By measuring the pressure decline in a pressurized air volume from which air is leaking it is possible to determine the air leakage rate as a function of the pressure difference. The leakage rate is proportional to the time derivative of the pressure. The formula, which is quite simple, accounts for temperature change of the air and volume change of the chamber. The derivation of the equation relating air leakage to pressure drop is described. Initial tests of the method have been performed and the derived equation shows good agreement with air leakage rates obtained by theoretical as well as standard steady-state methods.
Mattsson, B. and Claesson, J. (2005). A Transient Method for Air Infiltration Measurements of Building Envelope Components, In: Proceedings of the 7th Symposium on Building Physics in the Nordic Countries, Reykjavik , 13—15 June.
9.
Mattsson, B. and Claesson, J. (2006). Exploration of a Transient Method for Measurements of Air Tightness, In: Proceedings of the Third International Building Physics Conference, Concordia University, Montreal, Canada, 27—31 August.
