Definition - What does Line Belly mean?
A line belly can be defined as a sag in a sewer or water pipe, usually near a joint in solid pipes such as those made of cast iron.
Most sewer lines work on the concept of gravity and when a line belly is formed in a pipe, it can disrupt the normal flow of water causing sewage backup and pooling at the site. Line belly is often diagnosed as the culprit when channeling is the actual problem. Unlike a line belly, channeling can be fixed through trenchless methods.
The only way to remedy a line belly is to excavate using conventional trenching methods, remove and completely replace the pipe after providing adequate slope and proper bedding. Trenchless video inspection methods can be used to determine if a line belly has occurred in the pipe.
Trenchlesspedia explains Line Belly
The primary cause of a line belly occurring in sewer pipes is improper bedding during pipe installation. However; it can also be caused by other factors such as foundation settlement or geological disturbances such as earthquakes and erosion. The positive slope of a gravity sewer becomes negative beyond the portion where the line belly has occurred. This results in accumulation of water during low flow hours and gradual collection of debris in the sagging area. This accumulation can lead to complete blockage of the pipe.
Trenchless methods of sewer inspection can be carried out using video cameras mounted on crawlers or push rods which are inserted into the affected pipe. An experienced plumber can easily diagnose the problem using images and video footage from the inspection and save unnecessary cost associated with wrong diagnosis.