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Should the sewage system "breathe"? We figure out why the sewer pipe is brought to the roof

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

What it is

Of course, the website is not an encyclopedia, and you will probably want me to support my story with links to the regulatory documents that govern its purpose. And this is quite understandable, because today construction marketers "sell" so many unnecessary products and additional elements to ignorant buyers that a natural question arises: is not this pipe for the sewerage from among them? Maybe you can do without it?

No, you can't do it. This is a really important and necessary element of the sewer system of any high-rise building. If in essence, then the sewer drain pipe is not intended for the movement of water. Its purpose is to connect the sewerage system to the surrounding atmosphere.

There are several reasons for this:

1. You know from a school physics course that thrust arises in any vertical pipe. With an increase in pressure in its upper part, through leaking joints, air penetrates into the living quarters, and, as you understand, it smells like not flowers;

A water seal is not a panacea, since there are vulnerabilities in the sewage system in the form of connections of a sewer comb (intra-apartment sewage system) and a siphon elbow, the tightness of which is far from ideal.

1. Mass discharge of water, which is not uncommon in high-rise buildings, leads to filling of the riser, as a result of which an air front with excess pressure is formed in front of the water flow. This phenomenon is neutralized with the help of an audit of the basement sewage system (if it is a private house, then excess air comes out through the sewer pipe of the septic tank);
2. At the same time, a vacuum is formed behind the downward mass of wastewater, the force of which is sufficient to suck out the water seals (from the toilet bowl, from the knee under the bathtub and sink). The leftovers are unable to hold the air, and the rooms are filled with unpleasant odors.

Captain Evidence suggests: to solve the described problems, and both at the same time, is possible with the help of a bridge between the atmosphere and the sewer system.
With a salvo discharge of water, odors will go through the sewer pipe riser, and the water locks will remain intact.

Regulations

SNiP 2.04.01-85

This condition is realized through the risers, in which the exhaust part must exit through the roof or through the ventilation shaft.

The height of the riser depends on the type of roof and is indicated in the table:

The permissible distance from the exhaust part of the riser to the balcony or the nearest window is 4 meters.
Why the instruction requires it is hardly necessary to explain.

SP 40-107-2003

Another set of requirements under the number SP 40-107-2003 stipulates the case of the outlet of the fan pipe on the operated roof. In particular, in clause 4.8 it is said that the exhaust part of the riser must be equal to 3 meters. But at the same time, it is permissible to combine four or more risers within the technical floor.

It is worth noting that such a system operates quite well.
But the slightest non-tightness of any joint will lead to the fact that the owners of apartments on the upper floors will inhale "aromas", since there is no escape from the draft created in the risers.
The narrowing at the top contributes to the creation of excess pressure in them.

Installation highlights

The fan pipes still need to be correctly mounted:

1. Understating the diameter of the exhaust pipe is highly undesirable.... Diameter transitions from 110 to 50 mm reduce the throughput by 5 times. And it is quite expected that it will simply not be enough to compensate for the pressure drop;

1. The horizontal part of the sewage system should have a slope of 2 cm per linear meter... Its presence prevents the formation of air and water jams;
2. The withdrawal of sewer risers that open into the attic will not lead to anything good... And not only because of odors, high humidity will quickly saturate the thermal insulation with dampness, which in turn will lead to rotting of the truss system (wooden or metal trusses);
3. When the fan riser is brought to the roof, it should be equipped with a deflector, thanks to which neither debris nor precipitation will get into the pipe. Of the advantages of the deflector, we also note the increase in traction in windy weather, which increases the efficiency of the entire system.

If, after reading the regulatory requirements, you are still full of doubts as to whether you need ventilation of the sewer system or not, we offer simplified explanations:

• If you are designing a house, then be aware that the district architect will not approve your project without funded allotments if the future building has more than 2 floors;
• If the number of storeys is 1-2 floors, then the number of toilets and bathrooms matters. Fan output is not needed if there are only 1 of them.

But that's not all - even if your project provides for only 2 floors with one bathroom and one bathroom, then their location will play a role:

• A fan pipe is needed if the toilet is also located at different levels;
• A roof outlet is needed if a pipe with a diameter of less than 100 mm will be used for laying the sewer;
• The connection of the sewer to the atmosphere is required if there is a pool in the house;

• The presence of sealed treatment facilities will also require the arrangement of a fan pipe.

