Internal drainage system design - calculations and
For a large part of the territory of Russia, abundant rainfall is typical: in winter, prolonged snowfalls, and in summer, prolonged rainfall. Such weather conditions are considered unfavorable, because they often leave the roof standing, and leakage occurs. To cope with the large volume of melt and rainwater accumulating on the roof surface, a drainpipe system is installed, which is responsible for collecting and transporting fluid into the storm sewer. For flat and uncoiled single-pitch roofing, internal drainage is suitable, the device of which we will examine in detail in this article.
Device
Internal drain - a system that collects and removes thawed and rain from the surface of the roof through the drain pipes in the "shower". This design is equipped when the house has a flat or shed roof. The drainage system of internal type consists of the following elements:
- Water intake funnels. This term refers to devices that carry out the primary collection of fluid accumulating on the surface of the roof. The material and price of this element is significantly different: there are inexpensive models of plastic or stainless steel and exclusive of copper. If the roof has a flat surface with a slight slope, in accordance with the requirements of SNiP, a flat funnel of internal drainage is installed on it, on a pitched one - a bell cap. The quantity and diameter of this element determines the calculation, taking into account the area of the slope and the amount of precipitation. Specialized stores sell a heated funnel, protective filters and flow stabilizers, however, the price of such models is much higher.
- Discharge pipes. So called pipes connecting the funnels and drainage riser. The installation of these elements is carried out with a slight slope so that the system functions by gravity. The diameter of the discharge pipe depends on the size of the funnel, the amount of precipitation that determines the calculation, and the requirements of the SNiP. The installation is carried out inside the building, therefore, the elements are joined by welding without compensation elements.
- Drainpipe. A stand is a section of a drainpipe, located vertically inside a building, through which melted snow or rainwater enters a storm sewer. According to the norms of SNiP, the diameter of the riser should correspond to the diameter of the discharge pipe and funnel, since the main cause of leakage is insufficient sealing of the connecting joints between these elements. The roof drainage system works effectively under the condition of complete tightness.
- Fasteners. Installation of the drain of this type is performed inside the building, the system is installed using brackets and fixings. According to the requirements of SNiP, the material of fasteners and pipes must match.
- Audits. The drainage system according to the norms of SNiP includes revision openings through which they perform routine inspection and pipe cleaning.
Note! For high-quality work of internal drainage, unravel a flat roof, this is the name of the process of creating the minimum slope necessary for running water into the funnel. Installation is carried out in such a way that they are located below the roof level.
Varieties
The characteristic difference between the internal and external drainage is the installation site, since the installation is carried out inside the structure. On the one hand, this design provides some advantages, on the other hand, it is associated with difficulties, since each node must be tightly sealed to prevent leakage. The number and diameter of elements determines the calculation based on determining the area of the roof and the amount of precipitation. Internal drainage system is of two types:
- Gravity. The gravity drain type is the simplest option, the calculation and installation of which is carried out without much difficulty. The design includes the following elements: funnels, discharge pipes, risers. The gravity system is inefficient, it will not cope with the influx of water that the roof undergoes during heavy rains if the diameter or number of elements does not match the parameters shown by the calculation. The advantage of this solution is low price.
- Siphon Drain, working on the principle of the siphon, differs from gravity higher performance. Siphon drainage system is completely filled with sediments, so that in it from the water intake funnel and before entering the sewage water column is formed. If the liquid level in the riser drops, then a vacuum zone is created in the funnel, sucking moisture from the roof surface. The cost of installing this type of drain is higher due to the cost of special funnels with flow stabilizers. To work effectively, you must perform the calculation, as well as pick up quality material. The advantage of this design is that with the rapid movement of water, each drain unit is self-cleaning, regardless of what material is used.
The price of the elements of the internal drain depends on many factors: the value has the material, diameter and fame of the manufacturer. The cheapest models are made from stainless steel. Plastic is slightly more expensive, but SNiP does not allow the use of plastic parts, if the installation is carried out on high-rise or apartment buildings. Components made of copper, cast iron and aluminum are also produced, but they are less popular. High-quality material, which is resistant to corrosion, will extend the life of the drain.
Installation rates
Even if the calculation was carried out correctly, and when installing a quality material was used that complies with the requirements of SNiP, the water drainage system may not work correctly if you install it without observing simple rules:
- Water intake funnels set evenly over the entire area of the slope. If the roof is small, install at least 2 funnels, for every additional 20 square meters. m add one water-catcher element, as required by SNiP.
- Funnels, according to the norms of SNiP, can not be installed closer than 1 m to the walls of the building. The maximum allowable distance between two funnels connected to the same riser should not exceed 20 m.
- If the drain material is metal, pipes and funnels are electrically heated. This measure eliminates the problem of freezing and destruction of pipes in the winter, when a low temperature is established in Russia.
- If the roof is multi-level, and the difference in height between the levels exceeds 4 m, the individual drainage branches, not interconnected, are calculated and installed, since this difference reduces the efficiency of precipitation removal.
- Building codes prescribe to install storm sewers, starting under the drainpipe and ending in designated areas. For private houses it is allowed to drain the drainage water into the ground or collect it in a special container.
The device of internal drainage requires compliance with the strictest tightness, as the leakage of fluid into the connecting seams leads to leakage inside the premises, resulting in the use of the finish. When mounting a drain of this type, do not forget that servicing it is much more difficult.
Video instruction