Drawing Ref: T670
The following shall apply:
- Only PE80 or PE100 pipes conforming to AS/NZS 4130 shall be used for rising mains. The required minimum pressure rating for a rising main shall be PN 10. Higher rated pipes may be necessary. Other materials may be considered by Council.
- Pipe selection shall take into account a 100 year service life and include derating due to operating temperature and derating due to 107 cycles of cyclic water hammer load causing pressure swings from 1.5P to 0.5P.
- A safety factor of not less than 1.25 shall also be included to determine the pipe pressure class.
- PE fittings fabricated from pipes shall be derated due to stress concentrations in the fabricated fittings. Manufacturer's recommendations shall be strictly followed with regard to the extent of derating required for each type of fabricated fitting.
- Wherever possible, the rising main shall be designed on a positive gradient avoiding high and low points, therefore minimising the need for air release and scour valves.
- PE pipes shall not be used for pipe bridges or within tunnels that are not backfilled unless the pipe is adequately anchored against flotation and thermal movement.
- To accommodate all out of balance forces on the main its installation and design shall be similar to that of a water main incorporating suitable anchorage at all changes of direction.
- Rising mains shall be installed with "sewer" marker tape laid continuously 200mm above the rising main. The tape shall include a metallic wire that can be detected from the surface.
- Where any section of a rising main is installed by trenchless technology, tracer wire shall be strapped to the pipe and fixed thereto by using a minimum of 2 complete wraps of 50mm wide heavy duty adhesive tape at a maximum of 3.0m intervals. Wire traces shall be continuous to allow an electrical current. Rising mains shall discharge into a receiving manhole in accordance with the detail on the Standard Drawings.
- Rising mains shall be a minimum of 76mm ID.
Definitions in this section