This document is the Lining of Casings with SaniTite HP Pipe. Casing pipe size, structural requirements, casing spacers/skids and installation explained.

In sanitary sewer, it is necessary to use trenchless technology methods to install a casing pipe under high volume roads or railroads where the ground surface cannot be disturbed. Methods of installing the casing pipe will vary based on the native soil conditions, groundwater location, length of installation and the precision required for the pipe line and grade. SaniTite HP pipe can be used as a carrier pipe within a casing, provided open pits that are used at each end of the tunnel operation to prevent bending of the pipe in place.

In sizing of the casing pipe, the diameter of the casing pipe may be limited by the in-situ conditions, such as proximity to bedrock or the presence of weak native soils. Where in-situ conditions are not the limiting factor in casing sizing, the smallest possible diameter pipe is often desired. Table of dimensions of HP Products provided.

In the case of trenchless casing pipe installations, the casing pipe being installed is typically designed such that the live and dead loads are carried solely by the casing pipe with no load being transferred to the carrier pipe.

Installation Techniques for the length of sewer section requiring a casing is less than 300ft when road or rail crossings are relatively narrow. For these circumstances, a typical method involves joining successive carrier pipe joints together outside of the casing while pushing the carrier pipe through the casing. A second method involves passing a cable through the casing and the first stick of pipe to pull the pipe in place. Figure of Pulling HP Pipe in Casing and Table for Maximum Push Force on HP Products and Alternative Installation Method shown.

Casing Spacers and Skids recommends that skids may be attached to the carrier pipe to provide a sliding surface between the casing and the carrier pipe. A chart, Unsupported Deflection of SaniTite HP is provided.

Closure After Pipe Installation is discussed with supporting photographs.