How to check ventilation in an apartment: rules for checking ventilation ducts

Alexey Dedyulin
Checked by a specialist: Alexey Dedyulin
Author: Irina Zhirova
Last update: March 2019

In urban environments, people spend most of their time indoors. Lack of fresh air threatens to reduce performance, worsening well-being.

And if you add to this the constant presence of extraneous odors, mustiness, dampness, mold in the corners? Knowing how to check the ventilation in the apartment, you will not take the situation to extremes.

We have described in detail all proven practical methods for checking the effectiveness of ventilation systems. Here you will find useful information about the device and options for improving ventilation. The information is supplemented by visual illustrations and video guides.

Check draft in ventilation outlets

Let's cut several strips of thin paper 20 cm long, 2-3 cm wide and hold them alternately to the ventilation vents in the apartment 5-7 cm apart.With normal ventilation, the ends of the strips should touch the edge of the vent, but not be drawn into it.

Suppose a paper strip is drawn to the outlet just barely, does not deviate at all or deviates in the opposite direction. Ventilation is definitely bad, but you need to find out what the matter is - whether clogged ventilation ductswhether there is no air flow.

Open the door and window, repeat the experiment with a piece of paper. If this time the strip was pulled into the outlet - the ventilation shaft is in order, otherwise you must look for the cause of its malfunction.

The same can be checked with a flame of a match, a lighter or a candle, cigarette smoke, but this is highly discouraged. The probability of gas leakage and its accumulation in the ventilation shaft is small, but a piece of wall broken through to the neighbors is the minimum of those serious consequences that can occur in this case.

Manually checking ventilation draft
In order to avoid ignition and explosion of combustible substances accidentally accumulated in the ventilation system, do not use open fire to check the ventilation draft, and do not endanger your own and others' lives

Ventilation is not only checked by the “yes / no” criterion, but also the air velocity in the ventilation duct is measured with an anemometer.

The sequence of actions is as follows:

  • we fix the readings of the device;
  • the measurement result and the size of the ventilation grill in diameter are entered in the formula below;
  • we get how much air the ventilation system lets through (cubic meters / hour).

The formula for calculating:

Q = V * S * 3600

  • Q is the volume of air per cubic meter. m / hour;
  • V - air flow rate in m / s (measured by anemometer);
  • S - cross-sectional area of ​​the ventilation hole in m2 (we measure with a tape measure).

The standard for a kitchen with an electric stove is 60 cubic meters. m / h, for the bathroom - 25 cubic meters. m / hour. Measurements should be made with a temperature spread of at least 13-15ºС (for example, outside + 7ºС, and in an apartment + 21ºС). Outdoor temperature should not exceed + 5-7ºС.

When warming, ventilation becomes worse, the check will be unreliable. The stronger the outside air warms up, the greater the measurement error.

Empirical Table
The values ​​of the average air velocity supplied by a duct of a certain diameter are obtained empirically

If the thermometer in the apartment shows a plus, and on the street at this moment it is minus, the internal air rushes from the room up through the ventilation duct, because it is lighter and warmer. But with temperature equalization, the draft in the channel weakens. When in an apartment, for example, + 22ºС, and outside the windows - + 32ºС, less heated internal air remains below and does not go into the ventilation duct.

Minimum air consumption per person
The volume of regularly updated air needed to perform work and rest in the premises is regulated by the collection of SNiP 41-01-2003

On hot summer days, even completely prosperous natural ventilation stops coping or switches to work in the opposite direction. But this is not a reason to consider it faulty.

In our apartment buildings, the supply and exhaust ventilation of the gravitational principle of operation is arranged.It works according to the laws of physics, air masses spontaneously enter the premises and are pulled out through the exhaust duct.

Measuring traction in the ventilation system
For domestic use, it’s enough to buy a simple model of the anemometer, and professionals use more accurate devices with remote recorders and built-in calculation options

Ways and features ventilation devices meticulously disassembled in one of the popular articles on our site.

