drenotube® installation guide – RAINWATER INFILTRATION
Important ! – drenotube® may be installed on sites that meet all local criteria for the installation of rainwater infiltrative trenches. Soil has to be permeable in order to infiltration to occur. Clay or limestone soils are not suitable for drenotube® Hold recomended distance to buildings to avoid negative impact of water on the building foundation (at least 6m). Distance to groundwater should be at least 1 – 1,5 m. The product must be installed in compliance with any local health department rules or design requirements. Take into consideration that these requirements may imply the modification of the installation steps mentioned below.
Roots find for water an can damage any drainage system. If necessary use herbicides and sub-surface screen foils to avoid roots from coming into the pipe. Use the same techniques as for a traditional drainage.
1. Identify and Mark infiltrative area
Determine where infiltration needs to be placed (hold recomended distance to building foundation or any other superstructure), size and layout for the drenotube® system. Mark off the infiltrative lines before digging. Distribute and size lines according to rainwater flow peaks.
2. Digging the Trench
As any infiltration system intended to transport fluid by gravity, the trenches for the system must be downgrade from the filtration / sedimentation system or from the harvesting tank. The trench where drenotube® is placed shall be level in all directions (both across and along the trench bottom) with drenotube® pipes interconnected, without any dams, stepdowns or other water stops.
The trench shall be dug to a width between 35 to 40 cm for IF300L3/6 or 40 cm for IF370L3/6 – A narrow trench not only saves labor in excavation, but also provides better load-bearing capacity after backfilling is complete. Choose SN4 or SN8 (ring stiffness) according to trench depth however never exceed the ring stiffness of the corrugated pipe.
In case to choose another configuration to allocate adjacent bundles then the trench needs to be wider.
|drenotube®||Maximum pressure1 kPa||Minimum backfill cm (without live load)2||Minimum backfill cm (with live load)||Maximum trench depth m||Trench width cm|
|DR300SN04||50 / 60||60||80||3||40|
|DR300SN08||100 / 120||60||80||5||40|
|DR370SN04||50 / 60||60||80||3||45 to 50
|DR370SN08||100 / 120||60||80||5||45 to 50
(1) Never exceed the ring stiffness of the corrugated pipe. Do not pass over the trench with heavy machinery during installation.
(2) Movable loads like people walking or traffic.
Cross section of different possible trench configurations. A wider trech allows a higher infiltrative capacity. The minimum backfill depth is 60 cm.
Connection of the drenotube® draining segments.
Remove the drenotube® protective shipping bag prior to placing bundle in the trench. Remove any plastic bags in the trench before system is covered. Place the drenotube® units end to end along the top of the trench. Units are printed longitudinally with a line displaying the words “This side up”. Segments must be installed positioning this line upwards. The uncovered part (1/4) must be placed facing the bottom of the trench. Connect the pipe with the external coupling being sure that they are fully inserted to insure proper coupling. In case you need a shorter segment to end the installation units can be cut and retied with the original tie, wire or duct tape. Excess beads can be dumped into the trench. Cover the end of the pipe line with an end-cap to prevent soil or sand from getting into the drainage line.
Placement in the bottom of the trench.
Drop bundles into the trench (be sure to precisely position “This side up” upwards). drenotube® bundles are flexible and can fit in curved trenches as it may be necessary to avoid trees, boulders, or other obstacles. The center-most units containing the pipe are joined end-to-end with an external pipe coupler. In case to use outer units, without pipe, then shall be butted against each other and do not require any type of connection.
Trench closure / Backfilling
Before backfilling the trench be sure there is no plastic bags on top of the drenotube® Check again the longitudinal line displaying the words ” This side up” is positioning upwards. Fill the trench with a permeable soil. Do not backfill with impervious soils like limestone or clay. Backfill can be compacted by either manual or mechanical means and by layers. Never exceed the ring stiffness of the corrugated pipe. The minimum soil cover needs to be 60 cm.