We are often asked when should the ventilation ducts of a housing association or residential apartment be cleaned...
At IVAeris Oy, we know the answer: ventilation ducts should be cleaned when they are actually dirty. There is no one-size-fits-all schedule. Some claim that cleaning is necessary for health reasons, but in reality, there is no conclusive evidence to support this. The dust and dirt that accumulates in the ducts usually stays there and doesn’t spread into the indoor air – so even if the ducts are dirty, it doesn’t automatically mean that the indoor air is contaminated.
So why clean them? Cleaning the ducts is a smart way to ensure that your system runs optimally, lasts longer, and saves energy. An unmaintained system consumes more energy and requires more repairs. The law is also clear: in certain places, like hospitals, schools, and restaurants, ventilation ducts must be cleaned regularly – often every five years, but in professional kitchens, even annually.
So, don’t buy into the health hype, but don’t skip maintenance either. The schedule depends entirely on the specific needs of your property and legal requirements. A smart property owner ensures regular maintenance of ventilation systems to keep them in good condition and running efficiently.
What does the law say about ventilation cleaning?
In Finland, several laws and regulations govern the cleaning of ventilation ducts to ensure safe and healthy indoor air, as well as to prevent fire hazards. Here’s a look at the key regulations:
Rescue Act (1078/2018, Section 13)
It is the responsibility of the building owner and operator to ensure that ventilation ducts and equipment are regularly maintained and cleaned to prevent fire hazards. This law applies to all buildings and obligates property owners to take care of fire safety within ventilation systems.
Ministry of Defence Decree (712/2017, Section 63)
This decree applies to the industrial handling and storage of hazardous chemicals. It requires that ventilation ducts associated with chemical handling must be regularly maintained to ensure safety during the storage and handling of chemicals.
Ministry of the Interior Decree on Ventilation Duct Cleaning (802/2001, Sections 2-3)
This regulation covers all types of ventilation ducts, whether natural (gravity-based) or mechanical. The decree specifies cleaning intervals for ventilation ducts:
Annually cleaned ducts: Ventilation ducts in professional kitchens, carpentry workshops, bakeries, and other industrial spaces where flammable substances easily accumulate must be cleaned at least once a year.
Ducts cleaned every five years: For example, the ventilation ducts in hospitals, schools, hotels, and restaurants must be cleaned at least every five years.
The Ministry of Social Affairs and Health regulations
The Ministry of Social Affairs and Health (STM) has established several regulations related to indoor air quality in both workplaces and residential environments:
HTP values (STM 538/2018): The permissible levels of air impurities in workplaces are strictly defined, such as the allowable concentration of carbon dioxide during an 8-hour work shift, which is set at 5000 ppm.
Residential ventilation (STM 545/2015): This regulation mandates that ventilation must be sufficient to ensure proper indoor air quality and moisture control, although it does not specify particular cleaning intervals.
In summary, regular maintenance and cleaning of ventilation ducts is a legal obligation in many cases, with a particular focus on fire safety. The legislation also references indoor air quality, but as previously mentioned, there is no scientific evidence that duct cleaning directly improves air quality. However, there are exceptional cases, such as mold in supply air ducts, where cleaning must be done immediately.
What does the industry say about duct cleaning?
In the ventilation industry, there seems to be an endless variety of recommendations and opinions, yet many contractors still struggle to answer a simple question: how often should ventilation ducts be cleaned? This is because the regulations for residential buildings don’t provide clear guidelines on this matter. The industry is used to everything being regulated with specific laws, but when it comes to cleaning intervals for ventilation ducts in residential properties, things get a bit murky.
If you’ve read the legal texts mentioned above, you’ve likely noticed that there’s no direct mention of cleaning intervals for residential apartments, housing associations, or consumer properties. This has led to the widespread misconception that a five-year cleaning interval is the “standard” for everyone. However, that’s not the case. Legislation sets clear rules for places like hospitals, restaurants, and industrial facilities, but the cleaning interval for residential buildings is not mandated by law.
Indoor Climate and Ventilation Guide (June 11, 2024)
Talotekniikkainfo published an updated Indoor Climate and Ventilation Guide (June 11, 2024), and here’s the straight talk. This guide was produced by Talteka (Finnish Building Services and Trade Association) and is based on the collaboration of industry experts. It summarizes everything you need to know about duct cleaning.
Here are a few key points you can’t ignore:
Assessment of cleaning needs: The need for duct cleaning must be checked at least every five years. Highly demanding spaces, such as commercial kitchens, require cleaning at least once a year to ensure the system operates safely and efficiently.
Cleaning access doors: A sufficient number of access doors must be installed in the duct system to ensure proper cleaning. In horizontal ducts, access doors are recommended every 10 meters. In more demanding environments, they should be placed every 3–5 meters.
Cleaning certificate: A cleaning certificate is an important document that must be kept, for example, in the kitchen’s self-monitoring file. It serves as proof that the ducts have been cleaned according to regulations.
Cleaning methods: It’s essential to ensure that the cleaning process doesn’t damage control devices, silencers, or other components. Every cleaning must be done in a way that maintains system performance and avoids any damage to the ducts.
Cleaning ventilation ducts: Bottom line
When looking at ventilation ducts, many people panic at the sight of dust in the exhaust ducts and immediately think that the indoor air is contaminated. But here’s the key point: in exhaust ducts, the air is moving out of the property, and the dust inside does not make its way back into the indoor air. So, no need to panic. The real question is whether enough dust has accumulated to affect the efficiency and energy consumption of the ventilation system. If the answer is yes, then cleaning the ducts is a smart move.
On the other hand, dust in the supply air ducts could affect indoor air quality, but supply air always passes through a filter, meaning the ducts don’t really get dirty. In fact, supply ducts are often nearly clean even after decades, though many people find that hard to believe. The ring of dust that sometimes gathers around supply air vents is often mistaken as a sign of dirty ducts, but this dust comes from turbulence in the airflow and is from the indoor air, not the ducts.
Regular cleaning is legally required in many cases and is important for fire safety and efficiency. But if the law doesn’t mandate it, unnecessary cleaning without a valid reason is a waste. If you’re unsure whether cleaning is needed, get in touch with us – we’re happy to help assess the situation. You can also schedule a ventilation inspection, where our expert will check your system and provide recommendations.
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IVAeris Oy
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