RTC Southern

Filter Point

Filter Point
(5"FP, 8"FP, 10"FP, 12"FP, 14"FP) The Filter Point style is characterized by the deep cobbled surface. This style exhibits a relatively high coefficient of hydraulic friction (Manning 0.23 to 0.25) and is well suited for attenuation of hydraulic energy. The filter points are created by weaving the top and bottom layers of fabric together. These filter points relieve hydrostatic uplift from ground water in the underlying soil. Filter Point sizes are classified by measuring the diagonal distance between two filter points. The Filter Point style can also be easily vegetated by installing live stakes through the filter points.

5" Filter Point
The lightest in the Filter Point style, the 5"FP is used for constructing thinner revetments in less demanding areas. The nominal thickness of 5"FP is 2.2".

8" Filter Point
The most common size in the Filter Point style, the 8"FP is used where hydrostatic uplift is more of a concern and/or additional weight is recommended. The nominal thickness of the 8"FP is 4".

10" Filter Point
The largest common size in the Filter Point style, the 10"FP is used where sever abrasion is anticipated and additional weight is advised. The nominal thickness of 10"FP is 6".

12" Filter Point and 14" Filter Point
Less frequently used are the 12"FP and 14"FP. These sizes are usually necessary only in the most extreme cases. The nominal thicknesses are 8" and 10" respectively. When deciding if you need the 12"FP or 14"FP, please contact us to make sure you are making the right selection.

Some areas of installation include: drainage ditches, perimeter ditches on landfills, canals, ponds, lakes and reservoirs, headwalls and pipe outlets, spillways and dams.

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