Tightness measurements of buildings and location of air leaks are performed both in new construction and renovation sites, if desired, to determine the airtightness of the structures and the location of possible leak points. Indeed, more attention is being paid to the airtightness of structures today, and for example, tightness measurements have become more common due to stricter energy efficiency requirements.

 

TIGHTNESS MEASUREMENT AND AIR LEAKAGE NUMBER q50

 

The tightness measurement determines the air leakage numbers n50 and q50 of the building envelope, of which the currently used q50 figure describes how much average leakage air flow occurs per hour at a pressure difference of 50 Pascals per building envelope area. The measurement is carried out using modern measurement methods and can be combined with a thermal camera air leak detection if desired.

 

If a lower end air leakage rate than the reference value 4.0 has been used as the design value in the energy certificate for the building permit phase, the tightness of the building must in principle be verified by tightness measurement.

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AIR LEAKING

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When possible air leaks are suspected, the tightness of the structures can be examined with, for example, marker smoke, thermal camera air leak detection or the tracer test method. When using signal smoke, observation takes place organoleptically by following the movements and routes of the signal smoke. The characteristic smoke test can also be used to evaluate, for example, the operation of ventilation.

 

In thermal camera air leak detection, the study is performed under either in-use or high-pressure vacuum, and can be used to assess the locations of potential air leakage routes as well as the intensity of air leakage. A report is always prepared on the measurement, describing the findings in writing and with light and heat images.

 

In tracer experiments, tracer gas is fed into the structures, after which gas migration is detected by a separate tracer analyzer. Prior to and during the tracer gas supply, the vacuum in the building shall be verified so that the direction of gas flow to the indoor air of the building remains; if necessary, the building is evacuated for the duration of the test. Tracer tests are well suited to, among other things, a situation where it is desired to determine whether there are air connections to indoor air from an identified damage area or, for example, from the soil. Tracer tests are also typically used as a quality control method for sealing repairs