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Scupper Size Formula:
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Scupper size calculation determines the appropriate drainage opening size needed to handle a specific water flow rate at a given velocity. This is critical for effective roof drainage and preventing water accumulation.
The calculator uses the scupper size formula:
Where:
Explanation: The formula calculates the cross-sectional area needed to allow water to flow at the specified rate without causing backup or overflow.
Details: Correct scupper sizing is essential for effective roof drainage, preventing structural damage from water accumulation, and meeting building code requirements for drainage capacity.
Tips: Enter flow rate in gpm and velocity in ft/s. Both values must be positive numbers. Typical velocities range from 2-5 ft/s for most drainage applications.
Q1: What is a typical flow rate for roof drainage?
A: Flow rates vary based on roof size and rainfall intensity, but typically range from 10-100 gpm for most residential and commercial buildings.
Q2: Why is velocity important in scupper design?
A: Proper velocity ensures efficient water movement without excessive turbulence or the potential for debris accumulation in the scupper.
Q3: How do I determine the flow rate for my specific application?
A: Flow rate is calculated based on roof area and expected rainfall intensity for your geographic location, typically using local building code requirements.
Q4: Are there standard scupper sizes?
A: Yes, scuppers come in standard sizes, but custom sizes can be fabricated. Common sizes include 4x6, 6x6, and 6x8 inches.
Q5: Should I include a safety factor in my calculation?
A: Yes, it's recommended to include a safety factor of 1.5-2.0 to account for potential clogging and extreme rainfall events.