How to install a fan pipe: step-by-step instructions and analysis of typical mistakes

Fan ventilation design principles

Project of a sewer system with a ventilated riser

When designing fan ventilation, two main requirements should be followed:

• The diameter of the exhaust pipe must not be less than the diameter of the sewer riser.
• The outlet of the fan pipe is carried out in the direction from which the unpleasantly smelling gases will be carried away by the wind.

As a rule, the installation of a fan riser consists in supplying a pipe to the ventilation duct.In the event that this is not possible, the outlet of the vent pipe can be brought out through the wall (also find out which bathroom is better - acrylic or cast iron).

Fan ventilation equipment

Exit of the vent pipe in the roof

Fan ventilation may include the following elements:

• Fan pipes;
• Connecting pipes;
• Ventilation channel;
• Fitting.

Fan ventilation installation tips

Do-it-yourself fan ventilation installation

• The diameter of the exhaust pipe must be equal to the diameter of the riser from which it removes gases.
• For a fan hood, you can use both plastic and cast iron pipes. Fittings are selected according to the pipe material.
• If you plan to use a combination of materials (for example, a plastic fan pipe will be installed on a cast-iron riser), then a rubber adapter should be used.
• If you need to connect several fan pipes, tees with an angle of 45 or 135 degrees are used.
• Horizontal sections of fan pipes are laid with a slope, which must be at least 0.02% and be made in the direction of gas flow.
• If it becomes necessary to change the direction of the vent pipe, then it can only be done above the last device connected to the ventilated riser.
• Changing the direction of the pipe is carried out by installing fan bends with an angle of 135 degrees.

The fan riser itself must meet the following requirements:

• The outlet of the pipe must be carried out above the roof at a distance of at least 0.3 meters from the roofing.
• If the house has a used attic space, then the height of the output should be increased to three meters.
• The distance from the outlet of the fan pipe from the balcony or window closest to it must be at least four meters.
• The riser itself must pass through "warm" rooms or be insulated.
• When using plastic pipes, metal sleeves should be used to organize the output through the ceiling.
• It is forbidden to organize fan ventilation and a chimney in one channel.
• If there are several sewer risers in the house, then the fan pipes can be combined into a single hood so that there is only one outlet on the roof.
• In the upper part of the fan pipe, a cover with a mesh should be installed, which will protect the system from the penetration of insects and rodents.

Typical mistakes when installing fan ventilation

fan fungus

• Some owners of private houses, not wanting to bother with organizing the connection to the pipe on the roof, consider it possible to cut the fan pipe in the attic.
  Such a solution is fraught with the accumulation of gases under the ceiling and their penetration into the premises of the upper floor.
• It is undesirable to mount the fan pipe on an external wall, as this solution will lead to problems with the formation of condensate.
• Some homeowners, in an effort to improve draft in the fan pipe, install a weather vane instead of a protective fungus at the outlet. Such a solution does not give the desired effect and, on the contrary, can worsen the outflow of gases and there will be a problem with the smell of sewerage in the bathroom.

How to make a sewer fan riser: a quick guide

In principle, the installation of fan ventilation does not present any difficulties, unless, of course, the system is installed from scratch.If we are talking about finishing the sewer, then you will have to work a little here - in particular, cut the thickest sewer bed, insert an oblique tee into it and from it lead a pipe of the same diameter as the sunbed, first to the attic, and from there to the roof. Don't forget to put an umbrella on it to block the way of rain water.

That, in principle, is everything you need to know about sewer ventilation. Whatever one may say, but a fan riser is needed, and you should not get rid of it. Apart from trouble, this step will lead to nothing else.

How to determine what installation is required

The fan pipe is an optional, but highly desirable element of the sewer system, which perfectly stabilizes its operation. It is considered that installation is necessary, for all houses with a height of more than one floor

However, when designing sewers, it is important to take into account other secondary factors:

The diameter of the sewer pipes. If the diameter of the pipes of the sewer riser is less than 110 mm, then the sewage pipes for the sewer must be installed, since it is enough to drain the toilet bowl and the bathtub at the same time to fill the full volume of the riser.