The reasons for the lack of air flow

So, checking the draft showed that the ventilation ducts are free, and the air in the apartment stagnates, the kitchen stench and, even worse, the toilet scent do not disappear.

The thing is that the ventilation of most of our apartments was originally designed to receive fresh air naturally through old wooden window and door structures due to the loose fit of the shutters, the presence of cracks.

Natural ventilation in the apartment
Natural ventilation in the apartment: 1- air enters the room from the street, 2- flows from room to room, 3- goes into the ventilation duct. The performance of such a ventilation system depends on the season and weather.

And now completely different building materials with high density, various heaters, sealants, and also plastic windows are used. We strive to make our homes warm with protection from noise and cold penetration from outside, and as a result, we block the flow of air.

Plastic windows and metal entrance doors clog the room so that it turns into a sealed one.

Air does not pass, draft in ventilating vents is absent. It is especially bad in winter, when the windows do not open even for ventilation, so as not to chill out the rooms. But the problem is easy to solve.

It is enough to slightly open the window, and air will begin to flow into the formed gap. He will go around the apartment and reach the ventilation openings, which are usually located in the kitchen and bathroom.

Unfortunately, in winter, if we air our housing, it’s different. We open wide all the windows at once, but for a short time. At the same time, the air is completely renewed, the apartment does not have time to cool down, but the ventilation still does not work and will not work.

And what about in the summer? In the summer months, it won’t get better, since in winter the temperature difference (internal and external) makes natural ventilation work, and when these temperatures equalize by the summer, the air flow stops.

Troubleshooting ventilation ducts

The first thing that comes to mind is the clogging of the ventilation ducts. Remove the grill with ventilation window and look into it. Debris found within reach can be manually removed or vacuum cleaned.

Removing garbage directly from the ventilation shaft is technically difficult, and this kind of independent action is prohibited to private individuals.

Clearance ventilation duct
The ventilation shaft, built of brick, has an uneven inner edge, its lumen is quickly clogged and can even become completely covered with dirt. Better if the barrel is made of more even concrete blocks.

If you suspect obstruction of the ventilation ducts, you should call specialists through the management company, in the arsenal of which there are the necessary diagnostic devices and tools.

There is a lot of construction waste in the found garbage. Unscrupulous builders, engaged in repairs and redevelopment, often intentionally dump litter into the ventilation shaft, without bothering to take it out into the yard.

The result is a blocked ventilation duct. The management company should also deal with such violations. But even without this, with each next year of operation, the dirt on the walls narrows the clearance of the ventilation duct, the draft weakens. In the ventilation system, dust settles, a web forms. From above, foliage flies into the mine, birds fall into it.

Damage caused by shrinkage of the foundation, cracking of walls and other consequences of the inevitable aging of the building contribute to this. Clogged channels do not cope with the task.

Planned revision of ventilation of apartment buildings

As ventilation ducts Since they are common for the house, their operation is provided by the managing organization, whose representatives are obliged to check the condition of ventilation, and if necessary, clean the mines and repair them on the basis of a license or conclude the necessary contracts with specialized companies.

Professional inspection of the ventilation shaft
You can eliminate the blockage in the ventilation duct from the roof of the house, if it is located at the level of the upper floors. At the bottom, you often have to disassemble the shaft wall from the stairwells

The rules for checking ventilation provide answers to a lot of questions:

  • how often ventilation ducts are checked;
  • the presence of traction should be checked in apartments or it is enough to examine only the ventilation shaft;
  • Is the frequency of ventilation checks in the bathrooms and the kitchen the same?
  • is the managing organization responsible or is the owner responsible for checking the draft in the apartment?

In apartment buildings, inspections of ventilation ducts are carried out 1-2 times a year - it depends on whether there are gas appliances or only electricity is used. In the presence of gas, ventilation is checked twice - in summer and winter. If serious malfunctions are identified, it is forbidden to use gas appliances until they are rectified.

