Follow these 7 tips to ensure a top-quality backfill job as part of your UPP® pipework systems installation:
- A recommended 15cm (6″) bed of backfill material should be laid underneath the pipe prior to installation and there must never be voids under or around the pipe or contamination in the backfill.
- Use acceptable backfill materials including:
- Well-rounded pea gravel size 3 mm (1/8″) to 20 mm (3/4″).
- Crushed rock size 3 mm (1/8″) to 16 mm (5/8″).
- Clean washed sand.
- Particular care should be taken to ensure enough backfill is laid down around the underside of the chamber should it overhang the tank containment collar.
- IMPORTANT: Backfill material should fully support UPP® pipework and be free from ice, organic silt, or peat which could disappear over time causing voids or possible ground movement. No mechanical compactors should be used such as vibrating plates, compactors, or road rollers.
- UPP® pipe exceeding 12m (39ft) should be laid in a series of large snake-like curves and not in straight lines. Uncoiled pipe, when laid, will settle in a natural curve.
- Pipes should be separated from each other by at least the diameter of the largest pipe.
- If pipe-runs cross each other they must be separated by at least as much backfill material as the diameter of the largest pipe or protected using at least 25mm (1”) of expanded polystyrene.
The Effects of a Bad Backfill Job
In the image to the left, professional contractors carefully followed all of the guidelines to ensure a high quality UPP® pipework system installation. However, when the time came to add backfill beneath the tank chambers the contractor was less careful. The careless backfilling knocked the pipe out of position, dislodged spacers and contaminated open entry seals and other fittings with backfill material.
The backfill material must now be removed from sumps, chambers and open fittings and the pipework levels must be reset, will all spacers replaced. This will take a considerable amount of time and delay the installation, with all the associated financial costs that implies. It is important that all parties involved in an installation understand the care and attention to detail that go into a smooth and problem-free installations. A simple but careless mistake can have big implications for the installation.
Technical Bulletin: Backfill Requirements and Specifications: http://www.franklinfueling.com/media/671398/tb0616-03-backfill-requirements-and-specifications.pdf
UPP® Piping Installation Guide Overview, Franklin Fueling Systems http://www.franklinfueling.com/media/381133/408001016-r5-upp-piping-install.pdf
Polyethylene Tank Chamber / Sump Installation, Franklin Fueling Systems http://www.franklinfueling.com/media/344841/408001028-r3-upp-tank-sump-install.pdf