How to choose a design drainage channel for the evacuation of run-off water?
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Rainwater drainage: drainage channel, yard drain and a design look in accordance with the aesthetics of your outdoor…
The European standard EN 1433 CE defines, in particular, the installation rules of drainage channels for water evacuation (rainwater) in the circulation zone used by pedestrians and vehicles. The standard features the materials, rabbets, gratings and imposes stress and sealing tests of the drainage channels. A multitude of requirements related to rainwater harvesting for the housing.
Credit Pictures ULMA ARCHITECTURAL
The resistance of a drainage channel will depend on the composition of the drainage channel structure (channel + grating) and of the installation method used. In this article, we are interested in drainage channels for surfaces, areas and zones used exclusively by pedestrians or cyclists (standard code A15) in their residential area. The channels must withstand 15 KN (A15 Class) for the pedestrians (terraces, patios, garden circulation aisles, pools) and 125 KN (B125 Class) for the driveways, courtyards and light vehicles private parking (according the DIN 19580 standard).
Integration of the channel into its environment
There are 4 main channel integration solutions
- The grating remains visible: the channel is at the same level as the 2 surfaces it separates.
- The grating is very thin and almost invisible: called slot gratings.
- The decorative grating: by placing a decorative grating on the top of the channel. This decorative openwork element can allow an aesthetic union between 2 surfaces (between 2 facings / natural stone) on either side of the channel.
- Total absence of grating
Main types of channels and aesthetic solutions for outdoor water drainage
Credit Pictures ACO HEXDRAIN BRICKSLOT
The Slot gratings. The channel structure is made of Polymer concrete or PE-PP. A slot lid (or cover) is placed on its upper part, which minimises its visible surface for a functional, discrete (almost invisible) and aesthetic drainage. The slot can be central or lateral (called symmetric or asymmetric), continuous or discontinuous. This solution adds elegance and value to the building. There is a wide choice of materials for the cover: cast iron, galvanised steel, plastic composite, etc. The slot width is generally 10 mm. The cover is attached to the channel structure by a mounting piece or it’s a monobloc. Warning: Avoid to use it under trees that lose their leaves.
The gladder or mesh type grating drainage channel are the traditional ones. Made of galvanised steel, stainless steel, cast iron, polypropylen. The most common colors: anthracite, sand colour, stainless steel colour, etc. Some manufacturers such as ACO, offer colours according to the customer’s RAL. The mesh grating (grid) is to provide a maximum absorption surface.
Crédit Photos ETERNOVICA
Credit Pictures ACO Wire grating
The ultra design channels with:
- wire grating (stainless steel colour). Simple but aesthetic.
- wood grating (thermally modified oak, ash, acacia). The “eco-attitude” spirit. Perfect for wood terraces.
- voronoï grating (cast iron diamant colour, citrine colour, pearl colour, smoky quartz colour, etc). Resemble crackle patterns, designed by a dried earth.
The Channels without grating. The grating is totally absent. The channel is totally masked, the slot is naturally formed by the spacing between 2 tiles of the coating (pool tiles, wooden strips, etc.). No plastic or metal slot visible. No design or environment disruption. Make sure this type of channel is compatible with the intended coating (paving, flooring, tiling, wood).
Credit Pictures NICOLL Caniveau Invisible Connecto
Domestic drainage channel selection guide
Beyond the aesthetic choice, take into account the following constraints:
- The capacity of the channel based on the volume of water to drain (small, large, standard). This factor depends mainly on the rainfall typology of the dwelling’s geographical area. According to the surface to drain, the manufacturers provide a selection guide corresponding to the engulfing surface of the channel in cm2/ml (so the dimensions).
- The dimensions of the channel (small height, small / large length, useful depth, etc.). For domestic use, the length is from 100 mm to 200 mm, and the heights are from 40 mm to 200 mm.
- The use of the channel according to passage and bearing constraints (so its resistance) and the selection of its grating (gateaway? anti-heel? barefoot? strong resistance?). There are channels for pools, terraces, driveways, etc.
- The implementation simplicity
(the bottom of the extremity or lateral, perforation for vertical outflow, simplicity of embedding, integrated slope, etc.).
- The durability. It depends on the materials used. The concrete+polymer channels are more resistant to frost than a simple concrete channel, they are lighter and waterproof. Synthetic plastic models are distinguished by their ease of implementation (lightness) and their resistance in the case of chemical fluids (oils, greases). The cast iron gratings are more resistant to driving.
- The respect of the environment in the materials used. Plastic channel: choose a recyclable polyethylene.
- The aesthetic aspect by the choice of materials of the grating cover: stainless steel, cast iron, galvanised steel, zinc, plastic polymer, wood, etc.
Other constraints specific to the construction site may be studied:
- Flow regulator channel.
- Channels for window wells.
- Channels for pools, barefoot walking, anti-blocking heel (anti-heel mesh – 33 x 11 mm), etc.
- Channels specific for the evacuation of certain liquids (fuels, oils, alkaline liquors and fats, etc.).
Crédit Photos Guide de choix ACO
General installation principle of a domestic drainage channel
The bodies of the channels must be positioned on a concrete sole. The laying principles will vary according to the nature of the soil and work. Refer to manufacturer’s documentation.
- The bodies of the channels must be positioned on a concrete sole of at least 10 cm high over the entire width of the channel or according to circumstances over the width of the trench (bottom foundation trench). The concrete sole should be accomplished before the installation of the channels. Using a ruler and a level, make sure to comply with a slope towards the evacuation of 1 cm per meter along the entire length, consistent with the final coating (paving, tiles, etc.).
- Break the vertical and/or horizontal output pre-marks and connect the first channel to the connection point and evacuation (to siphon).
- Connect the channels to each other by interlocking the rabbet joints and by performing a seal made of elastomeric sealant. Attach the covers (gratings) if necessary (progressively to stiffen the whole) depending on models.
- A the end, attach the cap or cleanout cover.
- Chock the channels by filling the trench with the intended material (concrete, thin screed, etc.).
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