Unforeseen moments

Let's return to the apartment buildings, where a negative trend has been observed in recent years - during the repair of the sewerage system, residents of the upper floors unknowingly (or perhaps deliberately) dismantle the sewer riser leading to the technical floor.

If you ask about the reason for such "innovation", then most of the answers will be typical - "who needs it?" But this intervention does not go unpunished - after a couple of weeks, a stable and unpleasant smell appears in all apartments upstream of this sewer riser.

In such a situation, the best solution would be to install a sewer fan valve instead of the remote section of the system. This device is constructively a "block-post" - letting in air only inside the pipe, and not letting it out into the room.

Let's simulate a situation in which the residents have installed a drain valve:

• In normal operation, due to the resulting thrust, excess pressure is formed in the upper part of the riser. It prevents humid and unpleasant odor-filled air from the sewer from entering the room;
• The vacuum arising during a salvo discharge of sewage periods activates a valve through which air is sucked into the system, and the pressure will equalize.

The vacuum valve I am describing is not 100% odor-proof.
This can only be achieved by completely sealing all joints.

Author's remarks

Let me add some useful and practical advice to the typical recommendations as personal experience:

1. My own house with 2 toilets and 2 baths, located on different floors, was built without a fan outlet. And at the same time, there were no smells inside the room, since the simultaneous use of two or more spillway points is a rather rare event;

1. In the house of our friends, similar to my home, we designed and installed a fan outlet. At the same time, we were guided by the requirements of SNiP 2.04.01-85, in the part that describes the dominant direction of the winds. It is not worth increasing the exhaust part of the riser by more than 4 meters, since it can freeze in winter;

The likelihood that the pipe will be heated by the warm air rising from the house decreases with every extra centimeter of its length.
A couple of days of cold weather - and an ice plug will necessarily form inside, and with it smells will appear in an apartment or house.

1. We did not lead the fan outlet through the roof, but mounted it with our own hands through the pediment. A definite plus is a minimum of work with roofing material and subsequent sealing.

Conclusion

I hope that in this publication I was able not only to replenish your construction glossary, but also to professionally explain how the sewage system functions in your home. And if you are a resident of the upper floors, then warn you about the possible consequences of unauthorized interference in its work.

As always, the video in this article will allow you to explore additional related content. Please feel free to post your additions and comments. Good luck, comrades!

Autonomous sewerage of private houses is a rather complex structure that must meet all established standards. Otherwise, it will work ineffectively or you will have to carry out frequent restoration work. An example is a situation where a vacuum is created in a pipe. Consider the features of installing a funnel sewage system in a private house in more detail.

1. When draining wastewater through a vertical pipe, a rarefaction process takes place, which can be partially compensated by the remaining wastewater in the siphons. In such cases, there are no problems with the operation of the sewer system.
2. With a one-time salvo discharge, a sewer vacuum is created. This problem is quite widespread in the event that a fan riser is not installed.
3. The sewage system eliminates the possibility of a vacuum, in which the smell and the drains themselves can get back into the room.
4. In the presence of an outlet to the atmosphere, the formed vapors and gases are naturally transported upward. As a result, vapors and gases do not enter the branch pipes located at an angle, that is, the problem is solved.

It should be borne in mind that building codes determine that there is no need to install a background riser due to a small one-time discharge of effluents. A vacuum arises when the drains fill the entire section for a sufficiently long section, which is possible only when choosing a small diameter pipe or with a large one-time discharge from several sources back.

In general, we can say that the system under consideration is technically simple. The pipe, represented by a riser, also performs the function of a branch. The main thing is to comply with all the requirements for creating this system.

Fan pipe design

To begin with, let's pay attention to the cases in which it is necessary to create a funded sewage system:

1. In the case when a riser or a large section of a sewer pipe has a diameter of less than 0.5 cm. Even for a house that has only a few sources of wastewater, such a cross section is rather small.
2. When using an autonomous closed-type sewage system, for example, septic tanks, into which oxygen is not pumped. If the drains are discharged into half-open type wells, then the system is partially discharged. The septic tanks are built in such a way that they are completely isolated from the outside world. In this way, the likelihood that an unpleasant odor spread throughout the territory is excluded.
3. In the case of a high probability of a volley discharge of a huge amount of water. If the house has several bathrooms and showers, swimming pools, artificial reservoirs, as well as a large number of equipment that uses water in their work, then a fan exhaust of vapors and gases should be provided, since the volley discharge will be significant.

