Cleaning

An action of a boring machine to remove spoil that occurs when the auger is rotating while axially stationary.

Close-fit

Description of a lining system in which the new pipe makes close contact with the defective pipe at normal or minimum diameter. An annulus may occur in sections where the diameter of the defective pipe is in excess of this.

Closed Face

Term referring to one mode of operation of a traditional tunnel boring machine (TBM).

Closed-Circuit Television Inspection (CCTV)

Inspection method utilizing a closed circuit television camera system with appropriate transport and lighting mechanisms to view the interior surface of sewer pipes and structures.

Clutch

A mechanical device that engages or disengages rotary torque from a power source.