Precast Base Unit
The prefabricated base unit provides the foundation, channelling, benching and starter ring all in one complete unit. It also includes a rubber ring coupling at each outlet. There are many advantages in using a prefabricated base:
- Structural – High strength, factory made concrete for the foundation where loads often exceed 200 KN.
- Chemical – Only “Dolomitic Aggregate” is used, thus ensuring a prolonged life against the aggressive environment in the manhole.
- Water Tightness – The factory made concrete guarantees water tightness and provides a flexible joint at the point where the pipes are subjected to the greatest movement. Less joints to leak.
- Time – No standing around waiting for the concrete to cure- No battling to pour good concrete in the mud and – No waiting for the next certifcation because the manholes are not complete. Lay approximately 4 per hour.
- Effort- Construction is simple, There is constant height from “Level of invert” at centre of manhole to underside of foundation – so excavate to this level. The required fall is already built into the slope of the channel – drop the base unit into position and start laying pipe.
- Adaptability – Joints available for P.V.C Pipes.
- Hydraulics – The built-in gradient on each junction allows for the head loss that occurs in each case.