You can not arbitrarily remodel, repair, improve ventilation in the apartmentsince it is interconnected with the social system. All actions are coordinated with the relevant services.

Problems in a working system

It so happens that ventilation works for a long time, remaining in good condition, and then suddenly stops or starts to drive air in the opposite direction. Indeed, if we discard all the reasons described above, it turns out that the problems with ventilation do not end there.

We will analyze how the natural ventilation of an apartment building with a vertical prefabricated channel is arranged.

The ventilation scheme in an apartment building
Air enters the individual channel, rises parallel to the common shaft and enters it through the opening on the next floor, without reaching the plug separating the next individual channel belonging to the upper apartment

The main ventilation shaft leads from the first floor to the attic. All apartments are equipped with individual ventilation moves (sleeves or satellite channels).

Each of them from the ventilation outlet in a particular apartment rises up one floor and penetrates the main channel slightly below the same individual ventilation passage belonging to the apartment a floor above.

Air from the apartment through a satellite channel moves into a common shaft and there it moves further to the attic, and from there to the street. These satellite channels feed the general flow, and if air ceases to flow through them, then its volume and speed of movement along the main shaft will also decrease.

A sleeve that has ceased to function in one apartment will not disable all ventilation along the riser in a 5th, 9th or 16th floor building. But the more apartments fall out of the general ventilation system, the weaker it is. Having reached a critical limit, ventilation refuses: the airflow going to the attic level is so frail that it cannot push itself further.

Moreover, it goes down, and the channel-sleeves of the last two floors are the first to pull it back. To protect the upper floors from backdraft, individual channels are led directly to the roof. But to find out why the flow of air to the ventilation shaft is reduced, it is necessary in individual apartments.

The internal structure of the ventilation unit
Near the common shaft are individual ventilation ducts of the kitchen and bathroom.At the level of each floor, they have access to a common shaft and are covered with plugs.

Consider a two- or three-room dwelling, in which the kitchen and bathroom / toilet are separated at different ends, and in this connection two independent ventilation ducts are built. One serves the kitchen and the other a bathroom. This pair of channels draws stagnant air from the apartment into the ventilation system, it is replaced by fresh air.

Only the flow of air outside is considered correct. The widespread replacement of wretched but breathing wooden window frames with double-glazed windows violates the circulation process. They do not let in air, temporary opening of windows for ventilation does not help, since for the ventilation to take place, the air flow must be constant.

If the front door does not close so tightly, then air can come from the stairwell. It is not better in quality than that available in the apartment, but it supports the viability of ventilation. Although is it necessary to have such a ventilation system in which the air inside the house moves - with the smell of tobacco (they often smoke in the stairwell), etc.?

When there is no internal air flow through the front door, one of the two ventilation ducts available in the apartment (with a stronger draft) will begin to draw in air from the second channel. Those. going on tipping of draft in one ventilation duct at the expense of another. The effect is the same - someone else's exhaust air in the apartment, a lot of unwanted odors and aromas.

Vagaries of ventilation on the top floors

In addition to the vertical outlet of the ventilation shaft to the outside, there are other engineering structures of the ventilation system - with a horizontal connection box in the attic having a single exit to the roof, and with a large intermediate ventilation compartment-drive, which is the attic itself, from where air moves outward through a single common ventilation shaft .

Common ventilation schemes for apartment buildings
In many residential apartment buildings, one of these two ventilation schemes is found - with a horizontal collection channel (on the left) or with a warm attic (on the right)

In order for the ventilation in the apartments of the upper floors to work normally, the air must pass up the vertical shaft at least a few meters, but the attic is an obstacle to this, and the following happens:

  • in the scheme with a horizontal box - the air from all floors reaches the attic level and meets the ceiling of this duct on the way. Without turning horizontally, he seeks to find other passages, and often located near the ventilation arms of the upper floors;
  • in the scheme with access to the attic - in the satellite channels of the upper floors, the air flow does not accelerate enough to flow into the voluminous attic, and the air exchange in the apartments slows down.

