Fan pipe (48 photos): what is it, installation diagram for sewage in a private house, fittings for options with a diameter of 110 mm

Sewer pipelines are well known to modern people. But it is not only the wastewater and solid particles themselves that need to be discharged outside - various odors are no less a nuisance, which the drain pipe helps to fight.


The waste pipe is a piece of the sewage system that connects the riser that removes the sewage with the atmosphere. Thanks to this design, the danger of waste water is reduced, the accumulation of bad "odors" is excluded. Only in one-story buildings is the absence of such a technical unit allowed. But when there are at least two floors, or there is more than one sanitary unit in the house, you cannot do without it, otherwise the large-scale release of water from the tank and the rarefaction it provokes in the outlet will provoke a deterioration in the atmosphere in the house.

The current regulations prescribe installing a fan pipe in the following cases:

  • in houses with more than one level equipped with water supply and sewerage;
  • in the event that the cross-section of the risers is 5 cm or more;
  • if the house is equipped with a swimming pool or other reservoir that discharges a significant amount of wastewater;
  • in the event that the septic tank is located next to the home.


For sewerage, you can use fan pipes made of cast iron or plastic. Cast iron is compatible exclusively with cast iron, while plastic is much more versatile, so plastic is recommended when repairing and replacing broken parts. Metal products are currently rarely used also because they are not flexible enough and their range is too scarce. Most often, installation is carried out into a sewer line with a diameter of 110 mm.

Professionals believe that funnel lines made of dissimilar materials are not very strong. Ideally, all sewer parts should be selected from one substance. If such a solution is not possible, then it is worth consulting with qualified engineers how this or that combination of materials used will behave. The fan pipe can have almost any geometry - it is permissible to lead it vertically or horizontally. There are even individual options that are mounted at an angle.

It should be noted that the funnel highway should be larger in cross-section than the main highway. Therefore, the choice of relatively light and highly durable plastic gets an additional advantage over the use of a cast iron odor discharge line.

The exit from any fan system is by all means located outside the border of a residential building, otherwise no effort will help to cope with the emerging harmful odors.

When installing both cast iron and plastic pipelines, the same products are used as for the waste channels:

  • fitting;
  • pipes;
  • bends;
  • rubber cuffs;
  • transition blocks;
  • clamps (with their help, the line is attached to walls and other surfaces).


The waste pipe in a private house is formed by individual outlets to drain points and risers. If the dwelling is quite large, and the bathrooms and toilet rooms are remote from each other, then a scheme with several fan risers is needed - this will help to avoid placing long horizontal sections of the pipeline with their inevitably weakened traction. If several branches are connected into a single circuit, then it is recommended to mount the pipe with a slight slope. It should be understood that placing the initial site in a warm room, and the final one outside, is extremely useful for intensive air exchange.

The faster the air flows through such a channel, the better the fresh atmosphere in the dwelling is maintained. Since the key part of the funnel pipes is placed vertically, you need to carefully approach the fastening of the structures. The connection is achieved with metal clamps. Some experts consider it necessary to install soundproofing pipes with mineral wool rolls and slab structures.

Much attention should be paid to the exit of the fan structure to the roof of a one-story or multi-story building.

Standard requirements stipulate that it is not allowed to bring sewer structures into the attic. If you mount the outlet under an overhang, then as a result of falling snow or ice down, an expensive structure may be damaged. The height of the funnel structures above the pitched roof should be at least 50 cm, and if it is flat and not in use, then this indicator should be at least 0.3 m.Most often, several pipes lead to the roof at once - among them, the air exhaust pipe will be the highest. It is strictly forbidden to form a single circuit of the fan and ventilation system, as well as to connect to chimney structures.

It is forbidden to bring the fan pipe closer to the windows than 400 cm. The optimal output is considered to be in the area where the largest number of drain structures is concentrated. Transferring it, for aesthetic reasons, is fundamentally unacceptable. It is also forbidden to supplement the funnel pipes both inside the house and outside with any decorations - each such element can provoke the formation of condensation and ice, reduce the effectiveness of odor care.

It is recommended to install a non-return valve, which increases the efficiency of the system and prevents the return of contaminated gases and the formation of contamination on the walls.

There is no need to contact a specialist except in some particularly difficult cases. However, it is required to strictly follow the recommendations and instructions of the standards. The complexity of the construction of funnel systems using modern materials is small.


The diameter of the drain hole in the tanks is 7 cm. As for the drain pipes themselves, there are no particularly stringent requirements. In an apartment building, they should be the same size as the main riser of the sewer main.

