ABOUT CLEANING THE AIR DUCTS: METHODS, RULES, FREQUENCY from Alan's blog

To ensure that the air in the room is always clean and updated in a timely manner, it is necessary to periodicallyair vent cleaning

Now we are not talking about chimneys, which are contaminated with soot - the usual ventilation system (both supply and exhaust) also needs cleaning.

There are always small particles of debris in the air around us, which can get into the ventilation duct. For an exhaust duct, these are:

• dust;

• fat (which is removed through the hood when cooking);

• chemical compounds formed when using household chemicals (detergents, washing powder) and when smoking;

• to a lesser extent - other small particles that can get into the ventilation.

Since the air in the apartment is usually clean, the exhaust ventilation duct becomes polluted relatively slower than the supply duct.

If we are talking about supply ventilation (going from the street to the room), then the pollution rate will be significantly higher. The reason is that the outside air is much dirtier than the room air (when it comes to the city).

Grease-contaminated air duct

In addition to dust, it contains:

• pollen;

• harmful compounds from car exhaust, industrial emissions.

In addition, the supply ventilation channels can be clogged with larger debris: leaves, poplar fluff, small insects. Of course, if there is a ventilation grill at the entrance to the air duct, then this can be avoided, but air with a mass of impurities will still pass through and pollute the system.

Separately, it should be said about natural ventilation and forced ventilation. In the first case (when air passes through the duct without using fans), pollution will occur more slowly. In the second case, when more air passes through the system, it will also become polluted faster.

The cross-section of air ducts - even in small private buildings - is quite large, therefore, on straight sections, pollution, although it goes, is very slow.

Much faster the places where small particles have something to "catch on"become contaminated  :

• bends;

• branching of ventilation ducts;

• diameter differences;

• filters (this does not mean the filter element itself, but the areas near it, where the filter housing is built into the ventilation system);

• valve;

• fans;

• heat exchangers, heaters, coolers, humidifiers, dehumidifiers;

• grilles, anemostats, diffusers.

Dirt accumulates the fastest around these areas. Later, when a decent layer of pollution has already formed in the "problem" areas, it begins to expand further along the duct.

Ventilation contamination is dangerous for several reasons:

1. The inner section of the ventilation duct is reduced. As a result, less air passes through the duct.

2. Further clogging of the air duct with dust is accelerated. If small particles were able to catch somewhere - in this place the deposits will grow faster and faster.

3. The load on the fans increases, which means that their wear is accelerated.

4. The indoor climate is deteriorating: the level of humidity rises, the air may contain harmful compounds that cannot be quickly removed, the room becomes hotter and more stuffy. As a result, it harms both the human body and the room itself (the risk of fungus and mold growth increases).

5. The risk of multiplication of pathogens increases, for which a dirty environment is favorable. The most common consequence in humans is an aggravation of allergies.

If we are talking about ventilation not in an apartment or house, but at some industrial facility, then dust deposition in the duct is also fire hazardous. After all, dust easily flares up, which means that in the event of a fire, the air duct can easily become one of the paths for the spread of fire throughout the building.

Such a fire can become especially dangerous at objects where some flammable substances are present in the working area (which means that they will be deposited in the ventilation system). At the same time, keep in mind that dust can ignite not only from an open fire: it can also be caused by a spark caused by a static charge that has accumulated in the air duct.

To understand that it's time to clean the air duct, you don't have to look into it regularly.

There are several signs by which you can determine that the system needs cleaning:

1. The room became stuffy and hot, if other conditions (weather, operation of ventilation and climatic devices) did not change.

2. Dust builds up on floors and furniture very quickly.

3. Cobwebs accumulate on the ventilation grill and around it (both exhaust and supply).

4. Drafts that previously occurred when opening windows or doors are now weaker, or disappeared altogether.

In addition to the above "signs", there is also a practical way to check the performance of the ventilation shaft:

1. Remove the ventilation grill from the vent.

2. Rinse the wire rack.

3. Replace the grill. If the grill is not too dirty, the first 2 points can be skipped.

4. Open a vent or window.

5. Attach a piece of paper to the ventilation grill. If it is "pulled" to the grate, it means that there is traction, and the traction is good. Please note: thick paper will not work, because even good traction will not always be able to "pull" a heavy sheet. Better to use half a notebook sheet, a piece of toilet paper, or a scrap of newspaper.

If you notice the "symptoms" listed above, it's time to check the condition of the duct.

This is done visually: the inner surface of the ventilation ducts is examined and the amount of deposits is determined.

You can conduct an inspection in the following ways:

1. Through a special hole - a hatch. The inspection hatch in ventilation systems must be designed when laying air ducts. However, the hatches are usually located far from each other, so they only allow you to inspect a small part of the system.

2. Removing the ventilation grill (especially important if there is no inspection hatch). This type of inspection allows you to see a small part of the duct, but it does not require special equipment. Relevant if you want to check the status, but there is no hatch in the system (or there is one, but in another part of the system).

