Sewer ventilation in a private house: schemes and design rules

Purpose of ventilation

It is widely believed that ventilation outlets in an autonomous sewer serve only to prevent an unpleasant odor from entering the house and living quarters.

This function is really available and is an important component. However, there is another important role of ventilation for sewers. It balances the pressure inside the pipeline

It balances the pressure inside the pipeline.

When draining wastewater in the pipeline, a rarefaction and air deficiency are formed. Then it starts going there automatically.If the ventilation is not working properly, air will not flow into the ventilation outlets, but through the drain holes.

Such operation of the pipeline can cause a disruption of the entire system. Therefore, the air must come from the ventilation outlets. The holes should be on the highest parts of the risers, the ends of which go to the roof.

But in an autonomous sewer system, stench elimination is also a very important function. This is especially necessary in the case of special cleaning septic tanks or autonomous stations, as well as in storage tanks. We will talk in more detail about what should be the ventilation of a cesspool in a private house.

About what should be the ventilation of the cesspool in a private house, let's talk in more detail.

When organic matter decomposes, not only an unpleasant odor is formed, but also a combustible gas, methane. With its large accumulation, if special ventilation ducts are not provided, poisoning and even a fire may occur.

Ventilation inside the house

Ventilation ducts must be installed inside the country house. Usually, a place for them is chosen at the upper end of the sewer riser.

Ventilation equipment for sewerage at the stage of laying the foundation of a private house

To ensure sufficient ventilation, the risers must exit above roof level. It is not even necessary that this pipe be vertical. It can also be bent. This outlet must not be connected to a chimney.

When bringing the pipe to the roof, the following rules must be observed:

• the upper end is carried out from the roof at least seventy centimeters;
• from the end of the branch to the nearest window must be at least four meters;
• the internal sections of the sewer risers and ventilation outlets must be the same.

Thanks to the device, when a vacuum forms in the sewer, air will be collected from the atmosphere. And the rest of the time it will be closed. The valve can be installed on any section of the sewer riser. However, it should be above all plumbing fixtures at home.

If necessary, the valve is even made by hand. For this:

• a spring is taken out of an ordinary handle, a self-tapping screw is selected under it, the length of which should be four and a half centimeters;
• a washer is made of plastic with a cross section of five centimeters from the outside;
• another puck is made of foam rubber with a cross section of six centimeters;
• holes are drilled on the lid for air flow;
• all components of the structure are assembled on the end cap so that the self-tapping screw is screwed in from the inside.

The device can be mounted on a tee by installing it on the highest section of the sewerage system. Then, when a vacuum occurs, the pressure from the outside will compress the spring and move the plastic-foam valve away.

Cesspools and their types

Central sewerage is, of course, the best of the systems that can be in a country house. However, for private country houses - this is far from always available. Therefore, you have to solve this issue yourself. A frequent solution is still the arrangement of a cesspool. To improve the quality of living, it is necessary to properly equip it.

Reservoirs for this are constructed in different ways. For example, use old tires. By type, cesspools are divided into:

• absorbent;
• sealed;
• septic tanks.

Whatever type is used, the pit is dug to a depth of no more than three meters, otherwise there is a risk of contamination of groundwater, which negatively affects the ecology of the site and the territory beyond it.

Sewer system testing

After completion of installation work, the sewage system should be tested. This is necessary in order to make sure that you did everything correctly. Be sure to check the joints and connections.

Testing the system is pretty easy. Open all faucets and leave for a while. After that, go through all the connections and make sure everything is dry. Or, paper can be placed under the piping nodes; if it gets wet, it will indicate leaks. If any, dry the identified areas, degrease and cover with new sealant. After drying, the test must be repeated.

Sewer ventilation schemes in a private house

Systems differ according to the type of arrangement and types of equipment. In addition to the fan pipe, vacuum valves are used, a ventilation circuit is laid to a septic tank, along an external wall or to a fence. Let's consider all types in more detail.

