Impact Strength

The ability of a material to withstand shock loading.

Impervious

Impenetrable. Completely resisting entrance of liquids.

In situ

Describes work on site; in the original place. For example, in situ concrete would differentiate cast in place concrete from precast concrete.

In-line Microtunneling

A method of replacing an existing pipe by filling the pipe with flowable fill to prevent fluid loss and then excavating the entire pipe and surrounding ground with an MTBM for a new installation.

In-Line/On-Line Replacement

The breaking out of an existing pipeline and the installation of a new service on the same line. See ReplacementConstruction of a new sewer, on or off the line of an existing sewer. The function of the new sewer will incorporate that of the old, but may also include other improvements or development work..