Crew

The number of persons required for the performance of work at a site as determined by the contractor in response to task difficulty and safety considerations at the time or location of the work.

Critical Sewers

Sewers with the most significant consequences in the event of structural failure.

Cross members

The lateral supports under the track of a boring machine.

Crossing

Pipeline installation in which the primary purpose is to provide one or more passages beneath a waterway, road, or other surface obstruction.

Crown

The highest point of the pipe or tunnel.