Installation of rain (storm) sewerage. How to choose a drainage funnel for a roof and correctly install the system Drainage funnel for a flat roof performance
This article will tell you how and why you need to install drainage funnels for flat roof. After reading, you will learn what funnels are, what they consist of, and will also understand the basic principles of their installation. This information will help you decide design features of the building under construction at the design stage.
Why are gutters needed on a flat roof?
Water does not linger on roof slopes. However, if the building has a flat roof, heavy amounts of precipitation will accumulate on it during rain and snowfall. They can lead to the destruction of waterproofing, accumulation of dirt and even roof collapse. In addition, wind and rainwater can carry plant seeds onto the roof. As they sprout, they will further increase the load on the roofing surface.
Gutter for a flat roof - types, design features and materials of manufacture
The water intake funnel for a flat roof is made of the following materials:
Plastic funnels made of polyvinyl chloride.
Metal zinc coated. This is the most common material for making funnels. It is inexpensive and does its job well.
Copper. This material is not popular due to the high cost of products.
Funnels are:
Flat. Such funnels are installed on flat roofs that are planned to be used frequently. If the roof is covered with asphalt or tiles, they are mounted level with them. flat funnels.
Bell-shaped. They have a protective filtration mesh. This mesh protects the drain from clogging. Its shape is a cap rising above the roof level.
Funnels can have a horizontal or vertical outlet. The difference between them is the location of the drain hole relative to the facade of the building. Funnels with horizontal release have a discharge pipeline that passes through the insulation layer. Such funnels are not very convenient, because when performing technical work Replacing drainage pipes or funnels requires opening up a significant area of the roof. If you lay a horizontal line above the frost line, ice jams may form in the pipes. Ice plugs in pipes can lead to leaks and water stagnation. The horizontal system is used on roofs that do not have an attic. On ordinary flat roofs, funnels with a vertical outlet are used.
A heating cable can be connected to the funnel. Thanks to this, the snow around will melt.
You can find funnels of combined designs.
Structure of a drainage funnel
A typical funnel consists of:
clamping ring, which fits tightly to the roof and ensures tightness;
gratings, preventing objects from entering the drainage system;
horizontal or vertical pipe;
water intake, transmitting water flows into pipes;
oil seals, strengthening the places where the pipe connects to the pipe;
fixing flanges;
covers on top of the product.
Gutter for flat roofing - types and installation methods
Installation is divided by type of installation:
External structures, which are installed around the perimeter of the house.
Domestic, which are laid during construction inside the walls and pass into the sewer. The tightness of such systems cannot be neglected. The result of poor quality work will be the rapid occurrence of corrosion processes.
In the case of a flat roof, installing an internal drainage funnel is the most preferable solution. Horizontal pipes are laid under waterproofing and insulation.
Drainage systems can be:
gravity-fed, that is, with a slope: water flows under the influence of gravity;
vacuum without a slope: they work according to the principle cistern, for which they received a second name - “siphon”.
Flat roof drains: installation and heating
Funnels are installed to ensure that water flows into drains under the influence of gravity. They should be located in the lowest areas of the roof. To ensure water drainage, a roof slope of 2% is sufficient. If such a slope is absent, then it is created artificially - for the entire roof or a so-called “slope” is made - using expanded clay, insulation slabs or concrete.
The roof surface is divided into equal areas of regular geometric shapes. The lower part of the product is mounted into the base of the roof to connect the funnel to the drainpipe. After the waterproofing and insulation have been laid, the lower and upper parts of the funnel are connected using an o-ring seal. A plastic funnel apron should be located between the layers of roofing felt. It is secured with an additional bitumen apron. From above, all these layers are covered with mastic or again with bitumen. A protective grill is installed.
They check the quality of the work done by throwing out a bucket of water at a distance of 2 meters from the funnel.
Calculation of drainage funnels on a flat roof
At least 2 funnels should be installed on the roof of the house to provide the necessary protection in case of unforeseen situations such as severe weather or blockages in the pipes. One funnel should be every 150 or 200 square meters roofs. The funnels are installed at a distance of 25 meters from each other if the length of the house itself exceeds 25 meters. The minimum distance from funnel to funnel is 50 centimeters. The funnel must not be installed closer than 1 meter to the edge of the roof.
If the building is divided into sections, each of them must be equipped with its own funnel storm sewer on the roof.
On our website you can get acquainted with the most . In the filters you can set the desired direction, the presence of gas, water, electricity and other communications.