Fan pipe ventilation

If sewer ventilation is equipped with a fan pipe, then the network is called ventilated. The product is taken from the same material from which the riser is made. Most often, these are plastic products with a diameter of 110 mm to 150 mm. Sealing is provided with mounting sealant, plumbing paste. Light weight and easy installation is a plus. It is allowed to make a fan pipe from metal, polypropylene, ceramics.

Primary requirements:

• the cross section of the ventilation outlet must be equal to or less than the cross section of the riser;
• if the distance between the sewer risers is more than 4 meters, two fan pipes are mounted.

The advantages of the system are ease of installation and high-quality ventilation. The main thing is to bring the part above the horizon of the roof and securely protect it with a cap so that debris does not get in.

Ventilation with vacuum valves

Aerators or vacuum valves are installed when it is impossible to withdraw the fan pipe.

Products are available in different models, but they are the same in functionality:

1. Do not allow return air flows. There will never be a sewer smell in the house.
2. If a vacuum area forms in the riser, the valves open to receive a portion of air. The flow stabilizes the pressure in the system, reduces the risk of failure of hydraulic seals in siphons.

Structurally, the valve consists of a body, a flap, a seal and a spring mechanism. The principle of operation is not difficult - while the pressure in the network is normal, the valve is closed. The water drain acts like a piston - it pumps air into the septic tank, and a new portion of air enters through the hole in the pipeline. Thus, the pressure is normalized, the risk of failure is minimal.

Other ways to ventilate the sewer system

When deciding whether sewer ventilation is needed in a private house, the owner can choose other installation methods. All options are not prohibited by sanitary standards, they are equipped if it is impossible to use standard methods.

Consider three types of ventilation for sewers:

1. Along the fence. The construction is laid out only with the consent of the neighbors, they will not like the smell from the pipe.If the fence is far from home, laying a long pipeline is irrelevant - these are additional costs.
2. Along the outer wall of the house. It is used only if the outlet of the sewer to the roof for ventilation of the riser is not possible in the standard way. The design looks like a drain channel with a cap. Pros - ease of installation, high-quality ventilation. Cons - you need to carefully seal, joints and spoil the finish of the house.
3. Outlet to the septic tank. In this case, the riser crashes into the pipeline coming out of the septic tank. Difficulty in selecting the height of the part - too long a pipe is difficult to fix. Supports, trees are used as a support. It is believed that this option is the most successful, not requiring special financial and time costs.

In some systems, it is more convenient to introduce a ventilation riser, with the top cut placed in the attic. This is acceptable, provided that the attic is well ventilated. In this case, a trailer pipe is placed on the roof, the upper cut of the riser and the lower cut of the trailer are joined with a corrugation. And you can install the end pipe on the roof with an elastic adapter. Choose an adapter depending on the size and shape of the riser itself. If we take a step change in diameter, it is easier to fit the adapter to the pipe of the selected section.

When choosing a system, the user needs to decide whether ventilation is needed for sewerage or not. Even if the building has one toilet, a bathtub and a couple of sinks, the simultaneous draining of water can break the water seals and sewer odors will go into the house. Therefore, the ventilation system will be appropriate in any building. In addition, the design eliminates the threat of accumulation of gas plugs inside the circuits, increases the service life of the equipment.

Blockage Prevention

Periodic work to eliminate possible blockages of deposits is carried out by plumbers, in accordance with the maintenance schedule.

Only the slope of the route is not able to completely solve the problem of blockages (the installation of local treatment facilities is described in this article).

Preventive cleaning (read reviews on the use of the drug Dr. Robik) of highways is carried out for long sections of pipes and branches. On short runs, deposits do not have time to appear.

The procedure is carried out through the windows, at the points of connection of the plumbing fixture to the pipes.

The work is carried out with special equipment that can be bought or rented.

It is possible to lay pipes without slope to devices that use their own pump, such as a dishwasher or washing machine.

