The installation of the drainage system in sewerage construction projects is a delicate operation that requires the utmost care to ensure maximum long-term performance. After analysing the different materials available on the market and all the benefits of plastic channels, attention must be paid to the installation process. We can divide the installation process into two main stages:
- Assembly of the channel
- Laying of the channel
Mounting polypropylene drainage canal
The polypropylene channels can be easily transported and assembled directly on site and, for this reason, the first step is to assemble the grating using the anchor kit. This procedure is divided into 3 steps
- Insert the metal reinforcing rails and assemble the grids (fig.1)
- Screw and tighten the screw and anchors (fig. 2), widen the anchors to an inclination of 45° from the channel (fig. 3)
- Assemble the channels together for the desired length. Each channel must be inserted into the next one all the way until the lip snaps into places (fig. 4)
1. Channels installation process.
Installation of the polypropylene channel
Once the drainage channels have been assembled, the next step is installation. This procedure involves preparing the ground, laying the channels and the backfilling of the sides:
- Dig the trench of the proper size (fig. 1), the land on the bottom should be well pressed.
- Lay a bed of concrete of the recommended thickness (fig. 2).
- Lay the channel on the ground (fig. 3).
- Backfill the sides of the channel with suitable concrete (depending on concrete composition) of the thickness indicated in the laying tables on the SABdrain catalogue (fig. 4). The concrete must be vibrated and rendered with extreme care, must fill all interstices and be compact under the edges of the channel (fig. 5). For the heaviest load classes (E600, F900) a load distribution reinforcement with steel rods is recommended.
- When the concrete is solidified it is possible to proceed with the laying of the floor in asphalt, tiles or cobblestone. During this stage is recommended to cover the grid with a plastic film in order not to soil them.
2. How to install plastic channels.
Installation of channels in different surfaces
In general, the procedure we have listed above is one that can be replicated in many application cases. However, we can distinguish between installation on asphalt (fig. 3 and 4), draining asphalt (fig. 5), concrete slab (fig. 1) and cobblestone (fig. 2).
Dimensions of the channel backfilling
In addition to the different type of surface, what influences the size of the concrete backfill is the intended use of the channel and the resulting load class. Quite simply, the more the channel is subjected to forces and stresses, the more the backfill will increase in thickness.
For example, if we consider concrete with Rck (EN 206-1), we should consider the following dimensions for the backfill:
- Drainage channel A15: width 100mm and height 80mm
- Drainage channel B125: width 100mm and height 100mm
- Drainage channel C250: width 150mm and height 150mm
- Drainage channel D400: width 200mm and height 200mm
- Drainage channel E600: width 200mm and height 200mm
- Drainage channel F900: width 250mm and height 250mm
3. Installation of channels in different surfaces.
Mistakes to be avoided when installing a drainage system
Unfortunately, after the installation of a drainage system, problems such as flooding or waterlogging can occur. For which reasons? We can divide them into three main categories:
- Design errors;
- Wrong choice of materials or product;
- Laying not carried out in a workmanlike manner
Errors in the calculation of the water flow rate may have been made during the design phase, leading the client to purchase channels too small and/or drain pipes with insufficient diameters to ensure proper rainwater runoff.
Wrong choice of materials or product
If the calculations have been carried out correctly, the reason may be the wrong choice of materials. Forces such as water flow and external stresses caused by vehicles or the deteriorating effect of weather and temperature changes can affect the structural stability of channels and of concrete backfill.
Laying process not carried out in workmanlike manner
Disregarding the installation instructions in this article can lead to problems in the drainage system.
Installing channels at the wrong slope can lead to unpleasant rainwater stagnation, while not respecting the specifications of the bedding, the thickness of the backfill or overestimating the bearing capacity of the bottom can lead to failure or breakage of the channels.
4. Error results in the installation of a drainage system.
For more information on how to install drainage channels you can download our installation manual and/or consult our team of engineers and designers for any question or requirement by visiting our contact page.