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Old 03-17-2014, 02:42 PM   #1
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Default Floor drain calculations

To calculate the GPM capacity of a floor drain, I found the following equation:
Q = 448.2 Cd A 2gh where Q = Flow Rate (Gallons per Minute)
Cd = Discharge Coefficient (Typically 0.6)
A = Open Area of Grate (ft2)
g = Acceleration (32.2 ft/s2)
h = Head Above the Floor (ft)

What is meant by head above the floor for h? the floor drain is flush with the floor.

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Old 03-17-2014, 11:14 PM   #2
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If I'm not mistaken the head above the floor is the amount of water buildup on the floor. Engineering mumbo jumbo.
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Old 10-11-2014, 03:23 PM   #3
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Get a code book,each size has a dfu (drainage fixtures units)which is how you size it.
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