BD2011

Building and ductwork airtightness represent a key challenge towards very-low energy buildings and therefore towards the ambitious 2020 targets set in the recast of the energy performance of buildings directive.

The objective of the WTA* data sheet “Air tightness in existing buildings” is to support planners and contractors in modernizing and renovating buildings. Taking existing standards and regulations into account, the data sheet features the analysis of existing buildings, professional planning and implementation, as well as air tightness requirements (n50, q50) with quality control as the latest technological development. 

This presentation will give an introduction to the approach of determining the required number of testing fans when conducting air tightness measurements of large buildings. From experience in testing practice and recording measurement results, we know that large buildings regularly achieve significantly better test results than required by German regulations. To share our experience, we will present these good test results to start a discussion as to which limits of air tightness in large buildings can be considered adequate. 

The manufactures tests of windows in Europe are executed in accordance with the CE-directive. Air- and water tightness testing are performed in accordance with EN 1026 and classified in accordance with EN12207. Air- and water leakage measurements are performed under laboratory conditions using a test chamber and accurately air- and water flow and pressure difference.

The Association for Air Tightness in Buildings (FLiB e.V.) offers air tightness testing teams the possibility to check their testing performance as well as that of their equipment. Round-robin tests allow the participants to conduct independent air-tightness tests in a building organized by the association.

During the BlowerDoor building test, it must be ensured that all building parts of the test building or the test section have air connection, and that the test object can be considered one single zone. This also applies to large buildings like office buildings, schools, indoor pools, etc. with several floors and winding floor plans. Overly tight airflow paths from the leakages to the measuring device prevent an even pressure distribution.

The round-robin test of Czech airtightness providers was organised in order to obtain information about the measurement equipment generally used and in order to compare the test results given by different technicians operating with different devices. All the participants measured the same building under very similar conditions. The preparation of the building before the measurement and the calculation of the building reference values were done by the organisers. All the test results were evaluated according to EN 13829.

The contribution informs about the foundation of a professional network of Czech airtightness test providers and gives basic information about the organisation and activities of this association.An idea of closer cooperation between Czech building airtightness test providers has existed for several years. (one outcome of such activities is e.g. a database of test results – see Novak (2009)).

The actual question is as follows: “Is the building envelope of the first passive house in China sufficiently airtight?” To determine air-tightness in China, a pressure differential test was to be conducted. First, a number of questions had to be answered. What building system is used and which materials are implemented? Who will conduct the measurement, according to which standard will it be conducted, and how will the measuring equipment be transported to the site? What are the customs regulations to be observed and what kind of problems could the authorities in the area pose?

The new Part 7 of the Thermal Insulation Standard DIN 4108 describes the permanent design of the airtight layer of heated or air-conditioned buildings. In the chapter on requirements, some terms have been redefined. However, the required values for the maximum air change rate are stipulated in the current EnEV (German Regulation on Energy Conservation). The planning chapter features many new sections concerning the planning task as well as some additional schematic diagrams. The materials chapter deals with the suitability and implementation of joints and connections.