Calculation methods for the determination of air flow rates in dwellings.

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. The implicit one requires the use of a computer. This paper explains the methods used, justifies the approximations made and gives examples of the use of the explicit method. These show that the explicit method gives results in good, but not perfect, agreement with experiment, and also that the method is simple to use.