Building airtightness tests have become very common in several countries, either to comply with minimum requirements of regulations or programmes, or to justify input values in calculation methods. With more widespread use it has become increasingly important to understand and quantify the reliability of these tests.
There are four key sources of uncertainty in airtightness testing: measurement devices (accuracy and precision); calculation assumptions (e.g., reference pressure, regression analysis method); external conditions (impact of wind and stack effect); and human factors, such as consistent test apparatus installation.
While competent tester schemes and independent checking procedures show potential to contain errors due to human factors, there have been extensive yet inconclusive debates about how the building pressurisation test standard ISO 9972 should address other sources of uncertainties. As a result, no change has been made to address uncertainty since the last version of the standard which was published in September 2015.
Another issue is with limitations on allowable test conditions. With the present ISO standard, the zero-flow pressure shall not exceed 5 Pa for the test to be valid. Consequently, in moderately windy conditions, it may be impossible to perform a pressurisation test in accordance with the standard, even if an uncertainty analysis would show small test errors. On the contrary, the complexity of the wind impact during a test might lead to situations for which the 5 Pa requirements will be met, whereas the wind will induce an important error on the result.
This paper aims at:
- Presenting and discussing the calculation method of standard ISO 9972 regarding the uncertainty induced by wind.
- Gathering published knowledge and determining what further research is needed on the quantification of the wind impact on airtightness tests results. This includes numerical simulations, laboratory and on-site measurements studies.
- Giving guidance for minimizing and better estimating the wind impact on airtightness tests results.