Accepted construction standards and specification should be followed where
applicable. The sequence of
construction for a tree box filter is provided below. This is an example of
a proprietary version of a tree box filter system known as Filterra™, which
is sold by Americast Inc.1
Please contact
Americast Inc. to get further information on the availability of this
system and to avoid possible patent infringements (Patent#
6,277,274).
The
Filterra™
system can be installed at any convenient time during the construction
of the site. However, the device is best installed after the
installation of the site's infrastructure as a drop in place device.
The Filterra™ system
should not be placed in service until the contributing drainage area has
been stabilized. If the device is installed during construction of the site’s
infrastructure, the inlet must be protected from sediment. Follow the
manufacturer’s recommendations on sediment / erosion protection. The
specification for the construction of tree box filters should state the following:
1) the earliest point at which the runoff can be directed to tree box filter devices and 2) the means by which this delay in use is to be accomplished.
When the tree box filter devices are made operational will depend on a variety of
unique site conditions and should be evaluated and determined on those
conditions.
When
the Filterra™ system is to be used in conjunction with or as an infiltration device
the preparation of the infiltration trench below the concrete box and type
of stone used or filter fabric should conform to the construction
specifications of Infiltration trenches applicable in your area. Placement
of the concrete container must be on an acceptable base (gravel,
sand or compacted soil) to prevent the device from settling. The
container should be backfilled and compacted in the same manner as any precast concrete structure. The under drain leaving the
box and connecting to the receiving conveyance system should be
appropriately supported to prevent deflection during backfilling operations
and sealed at the connection points to prevent any leakage.
