Lars Due
Bibliographic info:
9th International BUILDAIR Symposium, 8-9 May 2015 Kassel, Germany

Purpose of the work

Since the introduction of the Blower Door test to the building code in Denmark back in 2006, there has been a move toward encouraging the sector to raise the quality level of tests performed around the country. The building code requirements in Denmark are:

  • 2006 w50 ≤ 1.5 l/(s m2) ~ n50 = 2 h-1 (single family) ~ n50 = 0.8 h-1 (66000 m3 office)
    • 5% taken by authorities to test
  • 2010 w50 ≤ 1.5 l/(s m2) ~ n50 = 2 h-1 (single family) ~ n50 = 0.8 h-1 (66000 m3 office)
    • 5% taken by authorities to test
    • w50 ≤ 1.0 l/(s m2) ~ n50 = 1.4 h-1 (single family) ~ n50 = 0.54 h-1 (66000 m3 office)
    • 100% must be tested
    • w50 ≤ 0.5 l/(s m2) ~ n50 = 0.7 h-1 (single family) ~ n50 = 0.27 h-1 (66000 m3 office)
    • 100% must be tested, and expect that there will be a requirement in the building code that the test operator and company conducting the test are certified.

The building code in Denmark is very favourable for the Blower Door sector, and even better times are to come, when we go from 5% for testing to 100%. These conditions attract many companies with varying degrees of interest, and a certification of the Blower Door test is starting to be desired by the construction industry and authorities.

Method of approach

In 2008, our trade association, “klimaskaerm” (comparable with FLIB e.V.), started a voluntary certification system in collaboration with Danish Standard. The system costs about 4500 euros per year, and was never very successful; only 3 companies were certified from the start.

In 2013, we changed the agency to BK, which could provide the same service for 1000 euros, and now that the systems have been started, there are 14 certified companies and more are on the way.

Denmark is a little country and only 15,000 new family houses are built per year, but to test at 100% and with 14 companies, we get busy! So we must have more certified companies.

Today, we have a certification system in which the company must have a quality system in accordance with ISO9001, and the operator must go through a course and pass an examination.

The system helps to raise the quality level of the work performed, and gives us a good foundation to develop and discuss building code demand and methods of measurement.


Certification of the Blower Door test in Denmark is still a voluntary system, but we have hopes that in 2020, there it will be required in the building code. And we can now see that the construction industry is focusing more and more on the benefits in ensuring that the tests carried out are correct


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