Principles for selecting and installing a roof drain
When installing roof drains for flat roofs, you need to keep a few things in mind: simple rules. Without compliance with them, the efficiency of drainage structures will drop sharply:
Install on a roof made of metal profiles or seams metal funnels.
For roofing made of bitumen or on polymer coatings, you should choose polymer funnels.
The connection between the funnel and the roof must be completely sealed. To do this, you can glue an additional waterproofing layer, extending it directly on the sides of the funnel. If there are several layers of waterproofing on the roof, the funnel is installed between them.
The funnel must have removable cover and protection from dirt so that the latter does not fall into the drain. In addition, the protection system will help avoid clogging with leaves, branches, sand and other types of street debris.
Need to carry out heating to the funnels so that the water in them does not freeze.
Flat roof drainage: specifics of the construction of internal and external options
The drain can be built outside and inside the building. Each of these methods has its own characteristics. For example, internal structure does not affect appearance buildings, and the external one is easier to install and repair.
Internal drain
In order to properly install an internal drainage system, it must be designed in advance. The pipeline path should be as short as possible, and the connection point with the storm sewer should be convenient and reliable.
Risers can be located near living rooms. In this case, you will not have to install heating on the section of the pipe that passes through the rooms. Wiring is done through grooves, ducts or shafts. It will be necessary to insulate the drain going through the attic.
If the building is not heated, you will have to solve the problem of heating the pipes in order to avoid freezing of the water that will flow into them. This is usually done using a heating cable. It is necessary to provide the riser with a cleaning inspection at a height of one meter from the ground.
On our website you can find contacts construction companies who offer services roof design and repair. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.
Pipes located inside the building are not subject to such sudden changes temperatures like systems built outside. Also, the appearance of the building is not overloaded with additional frills in the form of an external drainage system. This gives the house a neat appearance and makes it easier to decorate the exterior. However, cleaning the internal system is much more difficult.
Water leaves the funnels and risers through special outlet pipes. Branch lines are laid underground or a suspended network is built directly in the house. In order for water to pass through horizontally laid pipes in a suspended network, they are installed with an inclination of 5 millimeters per each linear meter. If you can't install suspension system, you can lay branch lines underground and connect them to the storm sewer. This costs more, and later repairs will be less convenient.
External drainage
External drain suitable for southern regions, where there is little precipitation - no more than 300 millimeters per year. Open system drainage system is easier to clean and repair if it is damaged by bad weather.
The construction of an external drain has many specific features. To avoid damage and corrosion external walls buildings with a flat roof, it is necessary to erect protective sides. The coverings of these sides must be metal or concrete.
Special holes are made in the sides to bring the drainage gutters out. A galvanized apron must be applied to the joints of the side coverings. This will prevent water from penetrating into the cracks between the joints.
Gutters extend beyond the house and roof. In contrast, for internal drainage, funnels are placed on the roof itself, at a distance from the edges.
Video description
Internal drainage funnels for flat roofs:
Drainage systems located outside can be:
Unorganized. This option is suitable for dry areas. Water is drained along the overhangs on the eaves.
Organized. In this case, precipitation is collected in external funnel with guide sides. Also, water can drain into a gutter, from which liquid is drained into a storm drain or directly into the ground.
In some cases, filtering equipment is installed in the drainage system, which makes it possible to obtain process water, which can be used, for example, to operate toilets.
Video description
In the video you can see a drainage funnel for a flat roof:
Conclusion
Understanding the wide range of drainage outlets and technical details can be difficult at first. To accept correct solution, determine your priorities and goals for your drainage system and drains. The choice will narrow significantly when it becomes clear what specific results you want to achieve at the end of the work. If a lot of snow falls on the roof during the winter, it is clear that it will be necessary to install an anti-icing heating system. If the gutters extending beyond the walls do not fit into the design of the building, it is clear that it would be preferable to hide the drain.
To calculate and install the drainage system, the most the best option will contact specialists. Building codes contain a lot of nuances that in any case will need to be taken into account for security purposes. Professionals will help you calculate an estimate based on your needs and will complete all work quickly and with a guarantee.
Drainage systems are divided into open and closed. Open is what we see on most pitched roofs: a gutter runs along the perimeter of the roof, from it water flows into the funnel of the pipe, further down the pipe: into drainage system, into the collector, just at some distance from the facade (so as not to wash away the base and leak to the foundation).
