Ad Hoc Group 4 of Working Group 2 of CEN TC156 (Ventilation) was set up to put forward standardised techniques for estimating ventilation rates in dwellings. The purpose of the standard is to ensure that different people carrying out calculations with the same input data will obtain the same result. This will allow the use of these results in energy, heating load, IAQ or other calculations. The methods proposed use two different techniques, an explicit and an implicit one. The explicit one involves more approximations, but can be carried out with a hand calculator.
In the frame of the European standardization work, an ad hoc group of CEN TC 156, WG2 Mechanical and natural powered residential ventilation , is presently working out calculation methods for the determination of air flow rates for dwellings. A first draft standard has been prepared and is currently under revision by the working group and experts of the national CEN shadow committees. Since the draft with its annexes is rather comprehensive, this article summarizes only roughly the basic assumptions and the methods developed so far, without giving the definitions and equations in detail.