4rain FLAT S Notice D'installation Et D'entretien page 47

5.5 Transferring the tank to the pit and backfilling
Suitable equipment should be used to move the tanks gently into the prepared pit. Deformations are elim-
inated when the tanks are filled to a third of their depth with water and checked for leaks before the pit is
filled.
The underground tank must be surrounded with a suitable filling material. Unsuitable or inadequately pro-
cessed filling material might cause damage to the tank and form cavities.
The filling material must:
•
be free of sharp or pointed parts and objects
•
be well and uniformly permeable to water
•
be easily compactable and form a tight packing around the underground tank
We recommend as the filling material round gravel with a max grain size of 8/16 mm. Round gravel need
not be compacted.
Lay the surround in successive depths no greater
than 300 mm until it reaches the tank's top edge.
Compact each layer carefully using a hand tamper.
Mechanical compacting machines must not be
used under any circumstance. Observe the mini-
mum width of the side surround as set down in
Tab. 8.
Important: Make sure that the filling material fully
surrounds the tanks and that it can be compacted
easily at the connecting points and inter-tank cavi-
ties. Use chips for FLAT tank (max grain size
2/5 mm)!
Fig. 30: Insertion and filling – FLAT
Fig. 32: Insertion and filling – MODULARIS
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5 Installation and assembly
Tank
FLAT S/M/L/XL
MODULARIS
COMPACT
PROFI
Tab. 8: Minimum side filling width – FLAT,
Fig. 31: Inter-tank cavities – FLAT
Fig. 33: Insertion and filling – COMPACT, PROFI
47 / 108
Minimum surround width
MODULARIS, COMPACT, PROFI
100 mm
500 mm
500 mm
500 mm