English

This paper presents a numerical study of instationary three-dimensional flows. Three methods, a semi-implicit one and two explicit ones were compared and tested on typical flow configurations (lid driven cavity, natural convection and mixed convection in a cavity). These methods were then applied to a problem of ventilation in a paint-booth. The semi-implicit method proved to have a higher accuracy. The explicit method of the M.A.C. type turned out to be more advantageous in calculation time.

In order to reconsider the ventilation requirment in office environment and air environmental indices to determine it, field measurements were carried out. The amounts of outdoor air taken into air conditioning system were controlled in three levels and the concentrations of various indoor airpollutants were measured. It was found conclusively that 30 cubic meters per hour per person of intentionally introduced outdoor air was appropriate for ventilation requirement for offices and carbon dioxide was also appropriate as an index.

This paper gives a presentation of the current research being carried out at NSIB with the aim of exploring the effectiveness of ventilation systems in controlling contaminant levels. The key concepts used for quantifying the performance are; the age distribution of both air and contaminants. The air exchange effective- ness and the average ventilation efficiency are derived from the age distributions. Measurements of the performance of different ventilation s systems are given, expressed in terms of the key concepts above.

The relationship between the observed concentration of air pollutants at points within a building and the characteristics of the ventilation system is examined, and a basic set of analytical expressions showing these relationships is presented. The extension to large and complex systems is considered, and an example of the application of the equations to an actual air quality problem is given.

Effectiveness of ventilation as a major means of controlling indoor air quality was evaluated by correlating concentrations of gaseous (CO and CO2) and particulate (total) pollutants with two ventilation parameters. Pollutants are differently af

The tracer technique can be used in ventilation and contaminant spreading investigations. We have chosen sulphur hexafluoride. We have constructed aspecific instrumentation to perform indoor tests. All components are portable and battery operable. We use generators with remotely controlled flow, real-time chromatographs as analysers, continuous SF6 monitors and field-use calibrators. We have performed numerous tests, in the nuclear industry (Laboratories, reprocessing facilities and PWR), in conventional industries and in hospitals.

A multiple tracer gas method for following air movement in buildings has been developed and demonstrated at the Polytechnic of Central London. This paper describes the method and shows how it is being used to investigate: 1. the whole house inf

Tracer gas techniques, used for routine ventilation checks or trouble shooting are outlined with emphasis on their applicability in a variety of situations. 

This paper presents a method for a more accurate calculation of air exchange in the mechanical ventilation of industrial halls with uniformly distributed heat load. The method has been developed on the basis of finding the relation between the

As measurements are essential for performance assessment, models are essential for design. Both empirical and rational models are being developed for predicting the effectiveness of ventilation for acceptable indoor air quality. In this status report, models for contaminant generation rates, and dilution and removal control are introduced through a simple, one-compartment model.