Difference between revisions of "Pipes"

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[[File:Perforations.png|thumb|Pipes are available with perforations on just one side, these should be situated on the lower half of the pipe. Pipes with 360° perforations should have a strip of geotextile or membrane placed over the pipe to reduce the migration of fines from overlying media.]]
<li>Perforated pipes should be continuously perforated, smooth interior HDPE (or equivalent material) with a minimum inside diameter of 100 mm. Where freezing is a concern, horizontal underdrain pipes should be over-sized to a minimum 200 mm diameter. </li>
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Perforated pipes are a common component of [[underdrains]], [[infiltration trenches]] and [[exfiltration trenches]].
<li>Perforations should be 10 mm in diameter and distributed at least every 90 deg around the pipe.</li>
 
<li>All underdrains should be capped on the upstream end.</li>
 
<li>At least one vertical well per BMP is recommended, for inspection and monitoring water level. Well(s), of 100 - 150 mm diameter perforated pipe, should extend to the bottom of the facility. Where a horizontal underdrain is being installed, an upstream and a downstream well should be coupled to the underdrain pipe. The pair of wells can then be used to flush out the length of underdrain if required. The exposed tops of all wells should be fitted with lockable caps.</li>
 
<li>Non-perforated pipes should be used for conveyance to and away from the facility, including overflow. </li>
 
<li>To function correctly, overflow pipes must be larger in diameter than inlet pipes. </li>
 
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Pipes should have been manufactured in conformity with the latest standards by the Canadian Standards Association (CSA) or ASTM International.
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*Perforated pipes should be continuously perforated, smooth interior HDPE (or equivalent material).
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**Wherever possible pipes should be ≥ 200 mm internal diameter to reduce potential of freezing and to facilitate inspections and maintenance with a push camera.
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**Smooth interior facilitates inspection and maintenance activities; internal corrugations can cause cameras or hydrojetting apparatus to become snagged.   
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**A perforated pipe with many rectangular slots has better drainage characteristics than a pipe with similar open area provided by fewer circular holes <ref>Hazenberg, G., and U. S. Panu (1991), Theoretical analysis of flow rate into perforated drain tubes, Water Resour. Res., 27(7), 1411–1418, doi:10.1029/91WR00779.</ref>.
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*Non-perforated pipes should be used for conveyance to and away from the facility, including [[overflow]]. It is good practice to extend the non-perforated pipe approximately 300 mm within the reservoir or practice to reduce the potential for native soil migration to clog the pipe at the interface.
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<gallery mode="packed" widths=200px heights=200px>
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Perforated Pipe 550x550.jpg|Pipe with slotted perforations
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Pipe with connector.jpg|Perforated pipes awaiting installation, note the 30 degree connector used to facilitate maintenance.
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</gallery>
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See also: [[flow through perforated pipe]]
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[[Category:Materials]]
 
[[Category:Materials]]

Revision as of 22:11, 21 April 2020

Pipes are available with perforations on just one side, these should be situated on the lower half of the pipe. Pipes with 360° perforations should have a strip of geotextile or membrane placed over the pipe to reduce the migration of fines from overlying media.

Perforated pipes are a common component of underdrains, infiltration trenches and exfiltration trenches.

Pipes should have been manufactured in conformity with the latest standards by the Canadian Standards Association (CSA) or ASTM International.

  • Perforated pipes should be continuously perforated, smooth interior HDPE (or equivalent material).
    • Wherever possible pipes should be ≥ 200 mm internal diameter to reduce potential of freezing and to facilitate inspections and maintenance with a push camera.
    • Smooth interior facilitates inspection and maintenance activities; internal corrugations can cause cameras or hydrojetting apparatus to become snagged.
    • A perforated pipe with many rectangular slots has better drainage characteristics than a pipe with similar open area provided by fewer circular holes [1].
  • Non-perforated pipes should be used for conveyance to and away from the facility, including overflow. It is good practice to extend the non-perforated pipe approximately 300 mm within the reservoir or practice to reduce the potential for native soil migration to clog the pipe at the interface.

See also: flow through perforated pipe


  1. Hazenberg, G., and U. S. Panu (1991), Theoretical analysis of flow rate into perforated drain tubes, Water Resour. Res., 27(7), 1411–1418, doi:10.1029/91WR00779.