6-6 OTHER INSTALLATION CONSIDERATIONS

Joining different Pipe Types or sizes

Drainage systems often involve connecting pipe of different materials or sizes. Options to make these transitions are often limited by the joint quality required. One very common method of connecting different types of pipe of the same size, and in some cases different sizes, is through the use of a concrete collar. This generally provides a minimum silt-tight joint quality but ultimately depends on workmanship. A concrete collar is formed by butting the two pipe ends together, wrapping the junction with a geotextile to keep out most soil and concrete, and then pouring a concrete collar that covers both pipe ends.

Another option may be using fittings or adapters specifically designed for this application. Hancor offers a selection of fittings designed to make the transition from one material directly to another. In other cases a Hancor fitting may need to be used in combination with another manufacturer’s gasket, for example, to complete the transition. Transitions made in this manner may be more watertight than a concrete collar.

Manholes or catch basins can also be used at changes in pipe materials or sizes, and are required by many agencies. Manholes can be more costly than other alternatives but can also allow grade and directional changes in addition to changes in pipe material and size. Local regulations should be consulted to determine if manholes or catch basins are required at any or all pipe changes.