done?
During regularly scheduled maintenance of both lateral and main line pipes, SASD field crews typically use TVIs to assess pipe condition and determine if the pipe needs any immediate cleaning or repair. If cleaning is needed, a TVI is repeated to ensure the pipe is free of debris. TVIs are also done after any construction work to ensure that the work was done correctly.
How are TVIs done?
For our smaller lateral pipes—which connect our main line sewers to customers’ homes or businesses—a small TVI system is used. The crew member inserts the camera into the pipe through an SASD cleanout. For our larger main line pipes, a much larger camera is used. In those cases, the TVI camera is attached to a guide line and pulled through the pipe while an operator inside a special TVI truck views the images on a video screen and carefully documents any visible issues about the condition of the main line.
What does SASD do with TVI footage?
Notes on the pipe’s condition and any observed issues from TVIs are recorded and kept in our database system. In most instances, a secondary review of TVI footage is completed by our in-office TVI technicians, who look for problems that might have been missed in the field. Our office technicians make maintenance and repair decisions based on all available SASD inspection history. This lets us see what is occurring with the pipe over time so we can determine if any repair or ongoing maintenance action on that particular pipe is necessary.
What are the impacts to customers?
Of all the field work we do, TVI work has the least impact—and often no impact—to a customer’s property, as it involves only the insertion of a camera into the pipe through a cleanout or manhole.