Luchtdichtheid    Airtightness

Additional specifications for the measurement of building airtightness

In Belgium each of the 3 Regions, i.e. Flanders, Wallonia and Brussels, are individually in charge of their own regulation on the energy performance of buildings. All 3 of them have introduced mandatory proof of compliance with the EPB-requirements on the basis of an as-built dossier, which has to be made up upon completion (or sufficient advancement) of the works.

In this context of a posteriori proofing of the energy performance, the authorities are in a position to require an actual measurement, rather than design estimates, as only evidence of achieved airtightness, when a non-default envelope airtightness is used in the determination of the overall energy performance determination of the building. Each of the 3 Regions specifies in its executive order that in case an airtightness test is done, it should be performed in accordance with NBN EN 13829:2001. However, this standard allows for 2 variants, and leaves a number of issues unanswered. Therefore, the 3 regions have collectively established complementary specifications in order to have unambiguous rules for all envelope airtightness measurements in the framework of their EPB-regulations.

An informal English translation of these texts is available.

A first document lists the complementary specifications.

• For the operators of airtightness measurements, a thorough knowledge of the full "Specification Document" (in combination with the standard) is of course necessary.

• The text also concerns the calculation of the E-level: the measured result should be introduced in a correct way in the EPB-software. In the annex A of the “Specification Document”, the conversion of the measured “large V₅₀” to the useful “small v₅₀” using the test area A_test is explained.

• Finally, some aspects are also important for designers and prescribers: for them in particular paragraphs 2 and 4 of the “Specification Document” are relevant, because some aspects of the design have a direct impact on the measurement result. For example, the choice for an open combustion device or a kitchen hood without any closing valve will lead to a less good result. They should also ensure that the additional EPB-specifications are prescribed, whenever a measurement is carried out for an EPB-declaration.

In paragraph 10 of the "Specification Document", the additional specifications are summarized.

A second text gives the argumentation for the choices which have been made.

For official use, please refer to the original Dutch or French texts only.