1. Excavate pit allowing for tank dimensions and at least 500mm to each side and 400 to 600mm to the surface. Ensure the base is level and compacted using a 100mm layer of sand. The pit should be benched and/or raked in line with safety regulations.

2. Assemble the modules as per the instructions. There are 4 sides and 3 braces for a standard duty module and 4 sides and 4 braces for an extra-duty module. Any molding defect in the product should be noted and the part set aside for replacement.

3. Place a layer of geotextile fabric on the base and to the sides of the pit with enough overlap to cover the top once complete. The fabric should be overlapped at least 300mm at each seam.

4. Place a layer of the yellow canvaccon liner inside the geotextile on the base and to the sides of the pit, once again allowing enough overlap to cover the top once complete. There should be 300mm overlap at each seam.

5. Begin installation of the tank structure by placing the assembled modules on top and beside one another ensuring the 450mm side is in the upright position.

6. Use AUSDRAIN™ connector pins to create double and triple modules. There are 4 connector pins required to connect one module to another.

7. Install the discharge control pit to one side of the tank. The pit will house the orifice plate and trash screens over the orifice plate and inlet to the tank. The pit should have a lockable/ hinged grate for safety.

8. Connect PVC pipes from the discharge control pit to the tank by using AUSDRAIN™ 150mm pipe connectors or by cutting a hole in the side of the module and inserting the pipe through. The fabric will need to be secured around these connections using adhesive tape.

9. Surround the tank completely with the fabric and liner and overlap where necessary. It is recommended not to leave the fabric or liner exposed to sunlight for extended periods. The liner should be taped at each seam.

10. Back fill the tank with clean sand/ fill to the sides of the tank and to a maximum of 600mm above the tank. There should be no sharp or hard objects in the back fill material.

11. Heavy construction traffic is not permitted over the tank at any time. Small excavators and bob cats on tracks are permitted over the tank once 400mm of cover has been placed over the top.

12. Once installed, section off the tank to prevent any possible construction traffic. If installed under a carpark or driveway, the tank only becomes trafficable for light to medium duty traffic once a re-inforced pavement has been placed over the surface. Extra-duty modules (4 braces) must be installed in trafficable areas.