Closed ones are used on flat roofs. Here the angle of the roof is not sufficient for water to drain into the gutter. Moreover: flat roofs are often surrounded by a parapet, through which water, in principle, cannot get beyond the roof. In this case, drainage funnels for flat roofs are used. Through them, rain and melt water enters the riser running inside the house.
Funnels are installed at the bottom of a flat roof (a flat roof also has a slight slope). I'll talk a little about these funnels, installation features and selection.
Why are gutters needed on a flat roof?
Without an outflow device, water will stagnate on the roof. There is nothing good about this: water gradually destroys the coating, penetrates into the thickness of the roofing pie, spoils the insulation, and seeps through the ceiling into the house.
If there is no parapet, and the flat roof has a noticeable slope (up to 10 degrees), the drain funnels can be replaced by an external system, gutter + pipe.
Or the worst option: a knot of unorganized drainage from a flat roof. Its only advantage is savings on purchase and installation. Everything else is bad: an unorganized drain erodes the soil near the base and penetrates to the foundation. Streams of water over front door- also not a very pleasant thing.
note
According to SNiP standards, unorganized drainage is permissible only in houses up to five floors in areas with little rainfall, if there is a sufficiently large distance to the roadway and sidewalk. But even in this case, it is harmful to the walls and foundation of the house.If there is a continuous parapet, any external systems drainage systems are not considered in principle.
Device and types
The components of the funnel are a wide side, a cap and a glass.
The systems themselves are divided into two large groups:
- Traditional. There are a lot of pipes in the house, and there are also a lot of funnels. The systems are mounted on overhangs or special ledges located on the roof lows with a slope of 3 degrees. When using such a system, funnels are placed every 25 meters. All of them are connected to one riser.
- Gravity-vacuum. The principle of operation is the ejection effect, in in this case- the ability of one environment to attract another. When a vacuum is formed in the riser, water under the pressure of air masses is drawn into the riser at high speed.
note
The advantages of this system are high throughput, the ability to self-clean pipes, the use of small diameter pipes, and a smaller number of receiving funnels.Calculation of drainage funnels on a flat roof
Funnels are installed based on the calculation of one piece per 150-200 square meters, but not less than two pieces per roof. Those. For small house 10 by 10 will require two, for 15 by 15 also two, for a roof of more than 300 squares - three, etc.
Features of selection and installation
Materials for making funnels are plastic and metal. The choice is usually based on what material the roof is covered with:
- If it is a seam or metal profile roof, then the funnels are also chosen from metal;
- For and polymer coatings funnels made of polymer compounds are preferred.
Installation requirements:
- The connection between the funnel and the roof must be perfectly sealed. It is recommended to lay additional pieces of waterproofing at the joints. Moreover, the insulation should be glued directly to the side of the funnel;
- If there are two waterproofing layers on the roof, the edges of the funnel are placed between them;
- The funnel must be equipped with a removable lid and protected by an umbrella from dirt;
- The cap should be well secured;
- To avoid freezing of water in the riser, it is necessary to heat the drain funnels on a flat roof;
note
To install the funnel, hot bitumen or mastic is used, in addition - mechanical fastening (screws).Who produces drainage funnels and at what price?
Gutters for flat roofs TechnoNIKOL. Diameter 110, 90, 160. With crimp flange, with sheet catcher, with or without heating. Cost from 300 rubles to 4.5 thousand.
SK TUOTE OY (Finland). Diameter from 7.5 to 16 centimeters, price from 800 to 4 thousand rubles.
"Tehnoresurs" (RF). Diameter 11-16. The cost of funnels with a leaf catcher filter, with and without heating, ranges from 400 rubles to 4 thousand.
Installation internal system drainage is orders of magnitude more difficult than installing gutters and pipes on the façade side. Without the appropriate equipment and qualifications, this task cannot be accomplished.
We will help you choose desired type funnels for your roof and we will carry out installation - quickly, inexpensively, competently and with a guarantee.
You can see photo reports of our work with descriptions and costs.
Precipitation has a positive effect on vegetation, helps saturate the earth with moisture, beneficial properties and are needed to fill rivers and reservoirs. But, in addition to useful aspects, precipitation has an inactive effect on buildings. Constant exposure can damage concrete, wood and others Decoration Materials. Therefore, it must be purposefully removed from the roof. For this purpose, a special drainage system is used. Roofing drainage funnels play a big role in it. They are the ones who catch the flow of water and direct it through the pipe system.
