Graf easyCompact Serie Gebrauchsanleitung Seite 46

4 Installation and assembly
4.2.4 Bedding and backfilling – materials and execution
The bedding and backfilling of the system depend on the soil and water conditions at the installation site.
The system may be installed using only bedding and backfill materials suitable for the installation situation.
Unsuitable or improperly installed bedding and backfill materials may cause damage to the system or
cause it to float, and cavities may form.
Installation situation
Dry soil
Damp soil
Tab. 8: Materials and layer thicknesses of the bedding and backfill for dry and damp soil
Excavated soil can be used for the top 20 cm of the covering layer if it meets the following requirements.
The excavated soil must:
• Be free of sharp or pointed parts and objects
• Be well and evenly permeable to water
• Be well compactable
Cohesive soils (silt, clay, etc.) must not be used for the covering layer.
4.2.5 Permissible cover heights
To ensure the stability and breakage resistance of the system, the cover height above the tank shoulder of
the primary sedimentation tank must be between 25 cm and 96 cm.
For cover heights of < 45 cm, shorten the shafts as described below.
Using an extension set, 2
(not shortened) may be installed. The maximum cover height of 96 cm must not be exceeded.
1 See also Section 4.2.7.1
Optional accessory (see also Part 1 of the instructions)
2
46
Bedding
Material
Rounded gravel,
grain 8/16 mm
Reinforced concrete
slab 1
the cover height can be increased by up to 41 cm. A maximum of 1 extension set
Instructions Wastewater treatment system easyCompact
Height Material
Rounded gravel,
10–30 cm
grain 8/16 mm
Stabilised sand 0/4,
≥ 20 cm
200 kg cement/m³
Filling
Backfill area
≥ 50 cm at the side
of the system
≥ 20 cm on top of
primary sedimenta-
tion tank
≥ 40 cm at the side
of access shafts
963325