Difference between revisions of "Overflow: Installation"

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[[Overflow|Overflows]] are features of inline facilities and convey larger storm events out of the LID feature.<br>
[[Overflow|Overflows]] are features of inline facilities and convey larger storm events out of the LID feature.


'''Construction Steps:'''<br>
'''Construction Steps:'''
#Connect the overflow drain to the underdrain.
#Connect the overflow drain to the underdrain.
#Fit a metal, domed grate to the overflow.
#Install overflow pit to grade at the location specified in the contract documents.
#Install overflow pit to grade at the location specified in the contract documents.
#Fit a metal, domed grate to the overflow.<br>


'''Key Inspection Points:'''<br>
'''Key Inspection Points:'''
*Overflow drain matches design specifications.
*Overflow drain matches design specifications.
*Overflow pit is positioned at the maximum water surface elevation of the practice, as per the contract documents.
*Overflow pit is positioned at the maximum water surface elevation of the practice, as per the contract documents.
*Sufficient freeboard is provided between the overflow and inlet such that the inlet is not inundated by design storm flows.
*Sufficient freeboard is provided between the overflow and inlet such that the inlet is not inundated by design storm flows.
*Overflow grate matches design specifications.
*Overflow grate matches design specifications.
*Overflow grates located in high-traffic areas are screwed on or equipped with locks.<br>
*Overflow grates located in high-traffic areas are screwed on or equipped with locks.


'''Mistakes to Avoid:'''<br>
'''Mistakes to Avoid:'''
*Backflows – ensure that backflows are avoided by confirming that inlet and overflow elevations match design specifications with surveys.
*Backflows: Ensure that backflows are avoided by confirming that inlet and overflow elevations match design specifications with surveys.
*Incorrect sequencing – install overflow drain prior to backfilling with granular material and engineered soil.
*Incorrect sequencing: Install overflow drain prior to backfilling with granular material and engineered soil.
*Incorrect grate material – avoid using plastic overflow grates due to breakages and UV degradation.<br>
*Incorrect grate material: Avoid using plastic overflow grates due to breakages and UV degradation.


<gallery mode="packed" widths=300px heights=300px>
<gallery mode="packed" widths=300px heights=300px>
overflow-pipe-install.jpg | Overflow pipe installed to an underdrain T-connection.
overflow-pipe-install.jpg | Overflow pipe installed to an underdrain T-connection. (Photo Source: CVC, 2010)
overflow-plastic-cap.jpg | Overflow installed with a plastic cap. Note that the use of plastic grates is discouraged.
overflow-plastic-cap.jpg | Overflow installed with a plastic cap. Note that the use of plastic grates is discouraged. (Photo Source: CVC, 2012)


</gallery>
</gallery>

Latest revision as of 01:33, 29 September 2022

Overflows are features of inline facilities and convey larger storm events out of the LID feature.

Construction Steps:

  1. Connect the overflow drain to the underdrain.
  2. Fit a metal, domed grate to the overflow.
  3. Install overflow pit to grade at the location specified in the contract documents.

Key Inspection Points:

  • Overflow drain matches design specifications.
  • Overflow pit is positioned at the maximum water surface elevation of the practice, as per the contract documents.
  • Sufficient freeboard is provided between the overflow and inlet such that the inlet is not inundated by design storm flows.
  • Overflow grate matches design specifications.
  • Overflow grates located in high-traffic areas are screwed on or equipped with locks.

Mistakes to Avoid:

  • Backflows: Ensure that backflows are avoided by confirming that inlet and overflow elevations match design specifications with surveys.
  • Incorrect sequencing: Install overflow drain prior to backfilling with granular material and engineered soil.
  • Incorrect grate material: Avoid using plastic overflow grates due to breakages and UV degradation.