They also check the condition of the water seals for sewerage on each device in the apartment. The water plug creates an obstacle for unpleasant smells.

The curved shape of the siphons (which is needed to connect the dishwasher is written here) will allow solid sediment to accumulate, which is periodically removed. Do not forget that the portion of water in the shutter must constantly change.

INFORMATION. Modern apartments with a large area have two or more bathrooms.

Because of this, several risers can be mounted in the apartment, which are located at a distance from each other.

Design features

The street manhole is the following design:

1. Bottom. All inspection outlets must be of closed type;
2. Working part. It can be a wide ring, a curved geometric figure, less often a square or a rectangle.Here, if necessary, a specialist is immersed;
3. Lid, GOST 3634-99. A plastic or cast iron hatch for a manhole is an essential component. It protects the sewer from external pollution and guarantees the safety of households. It is recommended to supplement it with a lock.

Linear manhole design

Sometimes structures are equipped with a ladder, which allows you to move freely along the well. It is sometimes replaced with shelves. Their drawing is shown below.

Shelf layout example

The principle of the system is simple. The main pipe passes into the observation structure by connecting to the tank. The junction is carefully sealed. In any inspection outlet there is a tray part - the one in which the inspection is carried out, and the working one. Drains from the sewer pass through the working area, so it has a slight slope.

Building regulations

More than half of the inhabitants of Russia live in cities or urban-type settlements.

Living in a large settlement is associated with multi-apartment panel or brick houses.

High-rise buildings are connected to the city sewerage, have internal wiring for all apartments.

The correct functioning of the system is impossible without timely maintenance and compliance with the rules of operation.

Part of the housing stock was built during the Soviet period. The layout is carried out in such a way that the kitchen and bathroom are located nearby.

This allows you to use the general sewer wiring:

• waste collection begins in the kitchen (at what distance from the house a septic tank is installed, indicated here),
• passes through the toilet room and bathroom,
• included in the common stand.

The sewer system in apartment buildings is built on the gravity flow of wastewater under the influence of gravity.

Pipe products are laid under a slope (do-it-yourself step-by-step sewerage guide in the bath).

The angle is maintained evenly, otherwise, stagnation in turns is possible. The farther the plumbing fixture is from the riser, the higher the pipe should be.

IMPORTANT! When laying pipes, a slope of three centimeters is made for each linear meter of a pipe with a diameter of 50 millimeters. The sewerage system of a single apartment collects effluent from several plumbing fixtures (read about the fecal toilet pump on this page)

The sewerage of a single apartment collects drains from several plumbing fixtures (read about the fecal toilet pump on this page).

In this case, it is necessary to observe the angle of inclination of all branches. Qualitative calculation will create a margin of safety, prolong the operation of the engineering network.

The slope of the pipes is required. Increasing the angle will play a negative role in the passage of sewage (how to find out the volume of water in the pipe, read here).

Wastewater has a complex composition, which includes residues of fats, carbohydrates, and solid fractions.

Contaminants settle on the inner surface of the pipes and, accumulating, form blockages.

Jamming will not occur at the optimal speed of movement of drains, which is achieved by the correct angle of inclination of the line (see the sewerage scheme in a private house with your own hands).

Thus, self-cleaning of the internal volume of tubular products is achieved.

Requirements for the boiler room of a private house

The main requirements are described in SNiP 2.04.05–91.For systems with a power of less than 30 kW, it is allowed to install a gas model in the kitchen, but provided there is no stove. The exception is a closed type burner; oxygen in the kitchen is not used to create traction. If the power of the equipment exceeds 30 kW, a separate extension or building is equipped.

Requirements:

• The minimum area is from 15 m².
• Ceiling height - from 2.4 m. According to the standards, it is 6 m. If this figure is less, a correction factor of 0.25 is used for each meter lower.
• There are two types of air exchange - natural and forced.
• The window area is 300 cm² per 1 m³ of volume.
• Separate entrance. If this is an extension, it is allowed to make a door to the residential part.
• In the installation area of ​​heating equipment, the surface is protected with metal or asbestos board sheets.

