Michael Pils
Bibliographic info:
11th International BUILDAIR Symposium, 24- 25 May 2019, Hannover, Germany

What is recommended in the way of building preparation (methods 1, 2, 3)?

For methods 1 and 2, the Austrian national annex to ISO 9972 page 6, Item 6.3, Table 1, applies. For method 3, there are no references in the national annex. In this case, ISO 9972 applies.

If method 3 is selected, is a checklist drawn up? Of interest is the issue of fixtures incorporated into the building envelope, like letterboxes, window rebate ventilation, WC fans and fire dampers.

There is no checklist for method 3.

Do definitions of the time of measurement diverge (5.1.3)? Is it also permissible to take measurements before completion of construction?

There are no deviating definitions for the time of measurement.

Have "special cases" been determined for calculating volumes and enveloping surfaces?

The volume and envelope area are calculated according to the requirements of ISO 9972 and the net floor area according to ÖNORM B1800.

Are instructions provided for individual room measurement (zone measurement)? For single room measurement, there are no national characteristics.

Is a recommendation made for determining measuring errors that differs from ISO 9972? No deviating calculation of measurement errors.

Are there special rulings for measuring very large buildings? Perhaps measurements on a random basis or zone measurement, etc.?

There are general instructions for calculating the number of samples, but they apply to all buildings. There is no separate regulation for large buildings.

Are national limit values defined taking into account building preparation and, if so, what are they?

According to the building code, the following generally applies:

  • For window ventilation – LWR 3.0 h-1
  • For a controlled ventilation system – LWR 1.5 h-1
  • For a passive house – LWR 0.6 h-1

The individual federal states have different funding guidelines, sometimes with a lower LWR. In Lower Austria, for example, the value is LWR 1.0. Basically, the air exchange for buildings with a ventilation system is cited on the energy certificate. This value is between 0.6 and 1.5 and is then applied to the BlowerDoor test. The stricter requirement is always the one that applies, meaning that if the energy certificate is stricter than the building code, the value on the energy certificate applies.


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