When designing a waste pipe, the following points are taken into account:

1. The diameter of the drain pipe and the sewer pipe must match exactly. Only in this case, it is possible to ensure effective discharge of the sewer system to eliminate the likelihood of a vacuum.
2. The location of the drain pipe in relation to windows and balconies should also be taken into account, since unpleasant air will enter the room.
3. The waste pipe must be located strictly vertically, otherwise its efficiency drops significantly. Therefore, when creating a project, this point should be taken into account.
4. In the event that the house has an attic floor, it is necessary to provide for the location of the drainage demand near the walls and other communication elements. That is why, when building a private house, his project is already created with a background sewer system.
5. All information is applied to the design drawings of the structure, which avoids problems.

When choosing a pipe type, attention should be paid to the following points:

1. To solve the problem, the PVC version is also suitable. Such pipes have a lot of advantages, among which we note the low cost and weight. The lungs are easier to fasten and require no maintenance. Modern autonomous sewer systems are often created precisely when using PVC versions.
2. Cast iron pipes, which have recently enjoyed low popularity, can also be installed. There are quite a few disadvantages: high cost, heavy weight, difficulties during installation work, and so on.
3. More recently, ceramic pipes were used to create the sewage system, but today they are extremely rare. The reasons are high cost and fragility.

The above information determines that it is quite important to timely carry out the creation of the project and implement it.

Requirements for the fan riser

Considering the requirements for the fan riser, you should understand the principle of the system. A bad smell can come from pipes or an installed septic tank. The resulting vapors have a specific gravity less than atmospheric, as a result of which they rise up the system.

A large number of requirements are not imposed on the fan riser:

1. He must be straightforward. Vapors rise naturally. This moment determines the lack of traction. Therefore, only straight sections of the system should be installed.
2. When creating a riser, a pipe of the same diameter must be used. Otherwise, the thrust generated will not be enough. Different adapters should not be used as this will significantly reduce traction.
3. When placing the riser, it should be borne in mind that an unpleasant odor will come out of the pipe and be carried by the wind around the area. It will be almost impossible to avoid this, so the location of other living quarters should be taken into account.

The requirements depend on the complexity of the system and many other points.

Fan tube alternative

It is possible to solve the problem under consideration associated with the appearance of an unpleasant odor in the house from the sewer system by installing:

1. Sewer check valve. This design can prevent wastewater from moving in the opposite direction. The locking mechanism can also be used to eliminate the possibility of bad odors entering the room.
2. Locks in siphons. This mechanism is installed in the areas where the branch pipes exit to the riser. They are represented by various valves that can be closed manually.

However, the system under consideration does not have high efficiency in the case of a salvo discharge of sewage when a vacuum is created.

Installation of the fan pipe and outlet to the roof

The above information indicates that the fan pipe may be needed quite often. You can carry out its installation with your own hands if you have available material at hand.

1. First you need to deal with the existing sewer system. The first step is to replace old pipes, which are best replaced with plastic ones. Over time, cast iron products become less and less popular, since they are not practical to use, the surface has a high roughness, which causes severe blockages. Dismantling work can be done quite quickly and simply: the pipeline is disconnected from the riser, after which the disassembly is carried out in stages. Significant problems can arise with old cast iron pipes.
2. It is recommended to install the drain pipes from the lowest stiffness point. As a rule, it is located in the main riser. If work is carried out in a country house, then installation is recommended to start from the place where the foundation starts. The work is represented by the creation of holes in the supporting structures, after which the pipe is installed and temporarily secured with clamps. After installing all the plumbing, a funnel outlet is brought to the source of wastewater, for example, the toilet bowl.
3. If difficulties arise when creating a flexible drainage pipe, when the pipes do not fit into each other, you can use soap or silicone. O-rings are lubricated with these substances. Do not use heavy loads as PVC pipes and O-rings may be damaged.
4. When installing the waste pipe, it is recommended to use only metal clamps. This type of fastening is the most reliable. The studs on the standard clamp, which are made of metal, have a screw structure. This moment allows you to precisely adjust the characteristics of the connection.
5. Installation work should also provide for the insulation of the structure. Particular attention is paid to the zone of contact between the pipe and other elements of the structure. Of course, PVC does not react to environmental influences, but nevertheless, care should be taken to protect the elements of the sewage system. Despite the large number of advantages of PVC pipes, there is also a significant drawback, which is poor insulating qualities. Due to the small wall thickness, the sound of falling waste water can spread throughout the room. This problem can be avoided by foam insulation of effluent or vapor outlets. You can also use rolls of mineral wool.

