State of the Art Multiple-Fan Airtightness Measurements

There is increasing recognition of the importance of quantifying the airtightness of large commercialand residential buildings. Often these tests must be performed with multiple fans and technicians,usually within a narrow time window. Despite the best preparations, surprises and interruptions areunfortunately the norm. It is therefore critical to streamline the hardware and software.Challenges to be overcome include time varying and spatially non-uniform envelope pressures andthe need to simultaneously capture multiple fan flow readings. It is also necessary to analyze theresults quickly enough to decide when testing is complete and whether the results meet the testrequirements.The solution described consists of several computer-controlled digital manometers accessed by asingle computer in real time. Fan speeds can be computer-controlled. The data and annotations arerecorded into a single time-series data file. The user can easily see large deviations in buildingpressures due to wind, door openings, etc and can then graphically create and edit "periods of record" (the data to be included in the test results). Within the software a standard log-log airtightnessregression is performed on total fan flow versus average building pressure. Other features areavailable for exporting data and exploring the data graphically.