9512 EVERGREEN WAY 2022-08-29 - Laserfiche WebLink

The minimum size filter surface -area for use in eastern Washington is determined by using the design water quality flow rate (as determined in item 3, above) and the Infiltration Rate from the table above (use the lowest applicable Infiltration Rate depending on the level of treatment required). Calculate the required area by dividing the water quality design flow rate (cu-ft/sec) by the Infiltration Rate (converted to ft/sec) to obtain required surface area (sq ft) of the Filterra unit. 9. Discharges from the Filterra" units shall not cause or contribute to water quality standards violations in receiving waters. Approved Alternate Configurations Filterral Internal Bypass - Pipe (FTIB-P) The FilterraU Internal Bypass — Pipe allows for piped -in flow from area drains, grated inlets, trench drains, and/or roof drains. Design capture flows and peak flows enter the structure through an internal slotted pipe. FilterraTt inverted the slotted pipe to allow design flows to drop through to a series of splash plates that then disperse the design flows over the top surface of the Filterra*' planter area. Higher flows continue to bypass the slotted pipe and convey out the structure. 2. To select a FTIB-P unit, the designer must determine the size of the standard unit using the sizing guidance described above. Filterral Internal Bypass — Curb (FTIB-C) The Filterra" Internal Bypass —Curb model (FTIB-C) incorporates a curb inlet, biofrltration treatment chamber, and internal high flow bypass in one single structure. Filterra® designed the FTIB-C model for use in a "Sag" or "Sump" condition and will accept flows from both directions along a gutter line. An internal flume tray weir component directs treatment flows entering the unit through the curb inlet to the biofiltration treatment chamber. Flows in excess of the water quality treatment flow rise above the flume tray weir and discharge through a standpipe orifice; providing bypass of untreated peak flows. Americast manufactures the FTIB-C model in a variety of sizes and configurations and you may use the unit on a continuous grade when a single structure providing both treatment and high flow bypass is preferred. The FTIB-C model can also incorporate a separate junction box chamber to allow larger diameter discharge pipe connections to the structure. 2. To select a FTIB-C unit, the designer must determine the size of the standard unit using the sizing guidance described above. Filterral Shallow The Filterra'"' Shallow provides additional flexibility for design engineers and designers in situations where there is limited depth and various elevation constraints to applying a standard Filterra® configuration. Engineers can design this system up to six inches shallower than any of the previous Filterra unit configurations noted above.