If it is necessary to carry out repair work, we will pay attention to the following points:

1. As previously noted, the drain pipe must be the same diameter as the riser or larger.
2. The end of the exit must not be folded or narrowed. However, special hoods can be installed to prevent rainwater and snow from entering the system.
3. It is recommended to lay most of the pipe in a warm room, and only the ends in a cold area. In order to create additional thrust, the required pressure drop is created due to a sharp change in temperature. In any case, part of the pipe will be located in the cold part of the room.
4. The number of risers in the house determines the number of drain pipes. Therefore, when designing an autonomous sewage system, a significant increase in the number of risers in the room should be avoided.

At the design stage, quite a lot of attention should be paid to the funnel pipes and their locations. Often, the design of a house is related to how many exits there will be, since they will be located on the roof or attic floor.

In conclusion, we note that when carrying out work on the installation of a fan riser, it is necessary to replace the elements of an existing system. This is due to the partial execution of installation work.

A healthy microclimate in a home is made up of several factors. It would be a mistake to think that it depends only on the presence or absence of an air conditioner and a properly installed ventilation system. The most important component of the fresh atmosphere of the home is a well-assembled fan pipe. She successfully copes with odors coming from the sewer. The presence and normal functioning of the structure guarantees the absence in the house of the "aroma" of impurities and loud unpleasant sounds when the water is drained.

How the funnel works

This device is designed to provide ventilation of the drainage system. It connects the structure of sewer pipes to the atmosphere or to a specially made ventilation duct. The shape and length of the device can be arbitrary. You can find straight, bent at an angle, vertical and horizontal parts.

When arranging the sewer system, most often the installation of a fan pipe is performed - a ventilated riser. The operation of the device prevents the smell of impurities from entering the apartment

The principle of the funnel pipe is quite simple. Waste water discharged into a vertical riser creates a vacuum in the pipeline. It can be partially compensated by the water in the siphons of the plumbing fixtures. But with a powerful drain or a high height of the riser, the vacuum formed in the sewer pipe, with a characteristic "chomping" sound, breaks off the water locks of the equipment, draining the siphons. In this case, there are no obstacles to the smell from the sewer.

In systems equipped with a funnel, things are a little different. The vacuum created in the sewer pipeline does not have time to "suck" water from the siphons. This is prevented by atmospheric air, which begins to be sucked into the system simultaneously with the appearance of a vacuum in it. Thus, the water locks in the plumbing equipment remain in place and successfully prevent the penetration of unpleasant sewer odors into the apartment.

When is ventilation necessary?

According to the norms, the sewer pipe must be installed in the following cases:

• The building has more than two residential floors, each of which is equipped with a sewerage and water supply system.
• A one-story building is equipped with a pool or has other devices that can produce one-time drains of a significant volume.
• Sewer risers in the building have a diameter of 50 mm.

Low-rise buildings are usually erected without ventilation. However, it should be borne in mind that this is advisable only for small one-time flows. Determining their level is fairly easy. Installation of the device will be considered necessary if the wastewater flow can completely block the vertical riser.

The most common situation: the toilet is most often installed on a pipe with a diameter of 110 mm, the hole of the cistern has a cross-section of 70 mm and a pipeline with a diameter of 50 mm leaves the bath.

