The sewerage system of any private house needs ventilation. Proof of this is the "strange" sounds, gurgling and stench that penetrate plum trees in strong winds or hot summers. Investments in the arrangement of ventilation of the sewage system of an apartment building and a cottage, will preserve the comfort and pleasant atmosphere of the home, without too much ruining the budget.
Siphon and foreign odors
Some owners doubt whether ventilation is needed in the sewage system of a private house. And they are convinced of its necessity when the stench spreads from bathrooms and kitchens throughout the house.
The composition of sewage is heterogeneous, therefore, fermentation processes are constantly going on in the pipes, accompanied by gas formation. To prevent sewage odors from escaping from the ventilation, plumbing drain holes are equipped with a siphon (water seal).
With ideal sewage operation, the siphon is filled with water to a certain level. If the plumbing is not used for some time, the water level drops, organic vapors spread throughout the room.
Ventilation is needed to balance the pressure in the drain system.
Disgusting odors and gurgling are also explained by the fact that when the feces are flushed in the pipes, the pressure drops. The liquid from the full siphons is drawn into the pipes and nothing prevents the stench.
There is only one way to avoid the appearance of vacuum plugs - by a ventilation device for the sewer system.
Is the ventilation of the sewage system in a private house necessary?
Building codes allow the use of sewage systems without ventilation in houses no higher than 2 floors with a small amount of sewage.
If the volume of drains overlaps the cross-section of the sewer pipe, ventilation is required for the sewage system.
The drain will not close when one plumbing device is running in the house at the same time. For example, the standard diameter of the toilet bowl drain is 7 cm, and the pipe diameter is 11 cm. But if you drain two toilet bowls at the same time, the sewage system will close. For your information, the diameter of the drain pipe of the bathroom or washbasin is 5 cm.
Having calculated the possible salvo discharge of all plumbing fixtures at home, it becomes clear whether sewage ventilation is needed in a private house.
Ventilation in the sewage system is required if:
- the diameter of the risers is equal to or less than 5 cm;
- the house is two or more storey, bathrooms and washbasins are located on all floors;
- there is a pool or large bathtub in or near the cottage.
Another argument in favor of the ventilation scheme for the sewerage of a private house: modern siphons are often very small in volume and the water contained in them can dry out in a few days.
The owners returning after a short absence will be unpleasantly surprised by the unpleasant smell in the house.
The fan pipe in this case plays the role of a chimney. Due to the pressure difference, the air from the sewer is discharged into the street.
Fan pipe ventilation
The main thing in the ventilation device of the sewage system of a private house is the fan pipe. It removes "odorous" gases outside.
Usually, when designing a house, a channel for a fan pipe is provided.
Fan pipe location rules:
- The end of the fan pipe is brought out of the roof by at least half a meter;
- Distance to windows and balconies - at least 4 meters so as not to disturb the smell;
- It is forbidden to bring the fan pipe into the general ventilation of the house;
- It is possible to combine the sewer risers with one pipe for ventilation;
- It is not advisable to bring the ventilation riser under the eaves of the roof. There is a high probability of its breakage by snow sliding from the roof;
- The head of the pipe is covered with a ventilation hood for the sewage system. The ventilation hood equalizes the pressure in the sewage system, protects the system from rain and snow. Unlike deflectors, sewer hoods are resistant to icing during the cold season.
According to the rules, each sewer riser is ventilated separately. To do this, the fan pipe is mounted on the riser farthest from the place where the sewer exits the cottage. A septic tank will also be ventilated through it. Vacuum valves are installed at the ends of the remaining risers for ventilation of the sewage system.
Fan pipes for each riser make up the optimal ventilation scheme for the sewage system of a private house.
Materials and installation of sewer ventilation
Depending on the outputs, two ventilation schemes for the sewerage system of a private house are possible:
- Insulated or insulated;
- Uninsulated.
The first option is widely used in areas with harsh climates.
In private houses, PVC pipes are used for ventilation of the sewage system, which are inexpensive, tightly connected to each other, and are easy to install.
The cross-sectional diameter of the fan pipe should be selected more than or equal to the cross-section of the riser, from 5 cm in a 1-storey building and from 11 cm in 2 or more.
The diameter of the insulated riser at the outlet is about 16 cm.
Diameter of pipes for ventilation of the sewage system in an apartment building and a cottage for:
- liners for sinks or bidets 3 - 4.5 cm;
- kitchen sinks, showers, baths - 5 cm;
- toilets 11 cm;
- risers 6.5 - 7.5 cm.
Sewerage ventilation in apartment buildings, connecting 2 or more risers, is made of PVC pipes up to 20 cm in diameter. Pipes of even larger cross-sections are used to connect collectors and wells.
Vacuum ventilation valves
The valves are used as an alternative or supplement to the waste pipe. This is an exit if the house has already been built, but ventilation is provided.
Ventilation valves should not freeze up, they are usually installed in the attic. The mechanism of action of the ventilation valve for sewage is very simple. Its lumen is hermetically covered with a membrane held by a weak spring. When the water is drained, air is discharged in the riser, the membrane moves back and lets air into the sewer system. The pressure in the pipe is equalized and the valve closes automatically. Thus, the valve is open only when it is necessary to bring air from the room into the pipes.
Some owners prefer to install a vacuum valve for ventilation of the sewer directly in the bathroom or toilet. In this case, it is important to provide access to it for control.
The valve should be 30 - 35 cm higher than the floor.
The valve for ventilation of the sewage system can be assembled by yourself.
Materials and tools:
- spring from a fountain pen;
- end tee;
- self-tapping screw 45 mm;
- plastic lid for a glass jar;
- a small sheet of thin foam rubber;
- glue;
- awl.
Work progress:
- Cut out a circle with a diameter of 50 mm from the cover, screw a self-tapping screw into the center;
- Cut out a circle of slightly larger diameter from foam rubber and glue it to a plastic mug by pulling out a self-tapping screw;
- In the end tee, we make holes with a diameter of 5 mm at intervals of 25 mm, punch a hole with an awl and insert a self-tapping screw;
- Now we unscrew the self-tapping screw and assemble the finished valve.
If the valve is assembled correctly, the air blown into the holes will flow freely. The slot width is adjusted with a self-tapping screw.
Unfortunately, the vacuum valve can only partially replace a complete ventilation system.
After a while, it may become clogged or broken. And the valves are absolutely useless when the hydraulic locks dry out.
The waste pipe prevents the water trap from the siphons from being sucked into the pipes and very effectively prevents the odor from the sewage system. Ventilation reduces the stench and dryness of water traps, which are common in showers and drains.
Drain plumbing equipment must contain a water seal. Even with the proper ventilation of a private house, some of the unpleasant odors can penetrate through the drains without a water seal.
Ventilation piping to the sewerage system
Sometimes even a competent scheme does not provide high-quality ventilation of the sewage system in a private house. If the piping is too long (more than 3 m), increased ventilation is required.
To solve the problem, an increase in the cross section of the liner is required. So, the calculated indicator of 4 cm increases to 5 cm with a length of 3 meters.
If the liner is 5 meters, the diameter increases by 1/4. It will also be necessary to increase the cross-section of the liner with a height difference of 1 to 3 meters. An increase in diameter is also required when, when connecting to the toilet, the height difference is more than 100 cm.
If this method does not work, you will have to equip additional ventilation of the sewage system of a private house in the form of a vacuum valve or an additional drain pipe.
Video about whether the sewerage system of a private house needs ventilation and how it should be arranged:
