When a fume cupboard is placed in a room with a ventilation duct, the air movement inside and around the fume cupboard is fully three-dimensional turbulent flow. However, in order to understand the fluid flow away from the fume cupboard a much simpler model can be used. This leads to a steady 20 model, with the computational domain including only the sash of the fume cupboard, the room and the entrance into the ventilation duct. In this paper we have used both the k-E turbulence model and the wall function technique to calculate the steady 20 turbulent fluid flow.

Effective ventilation systems for a factory where various kinds of contaminant are discharged from many point sources are investigated in this study. Two ventilation systems are examined by scale model experiment using tracer gas. One system supplies fresh air and exhausts indoor air through the ceiling; the other has the inlet in the floor and outlet in the ceiling. Each system has a hanging wall installed at the ceiling, a device for immediate removal of the contaminant before it diffuses into the whole space.

This article describes a new and more efficient Vortex Air Distribution system for a soda recovery boiler house. Essentially th.e technology utilises directional air supply of up to 150 m3/s to compensate for beat gains of up to 2000 kW. Issues addressed include all stages of the design process from the Computational Fluid Dynamic (CFO) experiment and scale mock-up tests in the laboratory conditions to the field measurements after the system had been installed. The supply air is distributed into the building through specially designed air terminals.

Determination of the distribution of contaminant particles within zones becomes of great interest, with the increasing concern for indoor air quality. In order to improve the indoor air quality in a realistic building, the air movement and contaminant transport in a partitioned enclosure with ventilation have been studied numerically and experimentally. A three-dimensional analysis of air movement, temperature distribution and contaminant particle transport is made to investigate airflow patterns and deposition of contaminant particle in a partitioned enclosure.

Future information age technology will demand cleaner and more cleanrooms for the manufacture, assembly and repair of electronic components. Many special processes can be very sensitive to trace contaminants which are not removed by conventional air conditioning, filtering and distribution. High efficiency particulate air filters, high velocity streamline air flows, relatively dry air, clean ducts and plenums, cooling, noise reduction and perhaps disinfection are needed.

The occupants of buildings are exposed to a range of aerosol contaminants, of both indoor and outdoor origin; at present, filtered mechanical ventilation is the only effective means of airborne particulate control in polluted urban areas. Significant energy costs may be incurred, however, through the large pressure drops associated with membrane filtration. An alternative to filtration might be the enhancement of aerosol deposition on a protruding surface which is parallel to the incoming airflow direction, but which does not significantly retard the airflow.

Microbial monitoring of the indoor environment can be performed in several ways and with the aid of different techniques. Knowing the limitations of the chosen system is of vital importance for the correct evaluation and interpretation of the results. The number of Colony Forming Units (CFU) detected by one method can not be directly compared with results from another method. The paper presents an evaluation of commonly used instruments for the collection and counting of airborne viable particles.

Several studies have shown that the lowest concentrations of contamination in operating theatres are achieved by using fabric covered laminar airflow systems. These systems are distinguished due to the low turbulence intensities in the protective areas. An examination in a special designed test facility was done to get further information about the relation between the turbulence intensity and airborne contaminations. In a first stage the dispersion of airborne contaminations was examined.

A new experimental set-up to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust related problems in rooms, there is a need for better understanding of the mechanism of dust deposition and resuspension.