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5.
Installation and assembly
5.2.4 Connection of several tanks
Two or more tanks are connected via the assembly surfac-
es by means of GRAF special seals DN 100 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 100 mm - 150 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 with
approx. 25 cm water before filling the tank surround.
Afterwards the surrounding (roundgrain gravel, max. grain
size 8/16) is then filled in layers of max. 40 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, subse-
quent 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 sew-
er) according to DIN 1986.
All suction, pressure and control lines must be routed in
an empty pipe, which must be routed as straight as pos-
sible, without bending, to the tank with a decline. Neces-
sary bends must be formed using 30° moulded sections.
Important:
The empty pipe must be connected to an
aperture
above
the max. water level.
Sewe
