Obstruction

Any buried object that lies completely or partially within the cross section of the microtunnel and that impedes continued forward progress along the design path and within allowable tolerances.

Ogee

A joint with an elongated “S” profile within the thickness of a sewer pipe wall.

Oiler

Changes amount of lubricating oil injected in supply air.

One-Pass

A procedure by which the carrier pipe is directly jacked into the ground.

OPC

Ordinary Portland Cement; customarily used for making concrete, mortar and grout in non-aggressive conditions.