|This project was completed for a primary school in Cork City. A drain downstream of a drop manhole was continually blocking up due to the condition of the drain from the boundary to the public sewer on the road. An internal free-drop (drain entering an access point above the invert level and dropping freely onto the benching and channel) installed some time in the past did not help the matter either.
However, the public road was a narrow one way street and traditional dig down and replace methods would be very costly. The good news was that the CCTV survey showed that the drain did not possess any service or structural defects that would warrant such a measure and drain re-lining would be the most reasonable approach to rehabilitation.
The basic principle in relining is to introduce a tough polyester tube into the old drain. The liner is impregnated with resins and then dragged into the damaged line. The liner is then inflated under pressure by a specialist calibration hose and is kept under pressure until the resins have cured ensuring maximum contact with the original pipework and the liner has become solid. The calibration hose is then removed and the pipe has been sealed, reinforced and smoothed out to leave a water tight pipe.
Substruck Ltd. re-lined the drain, installed a new internal drop system and re-benched the manhole. The drain / manhole was monitored for a period of over one year and was found to be performing perfectly.