In private housing, it is quite justified to use two times smaller output sizes, since air will move along them. Therefore, fan ducts with a cross section of 50 mm are often installed there. The outlet from the toilet bowl and the main sewer pipe are made the same - 100 mm each.

It is these dimensions that turn out to be the most rational in a private house. But there are also deviations, especially if the generated load is small and a simultaneous significant flow of water is unlikely. If a pulling or supplying ventilation is equipped, then it is worth focusing on diameters from 50 to 110 mm (most often 90) with a length of 300-400 cm. Pipelines with a height of 150 cm are in demand. Such values ​​have not just developed within the framework of everyday practice - they are regulated by SNiP.

It is important to know that the required rise of 30 cm is determined not from the floor plane, but from the surface of the roof covering. A distance of 4 m should be maintained in relation to both windows and balconies.

Returning to the dimensions of the fan pipes themselves, it is worth noting that the diameter of 150 and 200 mm is typical for industrial versions of this device. At home, however, pipes with a diameter of 7.5 cm are occasionally mounted.This approach is necessary if larger options, for geometric reasons, do not fit in a particular plumbing unit.


Choosing the ideal device and determining its parameters is only half the battle. Quality installation of equipment is equally important. The conclusion to the roof presents serious difficulties - installation work inside the house is no more difficult than manipulating other plumbing fixtures. But it is quite possible to get around this problem if you start from the recommendations given by professionals. For example, they warn against using fungi.

The rise of warm air through the drain pipe can lead to freezing of condensate on this element and blocking its lumen. In this case, the thrust will inevitably decrease. The closer the outlet is to the ridge, the more reliable the created system and the less likely that the snow mass will tear off the roof. In those buildings that differ in three or more floors with long sewer wiring, it is advisable to install two air ventilation risers. But here there is a rule: the risers are made straight, like arrows, since the slightest turn or bend will drastically reduce their efficiency.

The maximum result is achieved if the liner is connected to the outlet with corrugated adapters. When there is one outlet for several risers, the total diameter of the external discharge channel should be equal to the diameter of the riser. The auxiliary ventilation duct should be connected to the sewer version below the outermost of the plumbing devices or from above to the upwardly directed branch of the curved tee. But first, you should make sure that this branch is located above the instrument panels and inspection hatches, because sometimes, even with a fan pipe, extraneous odors arise.

The reasons for this circumstance may be associated with the following problems:

  • wear and tear of the cuff that connects the toilet;
  • broken connection of sewer pipes;
  • problems in the hydraulic seal.

Only after checking and refuting all these assumptions or eliminating such defects, but not having achieved a positive result, is it worth replacing the fun construction. It is advisable not to rely on your own knowledge and skills, but to entrust the matter to trained specialists.

If, nevertheless, it is decided to do the work on its own, then it should be understood that sometimes even the toilet cistern has to be dismantled. It is especially difficult to work with cast iron channels, which cause a lot of inconvenience even for specialists.

It is impossible to disconnect the fan pipe in an apartment building. The only option is to agree with the neighbors so that they do not turn on the washing machines and turn on the water taps for some time. Toilets are also not recommended for this time. The dismantling itself is carried out using a sledgehammer and angle grinder. Subsequent installation is always carried out from the lowest point, and in private houses it coincides with the base of the foundation.

It is possible to simplify the connection of pipe parts to each other by lubricating the sealing rings with silicone. But even if this reagent is not available, the problem is easily solved: you need to use a simple liquid soap. It is worth considering that the silicone bond is stronger than the soap bond, but it will complicate the dismantling. If it is necessary to connect cast iron and plastic pipes to each other, special adapters should be used, which can be purchased at any plumbing store. Fastening to the wall is made with metal clamps, which are much more reliable than plastic counterparts and more convenient to use.

Old funnel pipes, installed several decades ago, were fixed only on the floor and on the ceiling. Such a solution is today recognized as impractical, because the connection of all sections of the circuit is considered much more effective. After the completion of work with fasteners, sewer pipes are attached to the risers - for this purpose, bends or tees are used. Then comes the turn of connecting the sewer circuit with plumbing equipment.

It is very expensive to use sewer pipelines equipped with acoustic protection. Most people will find it much more profitable to mount the necessary protection on their own. When working, use polyurethane foam or mineral-based plates. The disadvantage of the foam version is the need for any revision to cut it off and re-add it. Hiding risers in a soundproof box looks very aesthetically pleasing, but a control window must be provided.