What are the features of such funnels? How are they different from each other? How to install them correctly? We will learn the answers to these questions from this article.
Types of roof drains
Depending on the roof design, there are different types drainage system. The roofs themselves can be divided into two large groups:
- Flat roofs.
- Sloping roofs, with different levels stingray
The drainage system is also divided into two types, based on the roof group:
If we talk about funnels in one and another system, then in the first case it plays a crucial role. Her choice should be treated with special attention. Drain funnel in the photo:
It is precisely these funnels for flat roofs that will be discussed, since gutters horizontal type have built-in funnels that do not need to be selected. It's about about gravitational-vacuum systems. This type of vertical drain was invented more than 30 years ago. His homeland is Scandinavia. Now it is widespread not only in Europe, but also in other countries. The principle of operation is simple, it is based on the so-called ejection ability of liquid in pipes. In this case, one medium carries with it another; in the water drainage system it is air. In the riser, gaseous masses begin to move upward. But when it gets into the system waste water, it is directed downward under the influence of gravity, and the air layer is directed into reverse side. This results in a vacuum environment in which moisture begins to flow at high speed into the collector through the pipe system. The movement of water is determined by pressure from air masses, so a slope is not required for its free movement.
Such a system has many advantages:
- High flow rate.
- Can be used to create narrow pipes.
- The structure will clean itself.
- The drain is light in weight.
- For installation, you do not need to do a large amount of excavation work.
The note! If you compare such a vacuum system and a traditional horizontal drain, the difference is immediately visible.
For example, gravity-vacuum funnels, in which the pipe has a cross-section of 75 mm, can pass through about 15 liters of sediment in just 1 second. But the traditional type system is much inferior, since in order to pass 15 liters of water in one liter, you need a funnel with a diameter of 200 mm.
Materials for making funnels
Internal drainage funnels are made from different materials, which have their own characteristics, advantages and disadvantages. Before you buy a funnel, you need to know this information. Here are the materials the system elements are made from:
Having assessed all the features of each type of funnel, you can choose one or another option.
Product requirements for drainage systems
Installation of the system is specified in GOST 25336-82. The main points are related to the throughput of funnels, as well as their number on a horizontal roof. The roof area for one drainage funnel is specified in SNIP 2.04.01-85, in the section “Internal drains”. So it says there that there should be at least two funnels on the roof and in one valley. The greatest distance between them should be no more than 48 m. It turns out that 1 funnel is required for 230 m2. In this case, its diameter should be 10 cm, no less.
Taking these indicators into account, you need to purchase one or more funnels for your home, and then install them. The roof area per drainage funnel is 230 m2, so you won’t have to spend a lot of money. In addition, it is worth paying attention to the fact that the funnel can become clogged with debris. This includes foliage, dust, and cellophane. To prevent them from penetrating the system and clogging it, a special grill is installed on the roof drainage funnel. She performs protective function, without affecting throughput in any way. However, to ensure that the leaves accumulated on the grate do not prevent water from entering the funnel, you will have to look at the drain from time to time.
Types of funnels for flat roofs
There are several parameters by which storm drains for flat roofs are distinguished. Today, companies produce a variety of models, which makes it easy to choose a product for yourself. So the types are as follows:
Important! Sediment funnels have different sections. Be that as it may, the diameter of the funnel and the drain pipe must match. Typically a section of 10 cm is used. This will be enough to redirect all the water from the roof to storm system.
Installation of a funnel on the roof
Before installing the receiving drainage funnel and other elements of the system, the following nuances should be taken into account:
Now you can begin the installation process. It differs a little from each other, depending on roofing and type of funnels. Still, the principle is the same for everyone. We will consider installation on soft roof. The instructions are as follows: - To begin with, a niche should be cut around the technological hole. Most homes already have it.
- Next you need to take the funnel and plant it directly on the concrete. If there is no fold on it, then glue is used.
- Next you need to apply a buty primer.
- After that, a soft roof needs to be laid along the cut niche, and then along the entire perimeter.
- The structure continues to strengthen. The kit includes a fixing ring that needs to be installed in its place and screwed. A hole is cut in the center.
- All that remains is to install a cap or filter grid for the funnel.
More details about installation can be seen in this video:
As for installing a funnel for a vacuum drain, the installation process can be seen here:
Let's sum it up
The drainage funnel is an integral part of any drainage system. Thanks to it, you can efficiently and quickly drain storm or melt water from the roof surface, flat or sloping. Otherwise, the availability of water will negatively affect everyone structural elements. All that remains is to choose one or another version of the funnel for a flat roof and start installing it. If you have any questions, you can ask them in the comments below the article. Experienced specialists will answer them for you.
