The aim was to develop a simple dynamic model for predicting air exchange caused by short time single-sided ventilation and necessary window opening time in classrooms. Tracer gas measurements have been made in a full-scale room. The comparison indicates that the model can be used when rough estimates of air exchange are of interest.

In dwellings ventilated by extract ventilation there are common complaints of cold draught caused by the supply air entering the room through openings close to the windows. This paper reports on studies of unconventional ways to distribute the supply air in order to minimise the risk of such problems. Experiments have been done where the supply air device is located in the hall of an apartment. The ventilation efficiency in the rooms adjacent to the hall has been studied with open and closed doors. The behaviour of gravity currents has also been studied in scale models.

Symmetry is not a sufficient condition for the design of a ventilated room to generate two-dimensional airflow. Three-dimensional effects were observed in a symmetrically designed 3m x 5m x 8.5m test mom having a 0.019m slot inlet opening height under the ceiling in the one end wall. The ceiling jet velocity profile measured in the symmetric plane agreed well with the jet models for two-dimensional !low, but large differences were found out of the symmetric plane.

The flow in a ventilated room will not always be a fully developed turbulent flow. Reduced air change rates owing to energy considerations and the application of natural ventilation with openings in the outer wall will give room air movements with low turbulence effects. This paper discusses the isothermal low Reynolds number flow from a slot inlet in the end wall of the room. The experiments are made on the scale of I to 5. Measurements indicate a low Reynolds number effect in the wall jet flow.

The protection of non-smoking persons against cigarette smoke is a very popular subject. In Germany the ,pro' and , contra' of non-smoking regulations especially in public accessible areas like restaurants, train stations or in governmental buildings is discussed in a more and more controversial way. Especially the discussion about passive smoking and negative health effects through passive smoking lead to the demand of an effective protection of nonsmokers.

This project covered 16 aircrafts including both smoking and non-smoking flights from June 1996 to August 1997. The parameters concerned were carbon dioxide (C02), humidity, temperature, carbon monoxide (CO), ozone (03), bacteria, fungus, and respirable suspended particulate (RSP). Compared with the Federal Aviation Administration (FAA) standard, C02, CO and ozone levels on all flights were within such standards. Peak levels of C02 and particulate were observed during both boarding and deboarding periods.

This study investigated the sources and concentrations of volatile organic compounds (VOCs) including formaldehyde in the air of a new office and conference centre building. The building is naturally ventilated, and was designed to demonstrate a number of innovative approaches to environmental design. Occupant surveys have shown a high level of occupant satisfaction with the indoor environment.

Ventilation is increasingly a subject of concern due to its relation with health and energy loss. Environmental pollution and global warming demands energy conservation and a Airtight structures are being built to reduce the energy losses due to infiltration. Reduced air change rates may lead to accumulation of C02 and other toxic pollutants to undesirable levels. In view of such concerns tests are carried out here to study the influence of ventilation on indoor air quality and thermal conditions in a naturally ventilated building.

This paper presents the difference in the air quality between that perceived by the occupants (breathing zone) and that in the occupied zone as a whole. An environmental chamber with displacement ventilation system has been used to carry out the measurements with the presence of a heated mannequin and other heat sources. Measurements of the age of air distribution, the air exchange index and the ventilation effectiveness were carried out at different points in the chamber for different room loads.

This paper is based on a dual approach (experimental and numerical) in order to predict the indoor air quality for small ventilated enclosures. The experimental part employs a ventilated test room and a tracer gas technique (constant method as gas injection) to estimate the diffusion of a pollutant. The gas used is the sulphur hexafluoride (F6S). The numerical approach is a CFD simulation, adding a convection - diffusion equation (to determine the local mass fraction of the pollutant) to the equations normally used to solve a turbulent flow.