If the septic tank is located in the immediate vicinity of the house. Even if the house is one-story, but the sewage tank is too close to it, you need to make sure with the help of a fan valve.
If the layout of the house suggests that it will have several bathrooms or baths that can potentially be used at the same time, then it is better to reduce the risk of a vacuum in the system.
If the house has plumbing fixtures that have a large volume of wastewater, for example, a swimming pool, a jacuzzi, a large bathtub.

Remember that the amount of wastewater is affected not only by the number of plumbing fixtures, but also by the intensity of their use. If there are two bathrooms in the building, located one above the other, but only one family lives in it, then it is unlikely that a fan pipe will be needed, but it definitely will not be superfluous.

When designing the sewer systems of private houses, many factors must be taken into account, ranging from the number of floors and devices that drain water into the riser, ending with the diameter of the pipes. Fan pipes are categorized according to their shape, diameter and the material used to make them. The diameter of the drain pipe depends on the diameter of the sewer riser. According to the material, they are divided into the following types:

1. Metal. Traditionally, the communication elements of the sewer system were made of cast iron. It is quite strong, durable and relatively inexpensive alloy. The disadvantages of this material are heavy weight and low ductility.
2. Plastic. Now, cast-iron fan pipes are gradually being replaced with plastic ones, since this material is much more plastic and easy to process. Plastic models are lighter, cheaper and much more practical than cast-iron ones, so they almost forced cast-iron ones out of the plumbing market.

Please note! When installing or replacing a fan pipe, it is possible to connect cast-iron sections with plastic ones, the main thing is to choose the diameter of the pipes correctly so that in no case will there be a decrease in the section in the system.

Requirements for a vented valve (aerator)

The installation of vented valves for sucking air into the system (Figure 5), which guarantees the normal operation of the sewer, is carried out on the basis of appropriate calculations.The throughput of the aerator must correspond to the design parameters of the throughput of the riser. In turn, the liquid flow through the riser depends on its diameter, type (ventilated / non-ventilated) and height. The calculations also take into account the diameter of the dictating floor outlet (with the highest flow rate), the angle of fluid entry through it, the height of the hydraulic seals and other initial data.

Figure 5. The principle of operation of the aerator - an air valve for sewage: 1. In the working position, the valve is closed - air from the sewer does not enter the room.2. When a vacuum occurs in the sewer riser, the aerator valve opens, the missing amount of air enters from the room, preventing the hydraulic seal from breaking.

In a simplified form, it is possible to coordinate the throughput parameters of the aerator and the ventilated riser using tabular selections. Initially, you should refer to Appendix "B" of SP 40-107-2003 for the installation of internal sewerage from polypropylene pipes. It is to him that SP 30.13330.2012 refers to determine the characteristics of the aerator.

Table 1. Capacity of a riser made of polypropylene pipes ∅110 mm equipped with a ventilation valve with an air flow area of ​​3170 mm2 and 1650 mm2.

Next, you should find out the sewerage consumption parameters with similar initial data. For ventilated risers, they can be gleaned from tables 6-9 (SP 30.13330.2012).

Table 2. Capacity of ventilated risers made of polyvinyl chloride (PVC) pipes (SP 30.13330.2012 (table 7)).

This also takes into account the diameter of the floor outlet and the angle of its connection. From the tables it becomes clear that, for example, for one of the most popular PVC pipes today Ø 110 mm with a branch Ø 110mm / 45 (bracket for connecting the toilet), the second throughput of the riser will be 5.85 l / s. This indicator turns out to be somewhat higher than with similar geometric parameters of the sewerage system with an air valve (5.44 l / s (Table 1)).

Functional features

With a sharp discharge of a large volume of water into a pipeline of small cross section, pipes often break, water hammer. Therefore, a sewer pipe for sewerage in a private house is an integral element of internal engineering networks. Due to its use, the sewerage system in a private house has an additional air flow, and additionally the design eliminates pressure drops.

An apartment building without a drain pipe can only function with the installation of a shower cabin, where the water flow is small. A standard bathroom refers to peak costs, during the discharge of effluents from a sanitary appliance, the pipe section is filled to the maximum, the flow of fresh air becomes minimal.

A similar situation in houses without a vent pipe provokes flooding of the first floors of the building at the time of massive water drain. Installing an additional structure will extend the life cycle of the sewer riser, especially plastic, and will also even out the work of home ventilation in the sewer pipes.

