Weir & Orifice Calculator
The Weir and Orifice Calculator is used to determine the inlet capacity
in sag (ponding) conditions by use of the Weir and Orifice equations. Knowing
this information will allow you to select the proper grate type and size
for your specific job or project.
Weir Flow Calculations
Weir Equation: Q = 3.3P(h)1.5
Orifice Flow Calculations
Orifice Flow Equation: Q = 0.6A
- Q = Capacity in CFS
- A = Free open area of grate in sq. ft.
- g = 32.2 (feet per sec/sec)
- h = Head in feet
- Orifice Information
- Select a catalog number (will automatically fill in Open Area and Perimeter)
or enter your own values
- Enter head value
- Click "calculate"
The results will determine automatically if your situation falls into
a Weir, Transitional or Orifice flow. Additionally, Neenah grates which
fall within the parameters chosen will appear below the calculator.
For additional information regarding Neenah Inlet Grate Capacities, please contact Ryan Bonell P.E., at (920) 729.3463 or email at firstname.lastname@example.org,
or Joe Falle P.E., at (920)729.3653 or email at email@example.com.