How is the cleaning of natural air ventilation systems performed?
- Mikael Denut
- Jan 27
- 6 min read
Updated: Apr 1
Are you looking for reliable information on cleaning ventilation ducts? There is a lot of advertising in the industry, but finding clear and factual information about the maintenance of gravitational ventilation—that is, natural ventilation—can be challenging. Our goal is to provide you with evidence-based information: we address the importance of cleaning ventilation ducts, the proper cleaning intervals, and practical implementation, especially in housing companies. We explain the real benefits of cleaning ventilation ducts on indoor air quality and fire safety, and critically assess common marketing claims, such as unnecessary duct disinfection.
This guide focuses specifically on the cleaning of gravitational ventilation, which differs in methods from cleaning a mechanical system. You will learn how to properly and safely clean the ducts of gravitational ventilation systems. (If your building has mechanical ventilation, you can find the instructions for cleaning it in our separate article “How is mechanical air ventilation duct cleaning performed?”)
Previously, regulations regarding the cleaning of air ventilation ducts were based on the Ministry of the Interior’s decree 802/2001. However, this decree became outdated on January 1, 2007, as it was issued under the now-repealed Rescue Act and lacked a specific validity period. No new decree has been issued since, meaning the cleaning and maintenance of air ventilation ducts are now based on the general obligations outlined in the Rescue Act.
According to section 13 of the current Rescue Act (379/2011), the owner, holder, and operator of a building are responsible for ensuring that air ventilation ducts and equipment are maintained and cleaned to prevent fire hazards. This responsibility applies to both common areas and spaces under the control of individual occupants.
While the Rescue Act allows for detailed provisions to be established through a Ministry of the Interior decree, no such decree has been issued so far. Consequently, it is recommended to follow industry best practices and, for example, the SFS-EN 15780 standard, which provides guidance on the timing and execution of cleaning.
When and why should cleaning of natural air ventilation system be done?
The cleaning interval for natural ventilation systems depends on the building’s usage, the system’s condition, and any indoor air quality issues. Generally, it is recommended to inspect the system regularly and clean it at least every 10 years. If the system shows malfunctions or its contamination affects indoor air quality, more frequent cleaning is advisable.
A thoroughly cleaned ventilation system not only improves indoor air quality but also prevents fire hazards and supports the system’s energy-efficient operation. It is the building owner’s and user’s responsibility to ensure proper maintenance, carried out by professionals when necessary.
What is natural air ventilation cleaning?
When cleaning natural air ventilation systems, it is crucial to avoid using rotary brush shafts on ducts made of construction materials, as they may suffer mechanical damage. Our team ensures that all cleaning is performed using methods suitable for the specific system. Cleaning natural air ventilation systems involves clearing the ducts so air can move freely without the aid of fans or other mechanical devices. The air circulates naturally between spaces, keeping indoor air fresh. You can learn more about natural ventilation in our article “ Mechanical vs. natural or gravity ventilation: which is better for controlling infectious diseases? ”
Why does natural air ventilation need to be cleaned?
Think of it this way: if you never cleaned your room, dust, dirt, and even mold spores could accumulate. The same applies to ventilation ducts! When ducts are clogged with dust and dirt, air circulation becomes inefficient, and indoor air quality deteriorates. Additionally, dust and dirt can cause allergy symptoms or even respiratory issues.
How is natural air ventilation cleaning performed?
Professional cleaning of gravitational ventilation is conducted methodically to ensure the best outcome. The process typically includes the following four key steps:
Inspection:
Initially, the overall condition of the ventilation system is assessed, and possible blockages or damages in the ducts are identified.
If these are structural ducts (e.g., brick or prefab ducts), special attention is given to:
Whether the ducts have an appropriate rain cap and bird netting.
Whether there are chimneys in the duct group; if so, they must be at least 150 mm higher than the ventilation ducts.
Whether moss has grown on the ducts. Moss retains moisture and can damage the duct structure, so it must be removed.
Cleaning:
The ventilation ducts are depressurized so that loose dirt and dust can be removed in a controlled manner.
The cleaning method depends on the material of the duct:
Structural ducts: Cleaned by brushing according to the guidelines of the Central Association of Chimney Sweeps. Mechanically rotating brushes must not be used to avoid damaging the duct structure and joints.