Many craftsmen advise narrowing the diameter of the pipeline, citing the lack of costs in the attic of the house.Regulatory documents, as well as experience in the operation of engineering networks in the private sector and apartment buildings, forces us to abandon such manipulations.

Sewer pipelines from the sanitary unit, where the toilet is installed, are dictating. The toilet drain pipe has a cross section of 110 mm, the household sewer riser must repeat its size or be larger. If two toilet bowls and two bathtubs are installed on the riser, it is necessary to carry out a hydraulic calculation of the throughput of the riser.

Appointment of a fan riser

Installing a fan sewer is the perfect way to solve this problem. We will talk about this in this article.

According to the current construction standards in low-rise buildings, it is allowed to install a sewer system without fan communication. But sometimes the installation of a fan sewer is still required in such houses. This is necessary in the case of the simultaneous use of a bathtub and a toilet bowl, when draining a large amount of water at a time, that is, when the volume of a one-time drain completely covers the cross section of the sewer riser.

The toilet bowl is installed on a pipe with a cross section of 110 mm, and the diameter of the drain hole of the tank is 70 mm. The combination of the bath with the sewer has a cross section of 50 mm. That is, when draining only the bath or only the toilet, the diameter of the sewer communication does not completely overlap. Plumbing fixtures and appliances (such as washing machine drains) generate small volumes of one-time runoff. Therefore, if the house has one toilet and a bathroom, a sewer pipe can be installed at the discretion of the owner.

A fan pipe is required in the following cases:

1. When the house has more than two residential levels (floors), and each of them has bathrooms;
2. When a pool or equipment is installed in the house that can drain a large one-time volume of runoff;
3. If a sewer riser with a cross section of 50 mm or less is installed;
4. If a septic tank is installed near the house.

General information

The mass of sewage that occurs during the flushing of wastewater into the system, entering the main, acts as a pump. Before the drain, the pressure indicator rises, and after them it decreases.

If the ventilation section of the line is not provided during use, a hydraulic seal breaks down. Air mass is sucked through the drain hole of plumbing fixtures. The effect contributes to the entry of gases into the building.

This problem happens with devices with a weak water seal. But sometimes a breakdown is possible in several areas at once. It is accompanied by characteristic gurgling sounds that appear in the drain holes.

If the line is equipped with a ventilation section, the air enters the line absolutely freely.

Due to this, the pressure indicator is stabilized. Breakdown of water seals does not occur. Accordingly, the smell of sewage does not penetrate into the room.

When to use a fan pipe

The fan structure can be installed in private and multi-apartment buildings, public buildings, if they have bathrooms. These are buildings with 2 or more floors. The product is not installed in one-story houses with one bathroom.

If in such a house there are several drain points, which in the aggregate block the riser or more than 2 bathrooms, a plastic fan pipe can be installed. Smells from the sewerage penetrate into the premises if the riser is with a small diameter (50-70 mm). This is possible if the kitchen has a separate external drain.In this case, you can safely install a fan design.

It is necessary if the septic tank is located at a distance of less than 8 m from the house and smells from the sewer penetrate into the living quarters or if the slope of the drainage system is insufficient.

In an apartment building or a multi-storey building for other purposes, if it has a sewerage system, the presence of such a structure is mandatory. Fan products can be installed in baths, pools and other similar premises.

What is a fan pipe used for?

According to the building codes in force today, the process of building a sewerage system for a one-story house can be carried out without a fan pipe. This is due to the small number of one-time drains.

If the building consists of two or more floors or the housing is equipped with several bathrooms, then a fan pipe is required in order to ensure stable pressure in the sewer system. This element connects the riser to the atmosphere, maintaining a stable atmospheric pressure even in the event of a volumetric release of water from the toilet tank, which provokes a vacuum in the outlet line.

According to accepted building codes, in a one-story building with one bathroom, there is a minimum amount of drains, so installing a vent pipe in the bathroom is optional.

If several toilet rooms are equipped in the living room, then the situation changes dramatically and a vent pipe installed on the toilet is a vital necessity.

This rule applies in the following cases:

• the house has 2 or more levels, which are equipped with a sewer system and water supply;
• cross-sectional diameter of the sewer riser - 50 mm;
• inside the building there is a pool or water equipment that drains a significant amount of wastewater into the sewer;
• The septic tank is close to the house, which can cause a rather unpleasant smell.