If a model with an open burner is used, the length of the chimney is at least 4 m. The number of corner turns is up to 3 pcs. This is necessary to create traction.

Boiler room ventilation scheme

Channels for circulation are made at the construction stage. Their diameter is at least 20 cm. After the final calculation, smaller fans and grilles can be installed using adapter sleeves.

Location features

The pit should not be placed too close to the house

To prevent the unpleasant smell from disturbing the inhabitants of the house, it is necessary to pay attention to the fit of the collection hatch. Outdoor toilet must be attached without gaps

Ventilation in a pit latrine can be arranged by installing a regular PVC sewer pipe, ten centimeters in diameter. It is attached to the wall at the back.A hole is drilled on the floor for the pipe and lowered by about ten centimeters. The upper end extends beyond the roof by more than twenty centimeters. From below, the pipe must be insulated with tow moistened in advance with a bitumen primer. The exit is covered with a tin sheet, treated with foam or cemented.

When ventilation is installed in a cesspool without a toilet, installation is carried out in the same way. A pipe is inserted not far from the hatch, the length of which is calculated depending on the height of the outlet. If you attach an exhaust motor to the upper end, then the stench will not spread to the area, even in the summer heat.

By constructing a ventilation system in this way, it will be possible to avoid the accumulation of harmful gases and, as a result, the occurrence of an unpleasant odor in the toilet itself.

In addition, ventilation of the cesspool will prevent the harmful effects of fumes from feces on the wooden structure. Thanks to this, the term of the country toilet will increase markedly.

When building a pit latrine, it is best to make sure that the pit latrine is separate from the pit latrine. It is not difficult to connect them using a conventional sewer pipe with a large cross section. In this case, a branch for ventilation is connected to the pipe itself through a tee. Then excellent ventilation will be guaranteed, but on condition that a drain system is additionally provided for the toilet.

One way or another, the ventilation system here can be built in two ways:

• natural ventilation involves ventilation through increased pressure in the pit;
• with forced ventilation, air exchange will be carried out through fans that are powered by electricity.

Installation of natural ventilation

Above, we briefly mentioned the installation of natural ventilation of the toilet. Let's consider this process in more detail.

The air from the cesspool will be vented to the atmosphere through a vertical vent pipe installed on the back wall of the toilet. The outlet end at the top must extend beyond the roof.

Air will move due to the difference in pressure in the toilet and the atmosphere. Then the smell will not get into the room itself and the gases will be effectively removed to the outside.

The entrance of the sewer pipe must not be lower than the level of filling with sewage. Then it will never be closed by waste products.

To ensure sufficient air movement, the outlet section is made more than ten centimeters, and the upper end is raised more than seventy centimeters above the roof.

For a tighter fixation of the pipe to the toilet wall at the back, plastic clamps are sometimes used. Then you can be calm for her even during a strong wind.

In addition, the junction of the inlet pipe of the ventilation pipe and the cesspool must be carefully sealed.

Forced ventilation installation

The most effective method of ventilation is forced. It can only be implemented if there is an electrical supply on the site. But when used, you don’t have to worry: all gases from organic decay will be completely removed. The device is mounted as follows:

1. Even when the toilet is being built, you need to think about the location of the ventilation system and build a window for ventilation. It will be a source of illumination on the one hand, and an opening for air flow, on the other.
2. The toilet is supplied with electricity.A suspended structure for this will be the easiest way. When laying the power line, a cable is used that has special protection against external influences.
3. The fan is selected. In order for the air circulation here to occur normally, a model with a power of up to 300 watts will be sufficient.
4. It is best to first select a fan, and only then form the necessary hole under it. It only moves air in one direction. Usually this is air distillation to the outside.
5. To prevent vacuum from forming in the toilet, holes must be provided for air to enter. Their role may well be played by a gap located between the end of the door from below and the threshold.