3. Remotely, using special video equipment. This option allows you to evaluate any, even the most narrow or geometrically complex section of the duct.

If the inspection is carried out by specialists, they may have at their disposal equipment for video inspection. It can be an endoscope with a camera and illumination, which transmits video to the screen, allowing you to evaluate all parts of the ventilation system.

In practice, it happens that in many buildings, ventilation systems are not cleaned for years (and in ordinary apartment buildings - even for decades).

In fact, strict inspection and cleaning times exist only in some industrial plants. This primarily applies to buildings in which the production process leads to rapid contamination of the system. For example, this is true in the food industry - extracts at such enterprises draw in fat and flour particles. For such systems, inspections and cleaning can be carried out frequently - and several times a year.

In residential complexes with management companies, as well as in commercial real estate, in which there are no factors that accelerate ventilation pollution, periods of regular inspections can be set, usually once every six months or a year. Such work is carried out by the employees of the management company (or specialists who act on the order of the management company - if its staff does not have “its own” employees of such a profile).

It is recommended to independently inspect the ventilation ducts in their houses and apartments periodically, also about once a year. Cleaning - carried out as needed.

Methods for cleaning the air duct according to the principle of affecting deposits can be divided into:

1. Chemical.

2. Mechanical.

3. Cryogenic.

Dry cleaning is  designed to remove fat deposits (which are almost impossible to remove mechanically completely).

The principle is to spray a special composition over the entire surface of the ventilation ducts, which corrodes plaque. After that, the exfoliated deposits are carried out along with the air, or are sucked out by a vacuum cleaner. This method of cleaning is usually used in the kitchens of restaurants, bars, cafes, canteens, and other catering establishments.

Mechanical cleaning  (simply scraping off plaque from the canal walls) can be performed using various equipment:

1. A metal brush on a cable (in fact, it works on the same principle as a cable for cleaning a sewer). To increase efficiency, the cable can be electrically driven. Suitable for not too severe contamination, if there is not a lot of grease in the deposits.

2. Installation consisting of a mechanical cleaning device and a vacuum cleaner. In this case, the brushes of the cleaning device scrape off the plaque, and the vacuum cleaner immediately sucks it off. This method allows you to clear more serious pollution.

3. A robot equipped with a video camera and brushes. It allows you to work not "blindly", but to control the process on the monitor.

The removed deposits can be removed either naturally (carried away with the air stream), or using a vacuum unit (in fact, a powerful vacuum cleaner). It connects to the duct and sucks in all the dirt.

Cryogenic blasting  is a relatively new method, which is the most gentle and "clean". Purification is carried out with the help of "dry ice", which is fed into the ventilation duct from a special installation.

Contacting the walls of the air duct, the granules of "dry ice" instantly evaporate, creating microexplosions. It is they who clean off all plaque from the surface, while not damaging the walls themselves. In a microexplosion, only carbon dioxide remains from the granule, which is removed through the ventilation duct.

After such a procedure, the cleaned deposits are either removed from the duct in a natural way (carried away with the sweat of the air), or removed with a vacuum cleaner

Immediately about the basic rule: residents of apartment buildings can independently clean only the ventilation duct section that runs from the apartment to the "common" mine. Mine - refers to the common property, and only employees of the management company or the housing office can clean it.

If you notice that the ventilation in the apartment has deteriorated, you can first try to clean "your" section of the ventilation duct. It is recommended to use personal protective equipment for work - gloves, goggles, a “petal” respirator.

The stages are:

1. Remove the ventilation grill. It needs to be cleaned and rinsed.

2. Clear space around the vent.

3. It is better to cover the floor around the hole with something - as dust and other deposits can fall out of it.

4. Use a flashlight to visually inspect the area as much as possible. If you have a monopod and an action camera at home, these gadgets can seriously help when examining. Start filming, and slide the camera on a monopod into the ventilation duct.

5. Manually (with gloves, of course) scoop out large debris from the canal - if any. It is worth working carefully: inside the ventilation duct there may be nails, glass, and protruding sharp parts of a stone or frozen solution.

6. Use a metal brush to scrape off deposits from the entire surface of the duct.

7. Sweep out debris with a broom.

8. Use a vacuum cleaner to remove fine dust from the channel.

9. Replace the grate.

10. Check for improved traction.

Usually, if the draft in the air duct of the apartment has deteriorated, cleaning "your" area can help in rare cases. Therefore, after you have cleaned the ventilation duct to the common mine mine, it is better to call specialists who will take care of its cleaning.

In this case, it is recommended to walk along the entrance and warn the neighbors whose apartments are located above us and below you. When cleaning, dust may be emitted from the ventilation system and noise may be heard.

In combination with cleaning the surface from deposits, disinfection should also be performed - neutralization of microorganisms that could multiply in the ventilation system.

For this, after cleaning, another procedure is performed - spraying inside the system of agents based on hydrogen peroxide, peracetic acid or other reagents that kill bacteria. Such procedures can only be performed by specialists - they cannot be carried out on their own.