Any apartment building has a ventilation system. She is responsible for the influx of fresh air into the room and the removal of stagnant. But situations can occur when dirty air flows back inside the house. This phenomenon is called reverse thrust. It interferes with the comfortable life of people, and also carries a potential danger. You can correct the situation with your own hands when there is no malfunction of the system itself. In other cases, you need to contact a special service.
Back thrust determination
Under the draft in the ventilation system is understood the directional flow of air masses that occurs when the pressure difference in the house and on the street. Air flows naturally move into the low pressure area. By this principle, general ventilation works. First, the air is heated, its density and mass are reduced. It goes up and out into the ventilation hole. Fresh cold air comes through the cracks and fills the whole space.
The traction force directly depends on the height between the air inlet and outlet. For this reason, residents of the last floors more acutely feel a lack of fresh air.
The phenomenon of reverse draft in the ventilation of an apartment in an apartment building is the impossibility of removing dirty air. He returns to the rooms and brings bacteria and an unpleasant odor. You can understand that the system does not work correctly by the following signs:
- Window fogging, condensation, mold and mildew. Excessive humidity is also vented through ventilation. If the system does not work properly, water will not be discharged and will begin to settle.
- The stuffy stale air, often accompanied by an unpleasant odor.
- Draft from the vent. If you bring your hand to it, you can feel that it is blowing from the ventilation to the apartment.
The simplest test can be done with a plain sheet of paper. It must be applied to the ventilation hole and see the direction of oscillation.
Natural air circulation in the house
The ventilation system in the house is a complex of various technical devices, blowers and shafts, which have a single riser from the basement to the roof. Thanks to it, traction is created due to the temperature difference in the house and on the street. With this difference increasing, the hood will work harder.
The effect is exerted by perpendicular pressure on the principle of cross sections. This is a situation in which the wind blows horizontally with respect to the riser. As a result, it draws air from the ventilation.
So that the house has an influx of air and does not form a vacuum, vents are made in the foundation at the construction stage. You can also make several holes in the floor on the ground floor.
Thus, the natural air circulation in the apartment building works. The system may not work if there is no supply ventilation or when the temperature in the house is lower than on the street. The second reason arises infrequently, therefore, due to the lack of decent airflows, draft appears. The ventilation shafts in the apartment are made in the bathroom, toilet and kitchen. Air enters through the windows. The use of double-glazed windows and hermetic doors significantly reduces the inflow of air masses and causes reverse thrust. To solve this problem, use special valves on windows or walls.
Also, a violation of the air flow can be caused by a malfunction of the system, the installation of fans and hoods, incorrect design. If the hood is blowing in the opposite direction in the apartment, you need to look for the problem and fix it.
Reverse Traction Reasons
The main cause of reverse thrust is a violation of the principle of natural air exchange. It is caused by the following factors:
- The use of plastic windows and sealed doors. They are able to completely block access to fresh air in the room.
- Alteration of the ventilation duct or illegal demolition.
- Incorrect pipe design or selection of the wrong location. If it is installed in the zone of the wind shadow, circulation will be disturbed.
- Change the direction of the wind.
- Clogged ventilation duct with small debris, birds getting into it.
- Design errors.
To identify and eliminate backdraft, you should consult a specialist. It is better to choose independent experts who will conduct a comprehensive analysis of the entire air duct system in the building and give recommendations for improving the situation.
System check
A check is performed to identify and troubleshoot problems. It consists of the following steps:
- Study of design documentation. Checking its compliance with the norms and standards of GOST.
- Evaluation of the effectiveness of the installed equipment, the correctness of its installation and operation.
- Checking the quality of installation work of the duct, channels and other elements of house ventilation.
- Air sampling
- Search for unauthorized blocking of channels.
Based on the verification, experts decide how to reverse the draft.
Elimination methods
To remove the back draft, the ventilation system must be brought into working condition. The main ways to restore work that you can do yourself are:
- Install a check valve. The device will not allow old air to return to the room again.
- Installation of supply valves on the windows. Thanks to this mechanism, fresh air will enter the house, even if the window is closed. The intensity can be adjusted. Also in the valves you can install fans, trash screens and other nozzles for cleaning, heating and cooling the air masses.
- When installing a powerful hood, it is necessary to balance its performance. The volume of incoming air should be equal to the displaced.
If weather became the cause of the cravings, you need to wait until the normal temperature and humidity values are restored, as well as the wind direction. Such factors are temporary and do not depend on the person. With frequent influences of weather conditions, you need to think about redesigning the system.
If damage has occurred due to which the hood is blowing in the opposite direction in a private house, you must call the repair service. Specialists carry out the following activities:
- Protect the mouth of the shaft if traction is formed due to strong gusts of wind.
- Repair damaged structures, repair or replace them.
- They clean the channels. It must be carried out at regular intervals. Do not clean the ventilation yourself.
It is not always possible to correct factors affecting traction. For example, features of the layout of the room may be such that stagnant air will return to the room. In large rooms without walls and partitions, drafts will appear that affect the overall ventilation system in the house. Stagnant air masses can also return from the stairs to the second floor.
If the reason was the incorrect design of the ventilation duct, you should deal with its alteration.
Preventative measures
Eliminating the backdraft problem can take a lot of effort, time and money. To avoid this, preventive measures must be taken. Key tips:
- The system must be in good condition.
- Do not place fans or hoods in the ventilation ducts. You can use only recirculation hoods or take them out to the street through a wall or window.
- At the end of the riser, deflectors and rotational turbines are installed.
- Organization of the flow of fresh air from the street in any way possible, including in winter.
- Installation of interior doors to block the possibility of a draft, affecting the back draft.
- Winter cleaning of the system from ice and snow.
- Periodic ventilation check.
These measures will help to avoid most of the problems due to which a back draft is formed and cold air blows from the ventilation into the apartment.
Where to go
The ventilation of an apartment building is common. If there are problems, a reverse draft will appear in all apartments, so you need to act together. First of all, you need to discuss the problem with all the residents of the entrance. Perhaps in one apartment a very powerful exhaust hood was installed, which harms the operation of the entire system.
Next, you should contact the management company with a request to find and solve the problem. In case of cold stale air, you can contact gorgaz. This decision is due to the fact that ventilation is a security system. It is the presence of backdraft that does not make it possible to ventilate the room from energy sources and its combustion products.
If reverse thrust appears at a certain frequency in the house, and it is impossible to eliminate it, you should replace some of the windows with anti-explosion.