Sergey Novozhilov - roofing materials expert with 9 years of experience practical work in the field of engineering solutions in construction.
Today, buildings with a flat roof, familiar to industrial and multi-storey buildings, are increasingly found in private housing construction. Such a roof makes it possible to obtain additional space for arranging a terrace, sports ground, swimming pool, garden. To ensure protection of the roofing covering from destruction under the influence of moisture, it is important to provide effective system for drainage of melt and rain water, take care of correct installation and heating water inlet funnels.
Choosing a drainage system
For roofs flat type There are two options for drainage systems:
- Traditional (requires installation large quantity funnels, water flows through the pipes of the system by gravity).
- Gravity-vacuum (features high throughput with a minimum number of communications).
Traditional internal drain . For its effective functioning, it is necessary to properly slope the roof, with funnels mounted at the lowest points. The number of water receivers depends on the size of the roof. The water intake elements are connected using pipes to a vertical drain pipe, through which water from the roof enters the sewer system. It is important to install horizontal pipeline elements with a slope to ensure free drainage of water by gravity.
Gravity-vacuum system. For more than 30 years, it has been actively used in many countries in Europe and the world due to its high efficiency and efficiency. The principle of operation is based on the fact that in a system equipped with a siphon, a vacuum environment occurs, due to which water is sucked from the surface and moves through the pipes at high speed. The advantages of the system include:
- the flow has high speed;
- simplified installation (fewer funnels and communications are required, pipes do not need to be installed at a slope, since water moves through them under air pressure);
- light weight (does not create additional impact on roofing system);
- efficiency (funnels and pipes are used smaller diameter compared to a traditional system without loss of performance);
- ability to self-clean (the throughput of the system does not change over time).
For comparison: a funnel vacuum system with a horizontal outlet of 75 mm, it is capable of passing up to 15 liters of liquid in one second. To provide the same throughput of a traditional drain, you will need to install a funnel with a horizontal outlet of 200 mm.
During heavy rainfall, a large volume of water can accumulate on a flat roof, which the drainage system cannot cope with. To avoid collapse of structures due to excessive load, it is necessary to install a special additional drainage system - a storm drain. It can also serve as the main drain if the latter becomes clogged.
Selecting a drain funnel
Funnels for arranging internal drainage are made of polymers, metal or a combination of materials. When choosing a product, it is important to consider the type of material that is used as roofing on the roof. Metal funnels are used for installation on roofs, covered sheet metal. Polymer products are suitable for installation on soft roofs.
Funnel for flat roof may be round or rectangular, horizontal or vertical outlet. The choice depends on the installation location and roof features. The products differ in design, but in any case it is possible to rigidly attach the funnel to the base of the roof and ensure reliable waterproofing of the fastening point.
Funnels with metal flange are fixed using a clamping method using fasteners made of of stainless steel. Funnels with a polymer flange equipped with sealing collar, are attached with adhesive.
The drainage system must be protected from clogging. To prevent large debris from entering the drain, funnels are equipped with protective covers or nets. Products with flat lids with slots are used on exploited roofs. The lids can support the weight of a person. If you plan to create a “green” roof, it is best to use funnels with a leaf filter in the form of a mesh cap.
The principle of placement of water intakes
Water receivers must be installed in the lowest areas of the roof. It should be evenly distributed over the surface. To prevent the formation of stagnant puddles on the roof, the slope of the surface towards the funnel should be at least 2%, while at a distance of about half a meter to the drain funnel, the slope should be increased to no less than 5%. Changing the slope is achieved by leveling the screed or reducing the thermal insulation layer.
The number of water receivers is calculated in the following way: each funnel should have no more than 200 sq. m. surface, the distance between funnels is at least 50 cm. Minimum diameter pipes - 10 cm. Despite the size of the roof, at least two funnels must be installed on it, or one funnel and a storm drain. This will avoid flooding if the water inlet is clogged.
When calculating the number of water receivers and their parameters, the intensity and frequency of precipitation in a given region is taken into account.
Construction of an internal drainage system: installation of funnels
First option. The most practical to use are composite funnels, the body of which consists of two parts. Due to a certain dynamic reserve, such funnels, unlike rigid structures, compensate for movements of the insulation.