In multi-storey buildings, where water supply and sewerage are supplied to each apartment, the installation of a fan pipe is necessary. The riser is displayed on the roof

It becomes clear that the simultaneous operation of one bathtub and one toilet will not create problems. Even if a dishwasher or a washing machine and a sink are connected to the sewer, they will not be able to seriously increase the volume of a one-time drain. Therefore, ventilation in this case is installed at will. But if several bathrooms and toilets are planned in the house, it becomes impossible to do without equipment.

Ventilation must be installed not only in engineering systems, but throughout the house. How to do it correctly, you will learn from our article:.

Features of the installation

The installation of such a riser can be carried out independently. First of all, for this you will need to purchase suitable pipes. You need to understand that the structure is a direct continuation of the sewer pipeline, so the pipes from which the main system is assembled are quite suitable for it.

Make sure that the section of the element to be installed coincides with the sewer hole or is slightly larger. Practice shows that the optimal diameter of the funnel is 110 mm.

To ensure the differential pressure and temperature necessary to create a draft, it is recommended to choose a place in a heated room for the initial section of the riser. The final section, on the other hand, must be located in the cold. This should be an open place, then the thrust created in the pipe will freely remove unpleasant odors into the atmosphere. The actual installation of the device is extremely simple: the installation of the structure is carried out in a pre-prepared ventilation duct.

There are two practically equivalent options for the competent arrangement of the fan pipe: the outlet of the ventilation riser to the roof and the installation of a check valve

Check valve system

The equipment put in place can be equipped with a special system called. It allows for normal operation without bringing out the ventilation riser to the roof. In addition, the device is required for:

• Correction of insufficient slope of the sewer pipe.
• Prevention of ingress of mechanical impurities and rodents into the system.
• Obstacles to returning wastewater to plumbing fixtures.

The check valve on the drain pipe should be installed without the use of all kinds of greases and silicone. The surface must be clean and dry

Depending on the type of check valve, it can be installed outside or inside the element. The device is directed towards the movement of drains, its elements, made in the form of petals, must be bent towards the plumbing fixture. Internal installation involves thorough cleaning and subsequent degreasing of the inner surface of the pipe, where the insert will subsequently be installed. Experts strongly do not recommend using various lubricants during installation, including silicone ones, designed specifically for sewage. All installation work is carried out only on dry surfaces.

Sewer ventilation riser

Traditionally, the upper part of the funnel is brought out to the roof in the form of a ventilation riser. According to the recommendations of construction SNiPs, the height of the structure should be at least 0.5 m on a pitched roof, 0.3 m on a flat unexploited surface and 3 m on an exploited roof. At the same time, the minimum horizontal distance from the riser to the openable balconies or windows should be at least 4 m. It is strictly forbidden to combine the outlet of the fan pipe with stove chimneys or ventilation.

If there are several sewer risers in the house at once, they can be connected with one exhaust part. In this case, the section of the pipe selected for its arrangement should be equal to or greater than the diameter of the risers themselves. For most buildings, the diameter of a single exhaust section will be 110 mm. The combined exhaust elements are laid with a slight slope, of the order of 0.02%, directed towards the direction of gas movement.

Taking the device to the attic is strongly discouraged. It is also prohibited to install the outlet of the fan pipe directly under the eaves of the roof, since the snow falling and sliding from the roof can easily damage it. All kinds of additional designs for the hood, such as weather vane or deflectors installed at the outlet of the sewer riser, will not give the expected effect. On the contrary, according to experts, they provoke the appearance of condensation in the system, which is fraught with blocking of the outlet openings if it freezes.

You will also find useful material on which pipes to choose to make sewer ventilation, and what factors need to be taken into account when designing:

The functioning of the sewerage system without ventilation is possible. But will the owner of the home, where such a system is installed, agree to the constant smell of sewage? Competent installation of a funky design will easily solve an unpleasant problem, especially since you can do it yourself. After carefully reading the instructions, you can safely get down to business. As a result, the house will not only shine with cleanliness, but also smell of it.

To connect the sewer system with the atmosphere and ensure its ventilation during the construction of communications in residential buildings and public buildings, a sewer pipe is used for the sewage system.

Sewage water, flowing down a vertical riser, creates a vacuum in the pipes, which is partially compensated by residual water in the siphons. However, if there is a one-time powerful drain, the drains, when moving down, form a vacuum in the sewage system and cause the emptying of all siphons. This, in turn, leads to the penetration of unpleasant odors from the bowels of the sewer into the room.

