Determining Skimmer Size:

• Eight sizes available, ranging from 1½” for small sediment traps to 8” for very large basins.

• Size refers to the maximum diameter of the inlet.  For example, a 4” Faircloth Skimmer® has a 4” maximum orifice size.

• Each Faircloth Skimmer® includes a plug and adjustable cutter for making an orifice (hole) smaller than the inlet to customize the flow rate for the particular basin.

TECHNICAL SIZING INSTRUCTIONS:  To read “Determining the Skimmer Size and the Required Orifice for the Faircloth Skimmer®  Surface Drain” click here.

ONLINE SIZING CALCULATOR:

Instructions:  E nter Volume (in cubic feet) of basin to be drained and Number of Days in the green boxes, hit ENTER to run the spread sheet. The skimmer size and the orifice radius and diameter will appear in the blue box*.  Click here to open the SIZING CALCULATOR*.  For detailed explanation on how to use the Sizing Calculator click here.

BASIN VOLUME ESTIMATOR:  If you do not know the basin’s volume but know the dimensions and depth of a square or rectangular basin, enter the dimensions in the Volume Estimator portion of the SIZING CALCULATOR..

*Caution: This calculator does not take into consideration COMMON SENSE . For example, if the volume entered is even one cubic foot greater that the maximum calculated capacity of a skimmer the next larger size will be given as the answer. In reality a reasonable judgment would be that the smaller size is adequate given the room for error in the assumptions that go along with the design and sizing process. Therefore it is recommended that the following chart be used together with the spread sheet.

FLOW CAPACITIES (in Cu. Ft.) FOR THE Faircloth Skimmer®

Important note: The orifice sizing chart in the Pennsylvania Erosion Control Manual DOES NOT APPLY to Faircloth Skimmer® surface drains. It will give the wrong size skimmer. Please use these instructions to choose the size skimmer required for the basin volume and the orifice size.