In the first case, the ventilation is forced in the opposite direction, and all the smells from the lower apartments penetrate the residents above. Two solutions to the problem are to modernize the junction box, if technically feasible, or to separate the satellite channels of the upper floors from the box, insulate them and bring them directly to the shaft facing the roof.

In the second case, on the upper floors there is already a weak draft, and if the attic is blown, it can also reverse. Therefore, the length of satellite channels on the upper floors is increased, displayed in the attic higher and turned to a common shaft, so that the air flow from the lower floors carries with it weaker upper flows.

Cleaning the ventilation ducts

As for the main ventilation shaft, private individuals should not touch it. Contact the management company with a complaint about poor ventilation and wait for specialists. Before their arrival, neighbors must be notified so that they can protect themselves from possible black fine dust exhaust from the ventilation grilles.

Cleaning the ventilation duct with a brush
The classic way to clean the ventilation ducts with a ruff.But it is confidently superseded by modern methods based on the use of technology

Based on the results of the inspection of ventilation ducts, the commission issues an act with instructions for operation and repair.

In the process of examination, the cross section of the channels is measured, the length of the narrowed sections, paying attention to the condition:

  • mine walls (cracks, etc.);
  • connecting pipes;
  • horizontal segments;
  • air inlets, heads, hatches, etc.

To clean the strokes, industrial vacuum cleaners, mechanical devices with a variety of nozzles are used. The mine is illuminated by floodlights, its entrails are inspected using digital cameras and video cameras.

Does not require much time and cost repair of ventilation ducts. The destroyed sections of the channel are restored by installation inside the pipes of metal or ceramic, lining with fastening solutions, lining with polymers.

The ventilation passage from the apartment to the communal mine can and should be cleaned independently:

  • move the furniture away, remove excess objects, push the step ladder to the wall;
  • glue paper or newspaper on the wall below the ventilation hole with masking tape so as not to wash wallpaper or tiles from dirt, cover the floor;
  • remove a decorative lattice;
  • Put gloves on your hands and carefully scrape dirt and debris out of the ventilation duct.

Remove any residual dirt with a vacuum cleaner, replace the previously washed grate or replace it with a new one. After cleaning, check the draft again with the window ajar.

Methods for optimizing ventilation in the apartment

If the ventilation in the apartment is disturbed due to the installation of sealed double-glazed windows, then use the ventilation mode. We are familiar with summer airing - this is a fully open sash or its position at an angle due to a swing-out mechanism.

Winter is also called micro-slit, to switch to this mode, you need to turn the window handle with the shutter pressed to deploy 45º.

Microventilation of a plastic window
In the winter airing mode, the gap formed between the sash and the frame cannot be seen visually, but the air seeping into it is quite enough to maintain ventilation

Another way out is to use supply ventilation valves. They are mounted in the outer wall, in the joints filled with mounting foam between the window block and the wall, in the window profile, below the window sill.

In winter, the ventilation valves draw a little cold, but in hot summers the air may not flow into them at all. Therefore, it makes sense to additionally equip the entrances to the ventilation ducts with exhaust fans.

The bathroom has to deal with high humidity. Waterproof fansbuilt into the ventilation holes turn on themselves, responding to increased humidity, and turn off when the vapor evaporates, the air becomes drier.

In the toilets, a fan with a motion sensor and a timer can be mounted in the ventilation system. The fan starts to rotate automatically when someone enters, and stops after the time set in the timer. In the kitchen, fans with an air quality sensor that capture cigarette smoke and other unwanted odors will benefit.

Supply air valve
The throughput characteristics of the valves are different, there are adjustable models, usually put two to four valves per apartment

And finally about cooker hoods. Their power is enough to skip a significant part of the air available in the apartment during operation. If there is not enough natural air flow, the return of air from the ventilation shaft of the bathroom will inevitably begin. Limit the use of the hood and open the window when you turn it on.

