GRAF 1500Lt Li-Lo Underground Tank
Do you want to harvest rain water without valuable surface space being taken up by a tank? Graf’s underground water tanks are made in Australia according to a patented and leading German-engineered design that provides optimum strength and a self-cleaning filter.
They are your perfect solution and so easy to install that two friends, two shovels and one morning is all that is necessary. No ballasting is necessary for the foundation and tanks come with child proof covers.
Li-Lo Underground Tank Features
- German engineered and manufactured in Australia.
- No Ballasting required.
- Compact shallow excavation design.
- Fully integrated self cleaning option.
- Driveway manhole option available.
- Child-proof cover option available.
- 75% Less Digging than a Concrete Cistern
- Save more than 100 wheelbarrow loads of soil
Pedestrian Weight Resistant
The GARANTIA Li-Lo Rainwater Underground Tank with the PE cover may only be installed in traffic free areas. The amount of short-term load of the PE cover is a maximum of 150 kg. The long-term area load max is 50 kg.
Figure 1. Approved earth coverage height with Garantia PE-lid in green areas.
Figure 2. Maximum allowed earth coverage height with second Garantia extension riser as adaptor or extension and PE Lid. Greens areas only. Not to be used by passenger cars.
Light Traffic Load Resistant
The GARANTIA Li-Lo Rainwater Underground Tank with the cast iron cover (Class B) are suitable for installation in light traffic areas (max. total load 3.5 ton). The tanks are not to be installed in areas where heavy goods vehicles are driven (Class C or D).
The areas driven by light traffic must have a compacted earth covering of not less than 700 mm (27.6 inch) and a maximum of 1000 mm (39.4 inch). Under no circumstances is the load caused by vehicles to be transferred to the tank.
Figure 3. Allowed earth coverage height with Garantia extension riser and car module with cast iron (Class B) in areas used by passenger cars. Max total load 3.5 ton without ground water and stratum water)
Figure 4. Please note 7500LT not availale in Australia at the present time. Htot does not include lid.
Extension Riser for Graf LiLo Underground Tanks
Figure 5. Extension Riser minimum heights and max effective height.
Garantia Li-Lo Underground PE Lid
Figure 6. Height and diameter of PE lid.
Garantia LiLo Class B Lid
Figure 7. Height and diameter of Class B Lid
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.
To ensure that sufficient space is available for working, the base area of the trench must exceed the dimensions of the tank by > 100 mm (3.9 inch) on each side; the distance from solid constructions (e.g. foundations of the house) must be at least 1000 mm (39.4 inch).
If the depth of the trench is > 1250 mm (49.2 inch) an 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 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. 600 – 800 mm (23.6 – 31.5 inch); 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. 100 – 150 mm; 3.9 – 5.9 inch) is applied as the foundation
If the underground tanks are installed adjacent to surfaces which are used by heavy vehicles weighing over 3.5 ton, the minimum distance away from these surfaces is at least the depth of the trench.
Two or more tanks are connected via the assembly surfaces by means of GARANTIA special seals and basic pipes (to be provided at construction site). The apertures must be drilled to the corresponding size using only the GARANTIA special crown bit. It must be ensured that the distance between the tanks is at least 500 mm
(19.7 inch). The pipes must project at least 200 mm (7.9 inch) into the tanks.
The tanks must be inserted, impact-free, into the prepared trench using suitable equipment. To avoid deformities, the tank is filled 1/3 with water before back filling the excavation. Afterwards the surrounding (round grain gravel, max. grain size 8/16) is then filled in layers of max. 30 cm (11.8 inch) and is compacted.
The individual layers as well as the medial support column must be well compacted (manual tamper). Damage to the tank must be avoided during compaction. Mechanical compaction machines must not be used under any circumstances. The surrounding towards the trench must be at least 100 mm (3.9 inch) wide i.e. the distance between each wall an the tank must be ≥ 100 mm (3.9 inch).
Diagram of Detention System setup for Graf LiLo
Diagram of Multiple Tank Installation with Onsite Retention and Detention