QMM032014

Over the recent years more effort has been given to air tightness of public buildings such as hospitals. The demand for well insulated buildings increases the importance for low infiltration air rates and thus the air tightness becomes more important. Besides, air infiltration is a quantitative way to put into requirements for the tenders to fulfill.  In this work we describe field measurement of air-tightness on site in early stage of production, as well as field measurement of a whole floor in a hospital building.

Infrared thermography is an interesting technique that is often used for qualitative assessment of the building envelope. The method allows to detect construction deficiencies e.g. thermal bridges, moisture problems, incomplete blown-in retrofit insulation of cavity walls, wind washing in insulation layers etc. in a very fast way. Another application is the use of infrared thermography in combination with pressurization tests  in order to detect air leakages through the building envelope.

Because of temperature-based uplift within the building and the impact of wind on the building, airtightness measurements of high buildings are especially challenging. Temperature differentials between the building interior and the exterior with particularly high buildings can lead to excessively high baseline pressure differentials on the building envelope while the impact of wind can cause their extreme fluctuation, both of which may have a negative effect on the measurement. 

In this paper we present a series of leakage tests on extremely airtight dwellings (ACH50 < 0.6 upon completion) in which the durability of the airtightness and the measurement uncertainty involved are assessed. In literature, repeatability and reproducibility issues have been discussed by several authors, along with influences of weather. It remains unclear, however, to what extent the available uncertainty intervals are relative or absolute.

This paper gives an overview of the work undertaken within CEN TC 156 WG 3 dealing with ductwork for ventilation in buildings.  

Mandatory building airtightness testing has come gradually into force in the UK, France, Ireland and Denmark. It is considered in many other European countries because of the increasing weight of the building leakage energy impact on the overall energy performance of low-energy buildings. Therefore, because of related legal and financial issues, the building airtightness testing protocol and reporting have become crucial issues to have confidence in the test results as well as the consistency between the measurement results and values used in the energy performance calculation method.

Since 1995 with the first edition of the GUM by Joint Committee Guide for Metrology, (JCGM) expression of uncertainty in measurement takes a large part in measurement activities. To be able to give a measurement result with a sound uncertainty expectation, different approaches exist that were covered in several linked documents depending of the available measurement model. In this presentation, we will give an overview of the main methods based on physical model and show that each available method addresses a corresponding model situation.