Conclusions and useful video on the topic

What to do if ventilation does not work:

As soon as you find any abnormalities in the ventilation system, immediately take action.If you can’t do it on your own, invite specialists.

If you have questions when familiarizing yourself with the information presented by us, there is valuable information, found flaws in the article, we invite you to comment. Please write comments in the block below.

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Visitors Comments
  1. Dmitry

    Poor ventilation is one of the main causes of all kinds of human diseases and a prerequisite for the spread of any unsanitary infection, such as a fungus from dampness and the like. I live in an old house, which is about 70 years old, here the air does not circulate even when I’m on my own, and, of course, with the help of acquaintances, I cleaned it, nobody cared about this problem. I found the optimal solution - I installed a one-piece ventilation system with wiring ducts in all rooms, I already have four of them). Now everything is fine, the microclimate is settled!

  2. Anastasia

    With ventilation in multi-storey buildings, there are different stories. There are ventilation units combining exhaust ducts from apartments on neighboring floors in pairs across two floors. If a neighbor has a powerful forced exhaust, then the air flow can completely block the air draft from another apartment. Therefore, in order to notice this on time, it is necessary to periodically check the operation of the ventilation duct. Previously, everyone used burning matches for this purpose, were there really explosions from this?

    • Expert
      Alexey Dedyulin

      Checking the draft in ventilation with a lit match, candle or lighter is the last century, plus it’s not safe. Okay in the living rooms, there’s nothing to burn there except for dust, but the dust also can be different. And now we’ll smoothly transfer to the kitchen, where almost everyone has an extractor fan. What, together with the air from the kitchen, enters the ventilation duct? That's right, these are particles of fat that accumulate there for more than one year, plus annual dust and an excellent mixture is obtained, which can break out not only from the fire, but even from a small spark!

      Remember, the easiest and safest way to check the ventilation is to attach a piece of paper to the hole. If it holds, it means that the ventilation is working properly.

      • Victoria

        apply a piece of paper with open or closed windows? with the windows closed - we have a reverse traction

  3. Ruslan

    We also had a story with ventilation, moisture constantly stood in the bathroom, a fungus began to appear. Although before this 3 years everything was fine. It turned out a neighbor laid the hood from our apartment with tiles. And we had air, and the ventilation only worked for him. So now we check it ourselves, once a month.

  4. Shoals of the inspector ... Who measured the speed in the grate in the grate itself (which is clogged with dust, as seen in the video) from the beginning, without removing it. And then the service that cleans to measure speed is already in the hole (opening) and they scratch that it has increased and there is a margin ... Frames. I'm just laughing ...

  5. Galina

    Your article is suitable for houses of a new construction, but I need an article for houses of the 70s.

    What section should the ventilation duct be? Does the channel cross section affect the operation of the hood? An exhaust hood does not work well on my 4th floor in a 5-story brick building.Last October, I installed a ventilation grill, so it is still clean, although it should already be dirty.

    Previously, I did not pay attention, but since July this year, the hood sometimes began to work in the opposite direction. In August, it blew so that I could not light a match and a gas stove. Whatever the Criminal Code has done, but things are still there. I began to sneeze for no reason, although I always sneezed only when I got a cold. In summer, my windows are always open. I always always open only one window so that there is no draft. Here I am looking for the causes of poor operation of the hood!

  6. Oksana

    We live on the 5th floor, 2 small children, the neighbors below smoke in the toilet and all the smoke in our apartment, there’s nothing to breathe at all. There are no forces anymore, the child refused to go to the toilet, as he says he suffocates from smoke. The window always has to be kept open, but winter is coming and how to be? I do not know what to do.

    • Expert
      Alexey Dedyulin

      Hello. Call for examination an authorized person, for example, a district police officer, and then you can file an application under article of the Civil Code of the Russian Federation Article 304. Protection of the rights of the owner from violations not related to deprivation of possession in court, housing inspection, consumer protection supervision.