A progressive comparison of the novel pulse and conventional steady state methods of measuring the airtightness of buildings

•Fan pressurisation and Pulse test results are compared in wider ranges of pressures.•Good agreement is achieved under a consistent preparation.•Impact of fan installation leakage to the leakage measurement is evaluated.•Installation leakage represents a significant proportion of the airtightness of highly airtight space. Differing from the steady fan pressurisation method (FP) that takes airtightness measurement at high pressures, the Pulse technique takes a dynamic approach and offers low-pressure measurements. Despite different measurement pressures, the interest for direct comparison between the results given by both methods remains strong in research and practice. When testing a typical dwelling, achieving a comparison in an overlapped pressure range comes with difficulties due to Pulse’s low-pressure measurement. In this paper, experimental investigations were performed in two independent studies to enable measurements over an overlapped pressure range under both outdoor and indoor environments. Results in the outdoor environment showed that the FP installation could account for a significant proportion of the air leakage of tested spaces in particular the ones with an airtight enclosure, thereby contributing to the deviation (42-60%) between both testing methods. Such deviation was reduced when sealing is applied around the FP frame. Results in the indoor environment where the impact of outdoor environmental conditions, installation and model difference was reduced showed that a better agreement (0.6-9.6%) was achieved in a range of leakage levels.