Good Engineering Practice for Northern Water and Sewer Systems

All of these pipes performed reasonably well in the areas they were installed. Major problems have
been corrosion of CMP used for sewer mains in Yellowknife (approximately 30-year life span) and
ovalling failure of thin-walled HDPE in older sewer systems.
Currently only seven main types of pipe are in use in the North. See Table 2.1 below.
Table 2.1: Pipe Materials in Use in Canada’s North
Pipe Material
Water
Main
Sanitary
Sewer
Storm
Sewer
Sewer
Service
Water
Service
High Density Polyethylene (HDPE)
Polyvinyl Chloride (PVC)
Cement-Lined Ductile Iron (DI)
Copper
Cement-Lined Welded Steel
Kitec
Corrugated Metal Pipe (CMP)
2.3 ABOVE OR BELOW GRADE INSTALLATION
The trend, since the late 1970s, has been to utilize buried pipes wherever possible. To this end,
only two communities (Inuvik and Norman Wells) construct new above grade systems (utilidors).
Norman Wells does, where possible and practical, utilize buried utilities. Inuvik’s soil conditions
preclude buried pipes, except for isolated areas.
Recommendation
2.3.1 Buried Pipes
Buried pipes are the recommended
alternative, where possible.
Rationale
Buried pipes are not subject to extremes of ambient
temperature, do not disrupt lots and roadways and
are not subject to vandalism. Figure 2.1 is a typical
“trumpet curve” illustrating how temperature
extremes reduce with depth below ground surface.
GOOD ENGINEERING PRACTICE 2-3 Apr-04
Piping