A practical review of alternatives to the steady pressurisation method for determining building airtightness

Abstract

As an important indicator of construction quality and envelope integrity of buildings, airtightness is responsible for a considerable amount of energy losses associated with infiltration. It is crucial to understand building airtightness during construction and retrofitting to achieve a suitable envelope airtightness which is essential for obtaining a desirable building energy efficiency, durability and indoor environment. As a convenient means of measurement, the current steady pressurisation method has long been accepted as a standard testing method for measuring building airtightness. It offers an intuitive and robust approach for measuring building airtightness and performing building diagnostics. However, it also has some shortcomings that are mainly related to its high pressure measurement, requirement for skilful operation, long test duration and change to the building envelope. Efforts have been made by manufacturers and researchers to further improve its accuracy and practicality with much progress achieved. Work has also been done to develop alternative methods that can overcome some of the issues. This paper provides a practical review on the incumbent methodology and efforts that have been made over the past decades in research and development of other methods to achieve a similar purpose. It compares them in relation to aspects that are considered important in achieving an accurate, quick and practical measurement of building airtightness and the finding shows other methods such as acoustic and unsteady technique have their own advantages over the steady pressurisation method but also add some of their own restrictions, which therefore makes them suited for different applications.

Estimation of the infiltration rate of UK homes with the divide-by-20 rule and its comparison with site measurements

“…Due to being disruptive, time consuming and complex to operate, tracer gas based methods for measuring air infiltration are usually substituted with a measurement of building airtightness, which is then used to estimate the infiltration rate of the test building in conjunction with a leakage-infiltration relationship and sometimes environmental and terrain conditions. Although a number of airtightness testing methods are in existence such as acoustic [5,6,7] and unsteady pressurisation technique [8,9,10,11,12,13,14,15,16], the blower door is a convenient and reliable means for measuring building airtightness that has been widely adopted as the standard testing method in building regulations and voluntary standards. The measurement of building airtightness has become a regulatory requirement in many countries due to its impact to the building energy efficiency, indoor air quality and building durability.…”

Numerical and experimental validations of the theoretical basis for a nozzle based pulse technique for determining building airtightness

“…It is also desirable to test the airtightness of a building at lower pressure differentials, such that the flow through the envelope will mimic that of a building under ambient pressures. Such factors have provided the research motivation to seek for alternative methods to overcome some of the issues shown in the steady pressurisation method [36].…”

On the power law and quadratic forms for representing the leakage-pressure relationship – Case studies of sheltered chambers

“…The term 'air leakage', another way of quantifying airtightness, has often been used to describe the integrity of the building envelope. It fundamentally determines the building infiltration rate, which is responsible for a significant amount of energy losses during heating or cooling the building [2,3,4,5,6,7,8,9,10,11,12]. In the long term, it also affects the indoor air quality and building durability [13,14].…”