Chimney Ventilation

Fan pipe indoors with a conclusion through overlappings

The fan pipe is used to connect the pipeline to the exhaust pipe (ventilation duct). Fan pipes are divided by shape and material. The choice of one or another product depends on the configuration of sewer communications and the place of their withdrawal from the building.

Principle of operation

If the drainage system is not equipped with a ventilation duct, then the sewage entering the sewer riser creates a "rarefaction" of the air. The lack of air is partially replaced by water in the siphons of sinks, bathtubs and other equipment.

With simultaneous draining, especially in multi-apartment and multi-storey private houses, a vacuum is created in the sewer pipe, which “breaks” the water seal. Therefore, unpleasant odors and harmful gases freely enter the room.

In sewer communications, where the installation of a fan pipe was carried out, the process is different.The air entering through the ventilation duct during the "discharge" in the riser protects the integrity of the water seal and normalizes the pressure inside the pipeline.

Mounting Tips

Accessories for assembling a ventilation pipe

When installing the exhaust pipe and sewage, it is recommended to use products from similar materials. This will allow for reliable sealing of joints due to the same fasteners and fittings. It is not recommended to use pipes made of various materials (plastic, cast iron), as the connection will not have sufficient strength.

Ideally, if design work has been carried out earlier and a place is provided for the installation of an exhaust pipe. Before starting work, it is advisable to prepare all the necessary materials and tools.

If installation work is carried out in old houses where a sewer system based on cast-iron pipes already exists, then you will need to purchase a fan pipeline from a similar material. When using plastic products, the existing system is completely dismantled and new communications are laid.

Exhaust pipe outlet through interfloor ceilings and roof

When installing ventilation on the basis of fan pipes on your own, you should follow certain rules:

• According to the project, the end of the exhaust fan pipe is led to the roof of the house through interfloor and attic floors. The height above the roof level is at least 50 cm. When passing through the attic, the height from the ceiling to the end of the vent pipe is at least 300 cm.
• When the exhaust pipe is led through the ceiling, the interface is insulated with sound-absorbing material. If necessary, a steel box is mounted, the space inside of which is filled with heat-insulating material.
• When constructing ventilation for sewerage at an already operated facility, the outlet of the vent pipe is carried out through the bearing wall. Laying through the floors is undesirable, as this can lead to a decrease in their strength.
• The cross section of the exhaust pipe must be equal to the cross section of the riser pipe. As a rule, in multi-storey private houses, a pipe with a cross section of 110 mm is selected.
• If there are several risers, they can be connected to one exhaust pipe at the top. The connection of sewer ventilation with a stove chimney and an exhaust hood is not allowed.
• The length of the pipe from the plumbing equipment to the exhaust pipe should not exceed 6 m. The connection is made by connecting the siphon of the equipment to the socket adapter.
• For laying and exiting the pipe, special couplings and bends with the desired angle of rotation are used. The connection of various elements of the exhaust pipe is carried out using crimping metal clamps, seals and silicone-based sealant.

If during the process of output through the roof the fan pipe hits the floor beams, then a bend with the required angle of rotation (30–45) is installed for displacement. In multi-storey private houses, it is recommended to install an element with a plug (revision) on each floor. If blockages occur, this will quickly eliminate the problem without dismantling the ventilation duct.

Features of types of sewerage

Sewer ventilation consists of special details.

1. Air valve - its action is aimed at passing air into the riser and blocking any incoming gases from it inside the house.Private small houses are rarely equipped with a septic tank, so sometimes they use aeration valves installed at the top of the riser. A similar option involves installing a ventilation pipe on a septic tank. Unfortunately, valves are not able to replace siphons, because they are aimed only at supplementing.
2. A fan pipe is a ventilation channel that connects to a sewer riser and leads to the roof. The pipe can not only rid the room of an unpleasant smell, but also equalize atmospheric pressure, remove harmful gases. Odors can only appear if the siphons dry out.
3. A water seal is a mandatory attribute that is built into the sewer system. Its presence provides a high-quality removal of unpleasant odors.

