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.]]
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Perforated pipes are a common component of [[underdrains]] used in [[bioretention]], [[permeable pavements]], [[infiltration trenches]] and [[exfiltration trenches| exfiltration systems]]. 
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<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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<li>Perforations should be 10 mm in diameter and distributed at least every 90 deg around the pipe.</li>
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Pipes should be manufactured in conformity with the latest standards by the Canadian Standards Association (CSA) or ASTM International.
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<li>All underdrains should be capped on the upstream end.</li>
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*Perforated pipes should be continuously perforated, smooth interior HDPE or PVC.
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<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>  
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**Wherever possible pipes should be ≥200 mm internal diameter to reduce potential of freezing and to facilitate push camera inspections and cleaning with jet nozzle equipment.  
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<li>Non-perforated pipes should be used for conveyance to and away from the facility, including overflow. </li>
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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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<li>To function correctly, overflow pipes must be larger in diameter than inlet pipes. </li>
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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 of stormwater to and from the facility, including [[overflow]]. It is good practice to extend the solid pipe approximately 300 mm within the reservoir or practice to reduce the potential for native soil migration into the pipe.  
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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 45 degree couplings used to facilitate push camera inspection and jet nozzle cleaning.  
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See also: [[Flow through perforated pipe]]
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[[Category:Materials]]
 
[[Category:Materials]]

Latest revision as of 18:03, 6 August 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 used in bioretention, permeable pavements, infiltration trenches and exfiltration systems.

Pipes should be 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 PVC.
    • Wherever possible pipes should be ≥200 mm internal diameter to reduce potential of freezing and to facilitate push camera inspections and cleaning with jet nozzle equipment.
    • 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 of stormwater to and from the facility, including overflow. It is good practice to extend the solid pipe approximately 300 mm within the reservoir or practice to reduce the potential for native soil migration into the pipe.

  • Pipe with slotted perforations

  • Perforated pipes awaiting installation, note the 45 degree couplings used to facilitate push camera inspection and jet nozzle cleaning.

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.

Filter fabric that is installed to separate dissimilar soils and provide runoff filtration and contaminant removal benefits while maintaining a suitable rate of flow; may be used to prevent fine-textured soil from entering a coarse granular bed, or to prevent coarse granular from being compressed into underlying finer-textured soils.

Soil particles with a diameter less than 0.050 mm.

The natural ground material characteristic of or existing by virtue of geographic origin.

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