Duct cleaning standards: EN 15780, VDI 6022 and NVRL

Which standards and rules apply to clean air ducts?

The overview below puts the frameworks side by side. Pay attention to the status column: some of the well known documents have recently been replaced.

In addition, the Dutch knowledge institute ISSO published a document in 2010 on quality requirements for ductwork systems in residential and non-residential buildings, and Eurovent gives practical requirements for inspection openings and cleaning methods in recommendation REC 6/7.

EN 15780:2025: what has changed compared with 2011?

EN 15780 is the European standard for the cleanliness of ventilation systems. The revised version appeared at the end of July 2025 via the Norwegian and British standards institutes; in Germany, DIN EN 15780:2026-07 was published with 49 pages, replacing the 2012 edition.

• Scope: new and existing systems, with or without air conditioning, over their entire service life.
• Kitchen extraction: the new version extends its application to the extract systems of commercial kitchens.
• Exclusions: industrial, medical and laboratory facilities fall outside its scope, as do industrial process installations.
• Annex A: informative tables with cleanliness classes (A.1), inspection intervals per class in months (A.2), acceptable cleanliness levels (A.3) and requirements for new ducts (A.4).

According to cleaning company Hamster Cleaning, the standard for the first time contains guidance on grease thickness in commercial kitchen extraction. That is a secondary source; the exact wording can be found in the standard itself, which you can buy from NEN or another standards institute.

EN 15780 duct cleanliness classes and dust limits from trade publications

The limit values for dust on the duct wall are widely quoted, but in the sources used on this site they come from trade publications and not from the text of the standard itself. Use them as guidance and check the standard before putting them in a contract.

The same trade article mentions a risk assessment every two years, and every year in high risk buildings such as hospitals and laboratories. How to turn that into a schedule is explained under air duct cleaning interval. For offices, the page on ventilation in commercial buildings works this out further.

VDI 6022 ventilation hygiene: inspections of air handling

VDI 6022 Part 1 is a German guideline with hygiene requirements for the design, construction and operation of air handling installations. Its aim is air that is harmless to health. It is not Dutch law, but you can include it as a hygiene framework in a maintenance contract.

• Interval: a hygiene inspection every two years for installations with air humidification, every three years without (TÜV Süd).
• First inspection: before commissioning, after a major modification or if the installation has never been inspected (TÜV Nord).
• Content: assessment of the contamination in the ducts and microbiological testing of supply air and reference air.
• Independence: Eurofins advises keeping cleaning and the hygiene inspection separate.

In hospitals there is an additional obligation to have an air management plan for operating theatres. More on that under hospital ductwork cleaning.

NVRL quality mark and grease limits for kitchen extraction

The Dutch association of cleaning specialists for air handling systems (NVRL) drew up a quality mark scheme for the cleanliness of air handling systems together with TNO. The emphasis is on grease in the kitchen extraction of restaurants, hospitals, care homes and offices, and on industry.

There is no statutory cleaning frequency for the hospitality sector, says KHN (Royal Dutch Hospitality Association), but fire insurers do require regular maintenance. Rabobank advises at least once a year, and twice for a restaurant with deep fryers. The practical side is covered under kitchen extract cleaning.

Legal requirements: the Arbobesluit and the Bbl

Where the standards provide measurable limits, the laws establish the duty. The key articles at a glance:

• Arbobesluit Art. 6.2: sufficient uncontaminated air at the workplace (paragraph 1), installations always ready for use (paragraph 2), signalling of faults where health requires it (paragraph 4) and a link to the Bbl (paragraph 6). Note: Article 6.4 is about keeping out sunlight, not about ventilation.
• Arbobesluit Art. 4.5: anyone extracting contaminated air must at the same time supply sufficient clean air.
• Arbobesluit Art. 4.87b: measures against legionella in air humidification, with a risk analysis and a management plan.
• Bbl Art. 3.67 to 3.73: almost every existing building has a ventilation provision that prevents damage to health.
• Bbl Art. 4.122 to 4.132: ventilation requirements for new builds, with NEN 1087 for the capacity.
• Bbl Art. 3.143: every classroom in primary, secondary and special education has a CO2 meter.

For schools, the Dutch Frisse Scholen (Fresh Schools) programme ties in with this; see fresh air in classrooms.

What do the standards say about the cleaning method itself?

Besides cleanliness limits, guidelines also set requirements for the way the work is done. Those requirements determine which equipment you need.

• Accessibility: Eurovent specifies inspection openings no more than 10 m apart or after no more than two bends of 45 degrees or more, and for ducts larger than 500 mm a hatch of at least 500 x 400 mm.
• Dry or wet: dry methods are usually sufficient for supply and general extract ducts; commercial kitchens need wet methods.
• Negative pressure: every section being cleaned is kept under continuous negative pressure, with HEPA filtration of 99.97 percent at 0.3 µm if the extraction unit exhausts indoors.
• Verification: cleanliness is demonstrated with a surface comparison or the gravimetric NADCA vacuum test.

For rotary brushing in ducts of 100 to 600 mm up to 30 m deep, electric DC4 brushing machine for cleaning contractors is the purpose built tool; for narrow ducts with bends there is the air lance with camera. Sealing and negative pressure are handled with vent caps for duct cleaning and an extraction unit. The complete overview can be found under duct cleaning equipment for cleaning contractors.

From duct cleaning standards to a maintenance plan

A standard only becomes useful once you translate it to your own building. These five steps help:

1. Decide for each installation which framework leads: EN 15780 for general ventilation, VDI 6022 for air handling with hygiene requirements, NVRL for kitchen extraction.
2. Choose a cleanliness class that matches how the building is used.
3. Record inspection intervals and who carries out the inspections.
4. Describe the working method and the verification, as in cleaning ductwork professionally.
5. Archive reports, photos and measured values for the insurer and the auditor.

Not sure which machine matches your requirements? Then contact Lamers from Lamers.