Prelocation block

The planning of infiltration ditches/tanks

The Graf Rain Bloc is a system which has been particularly designed for the rainwater infiltration and retention respectively.
The structure of the modules enables a space-saving installation with minimal earth covering. The surface beyond the Rain Bloc can even be used by traffic. An exact calculation according to ATV-DVWK-A 138 or corresponding, country-specific technical regulations in force must be followed. In order to avoid silt accumulation the system must be equipped with an infiltration filter.
The installation has to be done in a professional
manner.

Choice of position
The distance of the ditch to adjacent buildings with non-sealed up cellars has to be at least 6 metres. For maximum infiltration performance the Graf Rain Bloc requires a distance of at least 1 metre to the ground water.
The distance to existing or planned tree population must correspond at least to the (expected) diameter of the crown.

Installation of the feed and ventilation pipes
The feed and ventilation pipes will be connected laterally at the designated position. For this purpose, the plastic ribs must be detached. The pipes must extend into the modules approximately 200 mm. For extensive laying of the modules it is essential to distribute several feeding pipes in a homogenous way so that the water can flow in steadily.

Installation of the Rain Bloc
The impermeable membrane is put on the horizontal, flat footprint of the excavation with 500 mm overlapping. The modules are positioned horizontally on the membrane and connected with each other by plastic connectors. For lengthwise and crosswise connection each 4 connectors are necessary. For systems with various layers, the different layers must show an alternate arrangement of lengthwise and crosswise layers to obtain maximum stability. Before the excavation is filled with material, all the modules must be wrapped completely with fleece, whereas the ends of each fleece line must have an overlap of at least 500 mm. After that the excavation is filled in layers and constantly compressed.