BADA

From the beginning of year 2007 the buildings in Finland must have energy efficiency calculations, which requirements are now part of Building Codes, based on European Performance of Buildings Directive. According the renewed code, being into the force from July 2012, air tightness number q50 cannot be more than 4 m3/ (h*m2). Better air tightness can be shown by measurements. The air infiltration must be calculated in compensation calculations based on air tightness number 2.0 m3/ (h*m2). The energy efficiency requirements caused an immediate response in the building sector.

There are often practical limitations to measure the airtightness of a multifamily building as a whole as described in EN 13829. The building may be too large; the floors may not be connected with an internal airflow path; or there may be large leaks in the stairway.

A building was tested the equivalent of over 1,000,000 times under windy conditions where each test satisfied the conditions of ASTM, CGSB, ISO, EN, ATTMA and USACE testing standards in every respect. The air flow measurements made at lower reference pressures, such as 4 and 10 Pa, varied over a wide range of +87% to -45% from the average, while the results at 50 Pa varied 15% from the average.

The air tightness of building has been a serious problem over the last 30 years. In 1979 the international Air Infiltration Centre (AIC) was erected within the International Energy Agency (IEA) platform. Infiltration of cold air into buildings needs to be heated to reach to a comfortable indoor climate. But the energy penalty due to that should be minimized. The AIC (later AIVC) had as one of their tasks to find solutions for good air tight buildings and to promote the knowledge about building construction to reach acceptable level of air tightness of buildings.

As building insulation level increases, the coupling of ventilation systems with building enveloppe airtightness becomes an important issue in order to improve buildings energy performances. A building ventilation model can be built on a set of resistances and generators in order to handle infiltration, natural ventilation as well as fan driven air flows. The model is able to assess the indoor air humidity level and the building energy balance.

When conducting airtightness tests of buildings, you must ensure that all building parts to be measured have air connection, so that the test object can be considered as one single zone. This also applies to large buildings like office buildings, schools, old people homes, indoor pools, etc. with several floors and rambling floor plans. Openings that are too small for a constant air flow from the leakages to the measuring device can prevent an even pressure distribution.

The issue of the uncertainty of building airtightness measurements has built up a greater importance since this topic was introduced in many regulations regarding the energy performance of buildings. Different studies have contributed to the evaluation of the uncertainty but the question is still incompletely solved in practice.
To contribute to the determination of the repeatability and reproducibility of these measurements in practice, the Belgian Building Research Institute organized interlaboratory tests with 10 other laboratories.

The 2012 French thermal regulation will include a minimum requirement for residential buildings envelope airtightness, with two options to justify its treatment: a) measurement at commissioning or b) adoption of an approved quality management approach. This paper describes the qualification process for air-tightness measurement authorized technicians when their results are to be used in the EP-calculation method. Our analyses underline the importance of the qualification process to ensure homogeneous measurement practice among technicians.

In 2002 the Association for Air Tightness in Buildings (FLiB e. V.) established a certification procedure for airtightness testers in Germany. As airtightness tests are part of national implementation of EPBD but no qualification requirements for testers are defined FLiB e. V. took the lead and defined a procedure.

Origins of toxic gas clouds may be diverse, including accidental releases due to industry or to hazardous materials transportation, or biological or chemical attacks. A protection to such a phenomenon consists in taking advantage of the protection offered by buildings against airborne pollutants. In this event, people can shelter in a building and wait until the toxic plume has gone.