This problem is quite real and it causes a lot of inconvenience and discomfort. The installation of a fan pipe will help to solve it, you can learn about which from our article.

The use of funnel pipes

In accordance with the current building regulations, the construction of a sewer system without including a fan pipe in the design is possible if a one-story house is being built. This is due to the small number of one-time drains.

However, even in low-rise houses, the need to install a fan pipe sometimes arises. This happens in cases of a single discharge of a large volume, when the cross-section of the vertical riser is 100% blocked by the wastewater flow, for example, when a bathtub and a toilet are used at the same time.

As a rule, the toilet bowl is mounted on a sewer pipe with a diameter of 110 mm, the section of the flush hole of the cistern is usually 70 mm. A pipe with a diameter of 50 mm is supplied to the bathroom, which is then connected to the riser. Thus, the section of the siphon does not exceed 110 mm. It turns out that when one toilet bowl or only a bathtub is in operation, the inner diameter of the riser does not completely overlap.

Sinks, washbasins and household appliances connected to the sewerage system (dishwasher or washing machine, etc.) are also not able to significantly affect the volume of a one-time drain, therefore, in this case, a toilet pipe can be installed at will.

If the house has several bathrooms that are used by different family members at the same time, the installation of a funnel is mandatory.

The construction of a sewer system with drain pipes is advisable in the following cases:

1. installation in a private house of a sewer riser with a diameter of 50 mm or less;
2. the presence of two or more floors, each of which has sanitary facilities;
3. if the house has a pool and other plumbing equipment that generates powerful drains.

Installation

Installation of funnel pipes

If you are installing a fan pipe with your own hands, follow the basic rules:

1. when purchasing building materials, make sure that the cross-sections of the sewer riser and the fan pipe coincide; the optimal diameter of the fan pipe (as well as the riser) is 110 mm;
2. the outer section of the riser should be placed in such a place that the sewer "aromas" from it quickly and easily disperse in the atmosphere;
3. the starting point of the sewage system should be located in a heated room, but the final point, on the contrary, in a cold one. This provides the necessary temperature and pressure drop, due to which the removal of unpleasant odors outside the house is carried out.

Pro tip: The waste pipe is an actual continuation of the main sewer riser and can be made independently from a pipe intended for sewage of the corresponding diameter.

Unpleasant odors in the bathrooms appear due to the fact that the siphons of insufficient volume are installed on the sanitary appliances. In small siphons, the residual water quickly dries out (in 3-5 days if the plumbing is not used), which opens up free access to odors from the sewage system inside the room. Sometimes the installation of siphons of larger capacity is impractical, then the replacement of the fan pipes in the apartment is required.

If the sewage system of a residential building has such a component as plastic waste pipes, the problem is solved as follows:

• the air in the sewer riser, rising up and falling outside the pipes, creates a vacuum in the sewer system;
• when siphons are dehydrated, air from the room seeps into the sewer, and not vice versa;
• the air remains fresh, without an unpleasant odor, even with prolonged non-use of plumbing.

Outlet of the ventilation pipe to the roof

The tasks of the domestic domestic sewage system include the transportation of wastewater from the building to the external sewer system. For its efficient operation, good ventilation is needed, which is provided by risers equipped with drain pipes.

Pro tip: The vertical fan riser should be led out to the roof. It is strictly forbidden to place the output in the attic.

To properly install the fan pipe, you must adhere to the following principles:

1. ensuring the outlet of the funnel pipe to the roof, the optimal height is provided - 50 cm; if the roof is used for any purpose and is actively exploited, the outlet of the riser should not be less than 3 m;
2. a sewer pipe, 110 mm in diameter, is connected to a sewer riser of equal cross-section;
3. several risers can be connected with one fan pipe;
4. it is forbidden to organize the outlet of a riser equipped with a fan pipe, together with a ventilation system or stove chimneys;
5. the outlet of the fan pipe, located above the roof, is made at a distance of 4 m or more in the horizontal direction from the openable windows, balconies, etc.

Connection of several risers with one fan pipe: 1 - oblique tee; 2 - knee 45 degrees; 3 - straight knee; 4 - straight tee.

