This document discusses how the choice of pipe material influences drain spacing and system cost. It finds that pipe with more rows of perforations, such as an 8-row regular perforated pipe, has a higher effective radius than a 4-row pipe, allowing for wider drain spacing. Experiments show that a sock-wrapped pipe has the highest drain inflow of the pipes tested, both with and without drain sedimentation present. The key takeaways are that the number of perforation rows and slot length most impact effective radius and drain flow, and a sock-wrapped pipe performs best in terms of drain inflow and spacing.

1. Choice of Pipe Material Influences
Drain Spacing and System Cost
Ehsan Ghane
Assistant Professor and Extension Specialist
@MSUEhsanGhane

2. Effective Radius (Re) of a Drain Pipe
• Effective radius is the radius of an imaginary pipe with a completely
open wall
–Effective radius accounts for entrance head loss
• Dierickx (1999): Analytical Eq.
• Re is used
–DRAINMOD and RZWQM2
–Estimate drain spacing with Hooghoudt
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3. Rows of Perforations
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4. 6
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Sand-Slot Pipe
Regular-Perf Pipe

5. Two Pipe Choices: Drain Sedimentation Issue
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6. Pipe Manufacturers
• ADS (Michigan plant)
• Baughman Tile (Ohio)
• Fratco (Indiana)
• Haviland Drainage (Ohio)
• Prinsco (Minnesota)
• Springfield Plastics (Illinois)
• Timewell Drainage (Illinois)
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7. Effective Radius (Re) of Pipe (Rows of Perforation)
• 4-inch, 4-row regular-perf pipe
–Re = 0.3 to 0.9 cm (average 0.6 cm)
• 4-inch, 8-row regular-perf pipe
–Re = 1.9 cm
• Most important: Rows
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8. Effective Radius (Re) of Pipe
• 4-inch, 4-row regular-perf pipe
–Re = 0.3 to 0.9 cm (average 0.6 cm)
• 4-inch, sock-wrapped pipe
–Re = 5.9 cm
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9. Sand-Tank Experiment
• 4-row sand-slot pipe, 8-row sand-slot pipe
• Regular-perf pipe wrapped with knitted-sock envelope

10. Experiment Setup
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11. With Drain Sedimentation:
A Sock-Wrapped Pipe Has The Highest Drain Inflow
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Drain inflow of a sock-wrapped
pipe is 29% higher than the 4-row
sand-slot pipe, when installed at
30-ft spacing and 2.5-ft depth

12. A Sock-Wrapped Pipe Allows For a Wider Drain Spacing
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13. Which pipe properties increase water
entry into the pipe?

14. Myth: Higher Water Inlet Area, Higher Drain Inflow
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15. Greater Subdivision of Openings Reduces Convergence
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16. Take-Home Messages
• Perforation shape and pattern affects Re
• Most Important: Number of perforation rows
–8-row is much better than 4-row, for same price
• Second most important: Slot length
–Longer, narrower slots are better than shorter, wider slots
• Slot width has minimal effect
• With drain sedimentation, sock-wrapped pipe is fastest
• Without drain sedimentation, 8-row reg-perf pipe is fastest
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Length
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18. 43
3-Row Regular-Perf with Sock
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19. Water Passed Through The Sock From All Directions
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