In the above cases, vacuum without a vent pipe can lead to the rapid emptying of the siphons under the toilet or sink, which will ensure direct contact of the "atmosphere" of the septic tank with the microclimate of the room.

Thus, the installation of a fan product in the sewer system ensures a stable pressure in the outlet pipeline and preserves the integrity of the water drains in the siphons under special drain holes that cut off the unpleasant aroma of septic tanks from the home microclimate.

The construction of a sewerage and ventilation system with fan pipes is rational in the following cases:

• when installing a sewer riser in a private house with a diameter of 50 mm;
• if the house has two or more floors, each of which has bathrooms;
• a private house is equipped with plumbing equipment, for example, a pool that generates powerful water flows;
• an autonomous sewerage system is located next to the residential building.

Toilets with direct (vertical) outlet to the floor are mounted using special spare parts. The sewer interchange is usually located under the floors, and the pipes do not require walls and partitions.

Plumbing installation with horizontal outlet

Connecting toilet models with a direct (horizontal to the floor) outlet is relevant for the conditions in our country. This is due to the fact that the bathroom is tied to a specific wall of the toilet room due to the specific wiring of sewer pipes in typical Russian houses.

Since the release in these models is directed back, it is located in the back of the product.The outlet pipe is attached to the pipe using a sealing cuff.

During installation, special attention should be paid to fixing the plumbing equipment to the floor of the bathroom. The legs of the bowl of sanitary ware with a horizontal outlet have specially made holes designed to securely fix the toilet bowl to the floor

Connecting plumbing fixtures with direct outlet ends with an installation process during which screws and dowels are used. Fastening must be carried out carefully, since in the case of a strong “pulling out” of the screw, the integrity of the surface of the sanitary ware can be damaged.

Installation of plumbing equipment with an oblique outlet

The process of installing and connecting plumbing equipment with an oblique outlet is carried out in stages:

1. Before connecting plumbing to the sewer system, the outlet of the device with grooves located inside should be lubricated with a mixture of red lead and drying oil (or sealant).
2. From above it is necessary to carefully wind the resin strand. The tip of the 0.5 cm long process must remain free, since the ends of the strand can fall into the hole and cause clogging.
3. The wrapped resin strand is lubricated with red lead.

Then the toilet bowl is installed, during which the outlet process is fixed in the socket of the sewer pipe.

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I’m willing to bet that even if you paid attention to the roofs of modern two or three-story cottages, you were only surprised at the abundance of pipes laid out, not even suspecting that there was a sewer pipe among them. And if its purpose is a mystery to you, then for sure you will want to know about its expediency, and in general - for what purposes it is intended.

Is it always necessary?

When building a drainage system for an individual house, the installation of a fan riser is not always mandatory. So, when building a one-story house equipped with a single bathroom, you can do without this element. But in the following cases, it will not be possible to do without a fan riser:

• the house has more than one floor, each floor has a bathroom;
• the sewer riser has a diameter of 50 mm;
• an object is connected to the sewerage system, the maintenance of which requires a large amount of water, for example, a pool;
• a sealed system is used with the installation of an underground septic tank.

When device installation is required

The sewer system has the most optimal structure so that the wastewater leaves, but the smell from the pipeline does not rise into the house

And an important part of such a product is a fan tube. It is discharged in the roof, connecting the sewer to the atmosphere.

However, many believe that this element is not necessary for private houses.

In what cases is it necessary to install a structure:

1. in multi-storey buildings. Moreover, a multi-storey house is considered to be a house that has more than two floors.
2. In houses where the sewer riser has a diameter of less than five centimeters.
3. If there are structures that occasionally release large volumes of water into the sewer. Such a device can be considered a swimming pool.
4. If an autonomous sewer system is installed near the house.

Thanks to the fan pipe, unpleasant odors will go out into the street

In these cases, the need to install a fan hood is not even disputed.Indeed, without it, the sewer simply will not function, and an unpleasant smell will be present in the house.

If there is only one bathroom in a one-story house, you can try to abandon the fan tube. However, the minimum risk of system discharge will still remain.

Do-it-yourself work

To organize a sewerage device in a house with your own hands, you need a scheme with which you can calculate what types of materials and plumbing will be needed and in what quantity. The drawing must be drawn to scale.

