Graf 320001 Instrucciones Para La Instalacion Y Mantenimiento página 13

6.1 Overground installation
When installing the tank above ground it has to be paid attention to the tank being emptied completely in
case of risk of frost. Furthermore, the tank has to be installed on firm and level ground without sharp
objects. The overall weight of the filled tank (1,650 kg) has to be observed when installing the tank. The
tank should be installed in a shady environment. If the tank is installed in closed rooms, it has to be paid
attention to a floor drain being designed. The tank must not be pressurised, i.e. the overflow installed
(on the side of the tank) has to have the same diameter as the supply. It is imperative to provide sufficient
ventilation.
6.2 Underground installation
6.2.1 Construction site
Under all circumstances, the following points must be clarified prior to installation:
The structural suitability of the ground according to DIN 18196
•
Maximum groundwater levels which occur and drainage capability of the subsoil
•
Types of load which occur, e.g. traffic loads
•
An expert ground report should be requested from the local planning authority to determine the physical
characteristics of the subsoil.
6.2.2 Trench
To ensure that sufficient space is available for working, the base area of the trench must exceed the
dimensions of the tank by 500 mm on each side; the distance from solid constructions must be at least
500 mm.
The embankment must be designed according to DIN 4124. The construction site must be horizontal and
plane and must guarantee sufficient load-bearing capacity.
The depth of the trench must be dimensioned so that the max. earth coverage (see point 2 - Installation
conditions) above the tank is not exceeded. To use the system throughout the entire year, it is necessary
to install the tank and those parts of the system which conduct water in the frost-free area. The frost-free
depth is usually approx. 800 mm; precise information in this regard can be obtained from the responsible
authority.
A layer of compacted, round-grain gravel (grain size 8/16, thickness approx. 150 - 200 mm) is applied as
the foundation.
6.2.3 Ground water and cohesive soils (impervious to water)
Installing the tanks in areas with ground water is admissible, if a sufficiently stable geogrid - to be
provided by the customer - (tensile force at least 50 kN/m² in longitudinal and cross direction) with
dimensions of 2.5 x 2.5 m is installed and anchored above the tank as safety measure against upwelling.
Height of vertical cover in case of ground water and cohesionless soils (permeable to water)
(installation with safety measure against upwelling):
Immersion depth of the tank into
the ground water
Required height above ground
If there is the risk of exceeding the maximum admissible level of ground water, a sufficiently dimensioned
drainage line has to be routed in any case.
In case of cohesive soils (impervious to water), e.g. silt, a minimum height of the vertical cover of
900 mm incl. safety measure against upwelling and a sufficiently dimensioned drainage line are
mandatory.
6. Overground and underground installation
< 650 mm
> 400 mm
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800 mm 1000 mm
500 mm 700 mm
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1200 mm 1600 mm
800 mm 900 mm