www.graf.info
16
/
36
5.
5.2.4 Connection of several tanks
Two or more tanks are connected via the assembly
surfaces by means of GRAF special seals and basic pipes
(to be provided at construction site).
The apertures must be drilled to the corresponding size
using only the GRAF special crown bit. It must be ensured
that the distance between the tanks is at least 600 mm.
The pipes must project at least 200 mm into the tanks.
5.3
Insertion and filling
The tank must be inserted, impact-free, into the prepared
trench using suitable equipment. The tank is filled to 1/3
with water before filling the tank surround.
Afterwards the surrounding (roundgrain gravel, max.
grain size 8/16) is then filled in layers of max. 30 cm
steps and is compacted.
The individual layers must be well-compacted (manuel
tamper). Damage to the tank must be avoided during
compaction. Mechanical compaction machines must not
be used under any circumstances. The surrounding must
be at least 500 mm wide.
5.4
Routing connections
All feed and overflow pipes must be routed with a
decline of at least 1% in the direction of flow (possible,
subsequent settling must be taken into consideration in
this case). If the tank overflow is connected to a public
sewer, this must be protected against reflux by means of
a lifting station (mixed sewer) or reflux seal (pure
rainwater sewer) according to DIN 1986.
All suction, pressure and control lines must be routed in
an empty pipe, which must be routed as straight as
possible, without bending, to the tank with a decline.
Necessary bends must be formed using 30° moulded
sections.
Important:
The empty pipe must be connected to an
aperture
above
the max. water level.
Sewer
