The distribution of wind pressure on a building envelope is governed by the size and shape of the structure and the turbulence characteristics of the wind. Observation of the mean wind pressures shows that surfaces are divided into pronounced zones of positive and negative pressure. The turbulence gives rise to fluctuating pressure components of appreciable magnitude. This fact changes the prerequisites of the ventilation for a given volume. The pressure in the cavity behind the facade materials depends on the external pressures over the facade.

During the past decade a multitude of diagnostic procedures associated with the evaluation of air infiltration and air leakage sites have been developed. The spirit of international cooperation and exchange of ideas within the AIC-AIVC conferences has greatly facilitated the adoption and use of these measurement techniques in the countries participating in Annex V. But wide application of such diagnostic methods are not limited to air infiltration alone.

A method is being developed for visualization of air flow with application to the indoor problems of heating, ventilating and air conditioning. Photographic images of the soap bubbles seeded in space reveal features of the flow which can be quantified by the digitizing operations. Determination of the velocity vector field from the experimentally recorded images is possible.

Moisture and mould in buildings have become fairly common problems in Italy, particularly since regulations aimed at energy conservation have been enforced in the seventies. Results of a case study conducted within IEA Annex XIV are presented in this paper. Two flats belonging to the same building (one with and the other without moisture problems) have been monitored during the winter 1987-88. Indoor temperature and air humidity, wall surface temperature and weather parameters were recorded for several weeks using two automatic data loggers.

Rising moisture from the ground has caused quite a lot of damage on foundations of Swedish buildings. It is in some constructions possible to prevent this by mechanical ventilation below the floor or below the concrete slab. This paper will present a model for coupled air flow and heat conduction for mechanically ventilated foundations. The presented model uses analytical expressions for the air flow in an air-permeable layer below a rectangular building. Analytical double-periodic functions of elliptic type are used.

The paper describes the development in airflow simulations in rooms. The research is, as other areas of flow research, influenced by the decreasing cost of computation which seems to indicate an increased use of airflow simulation in the coming years. It is shown that velocity and temperature distribution can be predicted in small rooms of simple geometry as well as in large areas with a complicated geometry, such as theatres, atriums and covered shopping centres.

In order to be validated, the computer programs simulating the air flows in multizone buildings need several measured data sets to be compared with. Such a set was measured on the LESO, a mid-sized administrative building. This set contains: a) The permeability coefficients (C,n) of the building obtained by guarded zone pressurization b) Pressure coefficients Cp measured in windtunnel and on the real building c) Tracer gas air flows measurements d) Corresponding weather data for two periods of 10 days on the non inhabited building.

It is particularly important to be aware of the air flow pattern in a building when determining indoor air quality problems or calculating space conditioning loads for energy consumption. Correct sizing of space conditioning equipment is also dependent upon accurate air flow information. A number of infiltration models have been developed to calculate infiltration-related energy losses and the resulting air flow distribution in both single-zone and multizone buildings.

This paper presents and evaluates a new method, based upon tracer gas techniques, for determining interzonal airflows and effective volumes in a multizone enclosure. Presently used tracer gas techniques have a number of drawbacks including the need for multiple tracers when analyzing a multizone structure. Also, traditional techniques cannot be used to independently determine flows and volumes in the multizone case. The method described in this paper eliminates some of the problems introduced by multiple tracers and allows the independent determination of both flows and volumes.

This paper describes a set of experiments conducted in a three bedroom house in order to identify the leakage distribution of the building and the air flow rate through the on-purpose designed opening of the interior doors. Starting from the depressurization test in every zone, we were unable to track all the flow equation of every specific identified connection. We therefore propose to characterize the leakage between two zones by a unique general connection. Its flow behavior (K,n) is determined by an optmization under constraints of the results of the various tests.