German

Notes increasing concern with the quality of indoor air, allied with the desire to conserve energy by minimising ventilation rates. Examines on the basis of a literature search the sources of indoor air pollution and the characteristics of the pollutants. Pays particular attention to tobacco smoke and its deleterious effects on health. Discusses minimum ventilation rates for rooms in which people smoke. Points out that ventilation alone cannot ensure that the strictest criteria for room air quality are met with smoking.

Discusses the requirements of air supply installations in high-occupancy spaces. Describes the characteristics of different systems of air diffusion, illustrates them and their operation in diagrams and photographs and demonstrates the nature of the room air flows created by them. Lists and discusses the advantages and drawbacks of air introduction from chairs and desks, from pivoting nozzles in walls of galleries and from ceiling or floor diffusers.

Notes that with increasing air quality standards, requisite environmental protection cannot always be ensured with existing air handling installations in industrial halls. Presents methods of improving performance using devices to monitor pollutant levels and to give enhanced ventilation. Points to deficiencies still obtaining in these fields. Provides examples of new air quality evaluation methods and plant concepts, which have been tested in practice, to illustrate their the recommended approaches and their application.

Describes the network procedure for calculating the most energy-conserving and economical form of natural ventilation of a building. Provides application examples in the form of the determination of mass air flows through doors and windows and cracks in industrial work sheds. Provides the results of a calculation of crack ventilation in winter with mechanical ventilation with positive pressure, plus optimisation of air flow through a cooling bed for hot rolled steel sections.

Notes increasing complaints in Germany with the use of air conditioning and mechanical ventilation systems, despite them creating an indoor climate meeting the stipulations of German standard DIN 1946. The complaints are mainly of draughts, dry air, stale air and variable temperatures. Attributes most causes of complaint to the systems of air supply. Examines the drawbacks of various types of air supply system - dilution ventilation, window ventilation, displacement ventilation.

Notes reasons for reducing dust concentrations in rooms - allergic reaction to pollens and mould spores, etc., plus the fact that viruses and bacteria and some substances causing smells are often attached to dust particles.