Pit Placement
Pits are to be placed to the relevant levels particular to the project. All necessary preparation, care and measurements should be taken before placement. Prior to construction of pits, an engineer or local government authority should be consulted for maximum allowable pit depth.
Unloading
Small diameter pits (up to 450mm diameter) and lids may be unloaded and placed by hand. It is recommended that larger diameter pits (600mm and 750mm diameter) and lids should be handled with machinery for lifting and placing. Care should be taken during unloading and handling to protect the rebated end/s of the pit starter and body. Lifting holes are provided, and pits should only be lifted from this point with the approved pins
Installation Details
Refer to our Working Safe information before installation.
Cutting
To alter the height or add an inlet/outlet to a pit system.
It is recommended that a power saw, fitted with an appropriate abrasive disc or diamond blade, be used for cutting of FRC™ pits. Refer to our Working Safe information.
Inlet/outlet pipe: - shaping a profile.
a) Scribe the outline on the pit starter according to the diameter of the inlet pipe.
b) Cut vertical strips in the pit starter up to the scribed line.
c) Break off and remove the cut sections.
d) Trim profile edge with a coarse rasp to suitable finish.
Pit Body: - Adjusting the pit body to suit your required height.
a) Scribe the pit body to your required height (allow for the depth of the lid or grate in accordance with requirements of finishing flush with the ground surface).
The height of a standard pit system is 1200mm (nominal) - this includes a pit starter and pit body. Should you need to increase the height required, this can be achieved by adding an inverted pit starter above the pit body.
b) Cut pit body according to your scribe.
c) Trim pit body with a coarse rasp to a suitable finish.
Bedding
Bedding should comply with the general standard set down by the local authority or its appointed officer. Special consideration should be given to particular situations. General acceptance is to approved bedding material compacted to a thickness of not less than 80mm on an earth foundation, or 150mm on a rock foundation. The invert of the pipe, pipe wall thickness, and base thickness, are to be taken into account when levelling bedding material for pit placement.
Pit System Assembly
a) Pour suitable concrete footing in preparation for placing the pit starter.
b) Place the profiled pit starter over the stormwater main.
c) Bench concrete around the outside of the pit starter to a height of 150mm (nominal) above the stormwater main to secure a sound footing for the pit system.
d) Place concrete benching inside the pit at 10 degrees slope to outlet in stormwater main.
Pipe Installation
Pipe installation into pits requires the pipe to be finished flush with the internal wall of the pit, with an approved cement mortar mix used to grout the pipe into the pit. The works supervisor may specify special grouting in harsh environments. Wall penetrations are designed to allow easy placement of pipes into the wall. Refer to our Working Safe information.
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