EU norm on Duct System Cleanliness
The need for clean air conditioning and ventilation systems has been recognised formally by the European Union in pre-standard prEN 15780 ‘Ventilation for buildings – Ductwork – Cleanliness of ventilation systems’, which lays down cleanliness standards to be met in a variety of situations. This is part of the CEN program for standardisation across Europe.
You can download a preview of the standard as a pdf here. Also available on our PDF Files page is an analysis of the work on duct cleanliness measurement methods done by Birgitt Mueller et al at the Technical University of Berlin under the EC-funded Airless program. I did this back in June 2008, but have now been persuaded that the Finnish method is better. The Finnish 'brush' method uses a tube in front of the sampling filter capsule and this means it aslo works well for circular ducts, which is a big advantage, especially in Europe where circular ductwork is more common.
This underpins the measurement methods and values in prEN 15780.
Finally, I have put up a comparison of values between HVCA/NADCA style Vacuum testing and the Finnish Vacuum Test which has been adopted by the CEN. This gives a good indication for those more familiar with the US/UK method as to what the levels mean in practice. It's a little more stringent for post-clean acceptance and that's no bad thing if it keeps the industry on its toes!