6.2.3 Installation next to driven-on surfaces
If installing the tank next to surfaces which are
driven over, ensure that the loads produced by
heavy vehicles are not transferred to the tank. The
tank must be at least 1200 mm away from driven-
on surfaces.
6.2.4 Connecting multiple tanks
Two or more tanks are connected via the mounting
faces moulded into the lower part of the tanks
using special GRAF seals and underground pipes.
The openings must only be drilled with the GRAF
special core drill and to the appropriate size.
Ensure that the distance between the tanks is at
least 800 mm. The pipes must extend at least
200 mm into the tanks.
6.3
Insertion and filling
The tanks should be brought into the prepared
trench with a suitable device without any jolts (also
refer to 5 – Transport and storage).
To avoid deformation, the tank is 1/3 filled with
water before the tank surround is filled in. The
surround is then 1/3 filled in with layers of max.
300 mm (round gravel, max. grain 8/16 in
accordance with DIN 4226-1) and compacted. You
should then fill the tank until it is 2/3 full and fill the
trench with layers of max. 300 mm until it is 2/3
full, etc.
6.3.1 Fill material
The fill material must be easily compacted, permeable and frost-resistant, must not slide and
•
must be free of sharp objects.
For example, round gravel (the grain should not exceed 8/16 in accordance with DIN 4226-1)
•
displays these properties.
Excavated soil or sand is not usually suitable.
•
Top soil, clays and other cohesive soils are not suitable for use as filler.
•
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6.
Installation and assembly
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> 800
>800