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Weir Box Mounting

Openchannelflow stainless steel dam seepage weir boxOpenchannelflow Weir Boxes are designed to measure above grade and shallow burial flows.  Regardless of the application most Weir Boxes should be mounted to a concrete slab to ensure that it is secure and does not shift out of position.  Each Openchannelflow Weir Box is provided with stainless steel anchoring feet to help accomplish this.

In above grade applications where the floor of the Weir Box must be higher than the surface grade, Openchannelflow can provide custom fabricated stainless steel stands.

For below grade applications where a weir is needed, Openchannelflow manufactures fiberglass Weir Metering Manholes.


Weir Box End Connections

Openchannelflow Weir Boxes can be provided with a variety of end connections, including pipe stubs, flanges, and caulking collars to connect to piping.  

For applications where the flow need only spill out (or in) of the Weir Box, the box body can be configured for this.

Pipe Stubs

pipe stub connection on an Openchannelflow fiberglass weir boxThe most common method of bringing flow into / out of a weir box is the pipe stub.  The flexibility of the Weir Box design means that multiple inlet / outlet stubs can be accommodated as well as stubs of varying size.  Pipe stubs can enter / exit the Weir Box horizontally or vertically.

The connection between the Weir Box pipe stub(s) and the inlet / outlet piping is made with a flexible coupling (Fernco). This coupling (typically made of flexible PVC although EPDM, Neoprene, and Sanoprene are also available) provides a water tight seal and is held in place by stainless steel hose clamps.


flange connection on an Openchannelflow fiberglass weir boxFlanges are another way of bring flow into / out of a Weir Box.  Flanges may be raised face (PVC / stainless steel) or flat faced (fiberglass).  

Regardless of construction – Weir Box flanges are NOT for pressurized applications as the Weir Box will not operate under pressurized conditions.  

Gasketing and connection hardware is by others.

Caulking Collars

Essentially oversized pipe stubs, caulking collars allow a smaller pipe to be inserted into a larger pipe (with the resultant annular space filled with a material such as oakum or hydraulic grout).  Caulking collars allow for much great differences in pipe slopes than pipe stubs or flanges allow.