The installation of a water receiver begins with installing the lower part of the composite funnel into a prepared passage hole cut in the roof slab. The lower part is inserted into drainpipe, and the fasteners should not be rigid in order to avoid damage to communications due to temperature deformations.
The outer part of the funnel to create an internal drain is installed from above, passing through the roofing carpet and a layer of insulation, it is inserted into bottom part. There is an o-ring seal between the parts of the funnel. The plastic apron of the upper part should be laid on the lower lining layer of roofing material. An additional lining layer is mounted on top of it and a bitumen apron is fused as the next layer of waterproofing. An outer layer is mounted on top of the apron roofing material, which is inserted into the funnel bowl and fixed with a pressure ring and stainless steel fasteners. On last stage device, a protective grille is installed on the funnel.
Second option. The installation of a water receiver with a pressure flange is carried out in several stages. It is recommended to attach the funnel not to the insulation, but to wooden blocks of a suitable cross-section, securely fixed to the roof base. The funnel is tightly installed in the hole (it must be rigidly fixed), a rubber-bitumen sealing gasket is installed between the flat side of the funnel and the pressure flange, which is laid under the roofing carpet. At the next stage of the device, the metal clamping flange is fixed with special stainless steel fasteners. To install fasteners in a flange, sealing gasket holes are provided on the side of the funnel. At the end of installation, the cover is secured.
The principle of construction of water intake funnels depends on the configuration of the product and the type of roofing. When installing, you must follow the manufacturer's recommendations.
Heating of water receivers
Drain funnels in winter time in cold climates they need heating to prevent the formation of ice plugs in the pipe and adjacent sections of the horizontal pipeline. The freezing depth reaches one and a half meters, so it is recommended to provide heating for these elements of the drainage system.
Freezing of water in pipes and pipes leads to flooding of the roof surface during thaws and snow melting, since ice hidden from sunlight surrounded by a thermal insulator (a layer of insulation in the roofing cake) is the last to melt.
Today, funnels for flat roofs are available for sale, already equipped with a built-in heating system. But by themselves they will not solve the problem: in this case, the ice plug will grow on the outside. Of course, it will melt faster than the internal one, but it can also create a serious problem by cutting off the flow of water to the drain.
To ensure that the water drainage system functions properly all year round, arrange a heating system for the area around the funnel using a self-regulating heating cable for the roof. In this case, the possibility of blocking the drain with ice is eliminated
In addition to the fact that rain and melt water enters the storm drain from the surface of the ground, they are also discharged from the roof of the house. These drains are called internal.
In a house, an internal drain drains rain or melt water from the roof through pipelines located inside the building. From these same pipes water flows into external network rainwater drainage (closed outlet) or onto the sidewalk (open outlet).
Installation of drainage funnels
The drain is usually made of pressure asbestos-cement, steel or plastic pipes. In the presence of vibration loads, steel pipes must be used.
Drain funnels can be of several types (example in Fig. 117). Drain funnel consists of a housing installed in the ceiling, a frame, and a grille (cap) for retaining large debris. The funnel is hermetically connected to the roof so that moisture cannot seep in and damage the ceiling. Layer waterproofing material It is fixed with bolts between the body and the frame and sealed with mastic. Today you can find drainage funnels of the following diameters: 80, 100, 150 and 200 mm.
Rice. 117. Drain funnels:
a – flat funnels with gratings; b, c – bell funnels; 1 – grid; 2 – frame; 3 – body; 4 – jet straightener; 5 – cap
Drainage funnels with gratings are usually installed on flat roofs, funnels with caps are usually installed on pitched and flat roofs. Since the funnels are cylindrical in shape, with a strong flow of water, turbulence is formed, thereby reducing their throughput. Therefore, in order to increase their throughput, special stream straighteners are used, which prevent the formation of turbulence at the edge of the drainage funnel and prevent the narrowing of the flow area.
Atmospheric and melt moisture enters the closed drainage network through a storm inlet (example in Fig. 118), which is a well covered with a grate. Storm water inlets can be round or rectangular. The bottom of such a well should have a smooth outline, without a pit for sediment.
The drainage ditch must be connected to a closed network through a well with a settling part.
As a rule, storm water inlets are installed at intersections on the inflow side surface water, on a long stretch of descent or ascent, in low places with a sawtooth profile of the street channel.
Rice. 118. Reinforced concrete storm water inlet:
1 – sidewalk; 2 – grid; 3 – connecting pipeline