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10.3.1 Excavation size:
Suitably sized equipment will be required to excavate the hole and to lift the system into
place.
Installation depends on on-site conditions, water, slopes, location etc. Excavation should be planned
with due regard to health and safety requirements. The excavation should allow a minimum 250mm
clearance between the tank and the excavation wall or face of shoring. A minimum of 500mm is
also required between adjacent tanks. Unstable ground with excessive sand, peat swamps etc. may
require larger excavations. The excavation should be maintained dry by pumping or whatever suitable
means.
Total excavation: {Width. + 500mm} x {
500mm} Excavation depth:
Dry Site: Allow 250mm for tank
base/plinth. Wet Site: Allow 300mm for
tank base/plinth
Please note max manhole riser is 750mm
Tank Size
Excavation
Size
Tank A (m)
6 person
2.1 x 2.15
8 person
2.1 x 2.15
10 person
2.6 x 2.15
12 person
3.1 x 2.15
18 person
3.6 x 2.15
24 person
4.1 x 2.15
30 person
5.1 x 2.15
36 person
6.1 x 2.15
42 person
6.1 x 2.15
50 person
7.1 x 2.15