Spiral-welded ducts: Can be effectively cleaned with a mechanically rotating brush.
Filter replacement:
Once the ventilation ducts have been cleaned, it is essential to replace the filters on the supply air vents. Clean filters ensure that the incoming air is fresh and filtered, maintaining good indoor air quality.
Final inspection and adjustment:
Finally, it is confirmed that the entire gravitational ventilation system is functioning flawlessly and that air can flow without obstruction.
Precise adjustment of airflow in a gravitational system is challenging, but the freedom of air passages is verified. If necessary, airflow can be measured and optimized by adjusting the openings of the supply air vents for the best possible performance.
Steps in the cleaning process:
Depressurization: At the beginning of the cleaning process, the ventilation duct system is depressurized. This means that a negative pressure is created in the ducts, which helps to draw out loose dust and dirt..
Brushing: The ventilation ducts are brushed with a rotating brush only if they are spiral-welded ducts. Otherwise, a brush is used that is pushed through the duct so that the loose dust is drawn into the depressurizer.
Placement of the depressurizer: In cleaning a gravitational ventilation system, the depressurizer is usually placed outside the living area, for example, on the roof. This prevents the spread of dust and foreign matter into the living spaces.
Dust removal: The removed dust and foreign matter are expelled through the depressurizer. If the dust does not wash away with rain, the installer cleans the residue manually, ensuring that the environment remains tidy.
Regular and proper cleaning of natural ventilation systems is essential for maintaining system functionality and indoor air quality. Our professionals carry out cleaning with expertise, adhering to all necessary precautions and methods.
Why hire a professional?
A professional knows what they’re doing and has the right tools to ensure thorough cleaning. IVAeris Oy offers precisely this: skilled and reliable ventilation cleaning services to ensure your system operates at its best.
What can you do yourself?
In natural ventilation systems, it is advisable to use replacement air vents with filters, such as Velco vents. These filters collect dust and other impurities, so regular maintenance is essential. Fabric filters should be replaced at least once a year or as soon as they appear visibly dirty. Regular maintenance of filters ensures efficient ventilation and clean indoor air.
Velco replacement air valve filter replacement instructions
Grip the outer flange of the vent and pull it out of the wall.
Remove the old filter carefully (it may release a lot of dust) and seal it in a plastic bag.
Take a new filter, turn it inside out, and roll it over the vent’s frame wires, ensuring the seams are inside.
There is a black sealing ring on the neck of the valve. Pull the filter over the black sealing ring on the vent’s neck to ensure a tight fit.
Reinstall the vent by twisting it as needed, making sure it is securely attached to the wall.
The valve disc should be turned to the left at least half a turn from the “click point”. This will prevent the valve from closing completely at freezing temperatures and ensure continuous ventilation.
For a detailed guide, download Aeris’ instructions for Velco air vent filter replacement:
How can IVAeris Oy help you?
Assessment and diagnosis: Our experts evaluate your current ventilation system, identify potential issues, and provide a detailed diagnosis.
Tailored solutions: Based on our assessment, we recommend customized solutions to enhance your ventilation system, whether by adding vents, improving existing ones, or integrating mechanical elements to boost performance.
Maintenance services: Regular maintenance is key to keeping your system in top condition. We offer cleaning, inspection, and repair services to ensure continuous and efficient operation.
Upgrades and installation: If your system requires significant improvements or a complete upgrade, we provide installation services for new ventilation systems designed to meet the latest standards and your specific needs.
Why choose IVAeris Oy?
With our experience and expertise, we solve all ventilation-related challenges. Your health and comfort are our top priorities, and we deliver high-quality solutions that exceed your expectations.
Act now
Don’t wait until ventilation problems affect your health and comfort. If you suspect your ventilation system isn’t functioning properly or are concerned about indoor air quality, contact IVAeris Oy today.
Our fast and efficient service ensures a healthier and more comfortable living environment. Contact us for expert advice and the best solutions to maintain your home’s air quality.
WE KNOW, WE CARE & WE GET IT DONE
IVAeris Ltd.
010 206 3000
