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When considering a (particular) Suction Outlet Cover for a swimming pool or spa, one must be certain that the hydraulic profile of the cover you are considering is safe for the application and meets the Federal/State law.

Until now, unless you are an Engineer or a Mathematician, calculating a specific flow rate was a mathematical nightmare. Most Suction Outlet Cover manufacturers do not provide all three aspects of the hydraulic equation when they disclose the hydraulic profile of their cover(s). They usually state the certified Flow (Gallons Per Minute [G.P.M.]) and Open Surface Area (sq. in.) and neglect the Velocity (Feet Per Second [F.P.S.]). For example, a manufacturer "X" states their Suction Outlet Covers have been certified @125 g.p.m. and have an open surface area of 8.1 sq. in. They (Manufacturer) neglect to mention that this certified Flow rate is at 4.95 f.p.s.

Now with the Drainsafe® Calculator, anyone can determine any aspect of the hydraulic triangle providing they have any two of the necessary data points. In addition to the Drainsafe® Calculator, you can determine the Flow Rate at 1.0 f.p.s. which is regulation for the state of Michigan or 1.5 f.p.s.which is regulation for the state of Florida.

For instance, should Manufacturer "X" Suction Outlet Cover be required to 1.5 f.p.s. all one needs to plug into the chart is the Open Surface Area (sq. in.).

Example (Small open surface area Suction Outlet Cover): 8.1 sq.in. @ 1.5 f.p.s. = 37.87 g.p.m.

Thank you,

Download latest Excel version: http://www.newwatersolutions.com/calhyd.2.xlsx
Download 97-03 Excel version: http://www.newwatersolutions.com/calhyd.xls