The sewer riser, brought out to the roof, does not need to install any additional exhaust devices (for example, a deflector, a weather vane). Moreover, the use of these devices can lead to the release of condensate in the system, which, when frozen, will block the outlet openings.

For ventilation of the sewer system, sewer pipes are used: the sizes of such products vary, but the most common use of 110 mm pipes.

Check valve for waste pipe

The installation of the fan pipe is simple: the installation is carried out in a channel provided in advance in the ventilation. If the ventilation circuit contains a small number of ventilated risers, the waste pipe can be discharged horizontally through the nearest wall. This, moreover, will not harm the interior design of the room.

Waste pipes must be equipped with a non-return valve. It corrects the situation when the wrong slope of the sewer pipe is made, and also protects the sewage system of the house from:

• return drains back to plumbing fixtures;
• penetration of rodents;
• ingress of mechanical impurities.

The valve can be installed not only inside the drain pipe, but also outside. Internal installation involves preliminary thorough cleaning and degreasing of the pipe with further installation of a special insert. The waste pipe check valve is sold separately from this insert. It is placed in the opposite direction of the flow of drains, and its petals should bend towards the plumbing.

When laying a drain pipe with a working diameter of 110 mm, an adapter is required to install the check valve. If there is a connection of the funnel pipes with gray pipes with a sawed-off socket, the valve is mounted in the pipe.

Pro tip: When installing a check valve, experts do not advise using silicone and any other lubricants, even those intended for sewage systems. Perform all installation operations on dry surfaces.

A sewer fan or ventilation pipe is a necessary attribute of any sewage disposal system, both in a multi-storey building and in a private cottage. What is a fan pipe for? The installation of such a pipe simultaneously solves two problems. Firstly, gases are removed from the pipeline network through ventilation. Secondly, ventilation is needed to maintain constant pressure in the pipe system, since at the time of the descent of a large volume of water in the sewage system, air depression occurs.

What is a fan pipe? It is customary to call a fan pipe a pipe that connects the sewer riser to the atmosphere. The presence of such a pipe prevents the occurrence of a vacuum in the system, which, in turn, does not allow disrupting the operation of the water seals.

In the absence of a drain pipe, at the time of the release of a large amount of water, in all devices located above it can break the water locks. And through empty siphons, an unpleasant smell of sewage will begin to flow into the premises.

The need to use waste pipes

According to building regulations, a sewage system without a drain pipe can be built in a one-story house. This tolerance is based on the fact that in small houses a large volume of wastewater cannot form at the same time.

However, a sewer pipe in a private house will not be superfluous even in a low-rise building. Installation of a pipe is necessary if, while draining a large volume of water, the cross-section of the riser pipe is completely blocked.

In most cases, the size of the hole in the cistern is 70 mm, and the drain from the toilet is carried out using a pipe having a diameter of 110 mm. The outlet from the bath is assembled from pipes with a cross section of up to 50 mm. Thus, when using only one piece of plumbing, complete filling of the riser cannot occur.

Small diameter sewer pipes are attached to the rest of the plumbing fixtures. Therefore, their use has no significant effect on the total volume of simultaneous discharge. Therefore, in one-story houses, the installation of a fan pipe is optional.

Advice! As a rule, the largest amount of wastewater is formed when the water is drained from the toilet and bathtub at the same time.

Another thing is a house of two floors and above. Of course, we are talking about those cases when bathrooms are located on each of the floors. In this case, several people can use the plumbing at the same time.

And with the simultaneous drainage of water from two toilets, the riser section will be completely closed, therefore, in such houses, the installation of fan pipes is mandatory. In high-rise buildings, the normal functioning of the sewerage system without a drain pipe is impossible, since in such a house a large number of people can use the sewerage system at the same time.

Consequently, the probability that the entire section of the riser will be occupied by drains increases many times. Thus, it is imperative to include waste pipes in the system if:

• For the construction of the riser, a pipe with a cross section of less than 110 mm was used.
• The house has several bathrooms and it is possible that they will be used simultaneously.
• If there is a device in the house that is capable of providing a significant amount of drains at once. Such devices include, for example, a swimming pool.
• The house is equipped with local sewerage and the sewage treatment plant is located a short distance from the house. In this case, ventilation from the sewer pipes helps prevent the smell of gases from the decomposition of organic matter in the septic tank from entering the premises of the house.

