1. During installation of GRC components, appropriate safety wear is recommended e.g. gloves, protective glasses, etc.
2. Prior to installing the pit, determine and set-out the exact position of the inlet and outlet services on the external surface of the GRC pit walls. Take care to ensure the pit is installed in accordance with the design levels and details provided on the project drawings.
3. Mark the outline of the penetration on the outside of the wall of the GRC pit.
4. Penetrations can be formed by using a ball peen hammer. Using the ball peen end of the hammer, locate the centre of the penetration and start tapping until the material disintegrates and a small hole is made. Keep “tapping” around the hole until it opens up to match the outline of the penetration.
5. Neatly excavate the foundation material to suit the external dimensions of the GRC pit and risers ensure the excavation is slightly deeper to allow for a granular backfill zone plus a cement mortar bedding layer under the pit base. The depth of the granular backfill zone will depend on the quality of the foundation material.
NOTE: It is essential that the base of the pit is founded on competent material with adequate bearing strength to prevent settlement or deflection of the pit during service.
6. Immediately after placing the granular backfill followed by the 50mm bedding layer comprising of a sand/cement mortar mix, lower the pit into position ensuring the correct alignment of the service penetrations.
7. Complete all service connections to the pit in accordance with the project design drawings. Ensure services are secured and the penetrations patched using an approved epoxy mortar to provide a water tight joint.
8. Backfill around all sides of the pit, using the sand/cement mortar mix, to a level of 200mm above the pit base.
9. Fit the extension risers and seal the riser joints using an approved epoxy mortar.
10. Backfill around all sides of the pit and risers up to ground level using compacted granular material.
NOTE: ensure appropriate compaction equipment and effort is used to prevent damage to the GRC components.
11. Install the BCP grate or cover onto the completed pit installation.
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