3.0 INSTALLATION
© Presby Environmental, Inc., Design & Installation Manual, July 2020 Edition
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Inspection Port (optional)
When an inspection port is desired or mandated by regulators, the cutout in the center of the cover is used. The
cutout will accommodate 4-in Sch. 20 to 40 pipe. The inspection port is constructed from third party plastic pipes
and fittings. The inspection port is to be constructed with watertight fittings and joints. The top of the port should
be within a few inches of the final grade. The inspection port may also extend above the final grade. Apply silicon
caulking (or equal) to the inspection port and cover’s mating surfaces.
Illustration of typical inspection port:
Backfilling EnviroFin Unit(s)
1.
Place and secure cover on FDU with stainless steel screws provided.
2.
Attach inspection port if required. Apply silicon caulking to mating surfaces.
3.
Carefully place system sand around treatment fins, FDU’s, upper connection and EQ Connection pipe.
Lightly tamp to fill voids.
4.
Ready for state and/or local inspection if required.
5.
Optional - Place magnetic tape or ferrous metal (rebar, etc.) over top of FDU(s) so they can be located
easily using a metal detector.
6.
Continue placing system sand to a minimum of 3 in over the treatment fins and a minimum of 6 in beyond
the perimeter of the outermost treatment fins.
7.
Once required amount of system sand is achieved, place topsoil (material free of organics, stones over 4
in and building debris, having a texture similar to the soil at the site), without causing compaction.
8.
Grade field to shed water.
Backfilling and Final Grading
1.
Spread a minimum of 4 in of suitable earth cover (topsoil or loam) free of organics, stones over 4 in and
building debris, having a texture similar to the soil at the site, without causing compaction.
2.
To prevent erosion, soil cover above the system shall be planted with native, shallow-rooted vegetation
such as grass, wildflowers and certain perennials or ground covers. No trees or shrubs should be located
within 10 ft of the system perimeter to prevent roots from growing into and damaging the system.
Fill Extensions Requirements
All systems with any portion of the system sand bed above original grade require 3 ft fill extensions on each side
beyond the outside edge of all EF treatment fins and then tapering to meet existing grade at a maximum slope of
3:1. There must be a minimum of 12 in of cover material over the ends of all system sand extensions (if present).