Installation and repair of waste pipes

The sewer pipe can be made of either plastic or cast iron:

• Metal pipes. This is a traditional solution, since 50 years ago, domestic sewage systems were assembled exclusively from cast iron. The material is durable, but it is very inconvenient to work with, since it has a significant weight.

• Plastic. It is the most popular material for sewer assembly. Many owners change their old cast-iron sewage system for plastic, and when building new houses, this material is the most in demand. Plastic pipes are lighter, more cost effective and more aesthetically pleasing. Therefore, today cast iron pipes are used much less frequently.

Advice! When installing or replacing the fan pipe, if necessary, you can join parts made of cast iron and plastic. The main thing is that the diameters of these elements match. The narrowing of the diameter in the funnel must not be allowed, otherwise it will not fully function.

In addition, there are conditions that must be observed regardless of what material the pipes are made of:

• The diameter of the waste pipe must be equal to (or greater) the diameter of the sewer riser. Building codes prohibit the use of a pipe of a smaller section.
• The funnel is usually led out to the roof. It should not be installed near windows and balconies. The minimum distance from the surface of the roof ridge is 30 cm.

Installation rules for funnel pipes

When installing a funnel pipe, you must strictly adhere to the recommendations enshrined in SNiP.

• When purchasing material, you need to make sure that the diameter of the drain pipe is not less than the diameter of the riser.

Advice! In private construction, most often, for the construction of risers and, accordingly, fan pipes, a plastic pipe with a cross section of 110 mm is used.

• The starting point of the sewer system must be in a heated room. But its end point, on the contrary, should be located in a cold place. This will provide the required temperature and pressure difference and allow the ventilation to efficiently evacuate gases.

• The ventilation pipe of the sewer is actually a continuation of the riser, therefore it is made of the same material as the riser itself.

Advice! Sometimes the constant presence of an unpleasant smell of sewage in rooms is due to the fact that siphons of insufficient volume are installed under the plumbing fixtures. If you do not use the devices for several days, then the water plug will simply dry out and unpleasant smelling gases will penetrate into the rooms. Installing a funnel will help solve this problem as well. The air in the home will stay fresh even if the plumbing is idle without being used.

Ventilation outlet to the roof

Fan pipe installation rules:

• The outlet of the ventilation pipe to the roof should be organized at a height of at least 30 cm, and preferably 50 cm from the ridge. However, if the roof is an exploitable object (for example, there is a summer terrace on it), then the height of the outlet can reach three meters.

• If several risers are installed in the house, then they can be equipped with one fan pipe.
• The horizontal distance from the windows and balconies of the building to the outlet of the fan pipe should be more than 4 meters.

When constructing ventilation of the sewage system, it is strictly prohibited:

• Lead the drain pipe to the attic, not to the roof.
• Organize the outlet of the fan pipe together with the outlet of the chimney and the ventilation duct.
• Lead the fan pipe under the roof overhang, because in winter, when snow and ice come off the roof, the pipe can be damaged.

Some homeowners, in an effort to improve the ventilation of the sewer, are trying to install additional exhaust devices on the pipe. Such as deflectors, weather vane, etc.

In fact, such devices not only do not give the desired effect, but can also contribute to the accumulation of condensate in the system. And in the cold season, moisture can freeze and block the path of movement of air and gases.

Check valve installation

It is imperative to install a non-return valve on the waste pipe. They put the valve on the sewer drain pipe immediately after installing the toilet. Valve working principle:

• When water is drained from the drain tank, the valve cover opens, allowing drains to flow through.
• In the absence of fluid from the house, the valve cover is tightly closed. Moreover, it has such a design that it is impossible to open it from the reverse side.

That is, installing a valve helps to avoid such an unpleasant situation when drains from an external pipeline (for example, as a result of a blockage) penetrate into the house, flooding the premises with dirty water.

So, the waste pipe is an element of the sewer system, which is used to ventilate the pipeline and maintain normal pressure in the system. The installation of the waste pipe must be carried out in accordance with the requirements of building codes.