The fan pipe itself does not have a slope, since it must be installed strictly vertically. As for the slope of the sewer pipelines to which the ventilation circuit is connected, it should be 1-4 cm per 1 running meter. A lower value will slow down the flow rate of all effluents. Exceeding the permissible steepness will lead to the fact that the liquid will begin to leave faster than solids and inclusions.

When installing the drain pipe, it is necessary to pay attention to such an important detail as the cross - this is a type of fittings that receive a stream of unpleasant gases.

Additionally, a tee is mounted into which the toilet pipe is built. The number of large tees should correspond to the number of discharge points. The only exception is that there is no need to install such an element in the bathroom.


The outlet of the sewer pipes is directed in such a way that the accumulations of sewage gases are removed by the wind. It is unacceptable to place the output in those places where they will concentrate and stagnate, even if no one visits these places. If, for some reason, it is not possible to bring the sewer pipe to the ventilation system, then the outlet from the fan circuit can be led out through the wall.

Decorative rosettes are a great help to cope with the negative aesthetic effects of such a solution. To bundle several funnel pipes, tees designed for angles of 45 or 135 degrees are used.

If there are horizontal sections in the system, then their slope along the gas path should be at least 0.02%. In those places where it is required to change the direction of the pipes, this can only be done over the last connected devices. For such a change, only pipes with an angle of 135 degrees are allowed.

In the case when the attic of the house is used, it is necessary to increase the height of the outlet to 3 m. All fan risers passing through unheated rooms must have a thermal protection layer.

Plastic pipes must be led out through the ceilings using metal sleeves. Above it is worth mounting a cover and a net - they will protect small insects from entering the funnel system. Instead of a drain pipe, an air valve can sometimes be used, installed above the revision part of the riser. But this solution is applicable only in houses where there is no more than one sanitary unit. Vacuum valves, regardless of their quality, quickly become clogged and cease to perform their basic functions.

The problem with valves also arises when the siphon (hydraulic seal) is deprived of water. In this situation, the entire system becomes useless. In addition, the hydraulic valve, even in ideal mode, is not able to 100% protect against unpleasant odors - it is imperative to supplement it with supply and exhaust ventilation ducts. Only a full-fledged fan system is able to provide good air in houses with toilets, bathrooms, washing machines and dishwashers.

Fan pipes are mainly made of PVC. But it is much better to choose multilayer structures based on polypropylene, since they are distinguished by an increased level of sound insulation due to the presence of special additives. The increased wall thickness and optimal design at the corners also help them to dampen extraneous sounds. In order not to be mistaken with the selected dimensions of the drain pipes, it is recommended to carry out thorough engineering calculations of the entire system.

It is advisable to make a minimum of turns, and if you resort to them, then only at an angle of 45 degrees. The connection is made mechanically: socket. Any docking unit must be equipped with a rubber seal that makes the riser airtight. It is advisable to choose clamps with vibration-damping gaskets and install them in increments of 700 mm. In houses made of natural or artificial stone, as well as when using reinforced concrete floors, pipes must be passed through them using non-combustible cases.

Adequate protection against fire and mechanical damage is guaranteed by cutting steel pipes. In most cases, such cases are mounted directly when arranging the floor. Key cut-off factors are house settlement and pipe heat deformation from the inside. The sleeve should exceed the fan pipe by about 10 mm in diameter.

It is recommended to fill the resulting gap with a soft, impermeable material that allows the pipe to move along the longitudinal axis.

Most often, such materials are:

  • polyurethane foam;
  • oiled rope;
  • a rope soaked in bitumen;
  • silicone based sealant.

To output the fan system through the roof, it is allowed to use a special pass-through device. It is made both universal and adapted for a specific roofing material. Sometimes the drain pipe is pulled inside the chimney with a corresponding increase in its cross section.

It is forbidden to extend supply ventilation in the same place.

Replacement of funnel pipes with valves of the same purpose should be performed only after consulting with professionals.

It should also be borne in mind that if there is a septic tank in the house, then you will need to openly remove ventilation. Installation of valves in unheated rooms, where the accumulation of condensate can completely block their operation, is inadmissible. It is very important to buy component parts exclusively from well-known manufacturers - the products of anonymous and little-known companies are rarely of high quality, and shortcomings are discovered only in a critical situation. It will not be possible to find differences in appearance - even the consultation of a specialist when buying does not always help.

See the next video for more details.