A water seal is a mandatory attribute that is built into the sewer system

• non-isolated system;
• insulated.

In the first case, the type of sewer system is only 110 millimeters, while the insulated one reaches 160 millimeters. The height of both options is the same - 500 millimeters. Regions with a harsh climate mainly use an insulated system, inside it there is a special non-freezing condensate.

The sewer does not need a special deflector that increases the exhaust capacity, however, due to the warm air escaping to the outside, there is a very small risk of condensation forming, which will close the ventilation outlets. Ventilation of the sewer riser is a necessary measure for a comfortable stay and the prevention of negative aspects.

In the sewers of private houses, there are often accumulations of various harmful gases formed during the decomposition of organic matter.Every time you use the toilet, the sewage pressure changes. A water seal will not be able to save a person from the penetration of gases that affect human health. In private homes, this problem is solved by a home ventilation system.

Features of the functioning of sewer ventilation

Scheme of internal and external sewer ventilation 

The sewerage of a private house consists of two parts - internal and external. They work together to form an efficient drainage system. However, organic waste decomposes in the pipes, producing methane and other foul-smelling gases. All this is accompanied by the release of heat. Heated fumes quickly spread along the highway and, at the slightest opportunity, seep into the premises. Therefore, often in private houses, residents face specific problems associated with sewerage - an unpleasant smell appears in the rooms and the gurgling of water is heard. Emissions from cesspools are especially dangerous, which can cause fires and explosions. In such situations, a quite reasonable question arises: is sewer ventilation necessary?

To avoid such troubles, there must be an exhaust hood in the sewer that connects the main cavity with the outside air. Heated vapors move along it and are discharged into the atmosphere, and fresh air descends in their place. The pressure in the pipes equalizes, reduces the noise that appears during the use of plumbing. This ensures a constant level of water in the siphons, which does not let gases into the room.

In the photo, the ventilation of the sewer system

Sewer ventilation operates at any time of the year - in the heat and in the cold.This is due to the difference in the temperatures of the gases in the pipeline and the air outside the house, due to which mutual heat exchange occurs between them. A pressure difference is formed, which contributes to the effective ventilation of the line.

The classical ventilation system is created for natural ventilation of the highway. It is considered intra-house, tk. installed in the building. The design consists of the following elements:

• fan pipe. It is installed on the sewer riser and is displayed on the roof. The detail connects the system to the atmosphere.
• Air valve. Designed to pass air in only one direction - into the pipe. It is installed in the riser and in its branches. If the house has a septic tank, the valve is mounted on top of the ventilation riser connected to it. With its help, the pressure in the system is equalized when a large amount of water is released.
• Deflector. Accelerates the flow of gases removed from the sewer. Attached to the top of the piping.
• Cap. Set if there is no deflector.
• Water seal (siphon). Mounted directly under the sink, sink, behind the toilet and next to other plumbing fixtures to prevent the penetration of gases into the room. It is always filled with water. If the siphons fail to work, an unpleasant smell appears in the room. For example, with a sharp discharge of water in the riser, a vacuum is formed, which draws the liquid out of the hydraulic seal. As a result, a channel is formed through which gases escape.

In some cases, it is allowed to create sewer ventilation systems in an apartment that differ from the classic ones. These include:

• Ventilation without a pipe. Instead of an exhaust hood, an air valve is mounted, but it does a worse job.
• Forced ventilation. In such systems, electrical devices of various designs are installed that blow gases out of the line. For these purposes, low-power axial superchargers are used - 200-350 W. They are of several types: field, in the form of an impeller mounted on the motor shaft and placed in a housing in the form of a snail; axial, which are installed inside the pipe. Fans are used in sewer systems that are rarely used. In them, the water in the siphons quickly dries up, and they cease to fulfill their function.