You also need to take into account factors such as:

• Soil type;
• Groundwater level;
• Volume of water use;
• Climatic features of the area.

Several types of laying sewer pipes are possible: under the floor, inside the walls, outside, but this is less aesthetically pleasing. Pipes laid in walls or under the floor are plastered 2 cm or filled with cement. To reduce the noise of the system, the pipes are wound without air gaps.

Scheme of the sewer system

The sewer system in a private house has a complicated scheme; it must take into account, in addition to depth and materials, the location, taking into account the requirements.

Namely:

1. To install a septic tank or other type of wastewater treatment, the lowest place on the site is selected.
2. The distance to the source of drinking water is at least 20 m.
3. To the roadway - at least 5 m.
4. To an open reservoir - at least 30 m.
5. To a residential building - at least 5 m.

Plastic pipes are well suited for arranging sewage

When drawing up a diagram, it is necessary to mark all the water drain points and the riser. The stand must be within easy reach. Usually it is installed in the toilet, because the toilet drain pipe has a diameter of 110 mm, like that of the riser.

Outflow pipes from the bathtub and sink are usually combined into one line.

It is important to remember that the toilet pipe should not have any inlets from other pipes. In addition, the diagram should include the location of the vent pipe.

Self-assembly

It is recommended to start installation in the house on your own from the inside of the sewer, as well as ventilation for it. The sewer system must contain hatches in the pipeline for inspection and repair. Pipes are fastened to the walls with clamps, hangers, etc. Crosses, tees and manifolds of large diameter (about 100 mm) must be used at the joints. Adapters will help to connect pipes of different diameters.

Ventilation is also important, which performs 2 functions at once - air inflow in rarefied areas, exhaust gases. Vacuum is more often formed when water is drained in the toilet bowl and when the pump for draining the washing machine is running. The influx of air prevents the capture of water in the siphon and the formation of a water seal, which has a loud unpleasant sound. A continuation of the riser on the roof is a fan pipe.

To install it correctly, you need to follow the rules:

1. The diameter of the fan pipe is 110 mm to prevent ice blocking the passage.
2. The height of the pipe on the roof is higher than the rest, including stoves, fireplaces, etc.
3. Location at a distance of 4 m from windows and balconies.
4. The fan pipe must be separate from the general ventilation and with a subsequent exit to the attic.

When arranging sewerage, safety regulations must be observed

Through a sleeve with a non-return valve, the collector in the foundation exits to the external sewer. The sleeve diameter is 150-160 mm.The reverse flow of wastewater in the presence of a check valve is not possible in the event of contamination of the pipeline or overflow of the wastewater receiver.

Paving depth

At what depth to lay the pipes depends on the deepening of the septic tank and the depth of soil freezing in the region. Moreover, pipes must be laid below this level.

They are laid according to the following scheme and rules:

1. Lack of turns from the house to the septic tank to prevent blockages.
2. Pipes of the correct diameter.
3. The same pipe material in the same pipeline.
4. Compliance with the slope (approximately 0.03 m per 1 linear).

If there is no slope or it has an insufficient degree, then you will need to install a sewer pump. Also, additional wells should be included in the external sewerage scheme, especially if there are pipeline turns from the house to the septic tank. They will help in the maintenance of sewers and the elimination of blockages or freezing.

Sewerage, like plumbing, is recommended to be supplemented with thermal insulation made of polyurethane foam and polyethylene or to lay an electric cable.

Fan pipe functions

Air is always present in any sewer pipeline, but when drained, it begins to escape into the atmosphere and draws water from the hydraulic seals. The absence of a water seal always causes a characteristic sewer smell to enter the room.

A fan pipe in a private house simultaneously serves three purposes:

• Gas withdrawal from the pipes of the sewer system;
• Maintaining the required pressure in the pipes, which allows you to simultaneously drain a large number of drains without the risk of introducing an unpleasant odor into the house;
• Forms the necessary vacuum in the sewer.

It is mandatory to install a fan pipe if the following conditions are met:

• The diameter of the sewer riser is less than 50 mm;
• Each floor has a separate bathroom connected to a single sewer system;
• Water from the connected pool is drained into the sewer;
• Right next to the building there is an autonomous sewer system (for example, a cleaning septic tank).