Natural ventilation of mill buildings is a process which is complicated by several factors such as external wind pressure and local distribution of heat sources. Describes theoretical and small-scale physical modelling techniques for predicting ventilation rates. The theoretical approach using a computer for the numerical aspects allows rapid and reliable assessment of the ventilation rates for very complicated building designs under any appropriate wind conditions.
Reviews technical progress being made in the industrial ventilation field by different investigators through out the world. Subjects reviewed and updated include natural ventilation, local exhaust ventilation, specialised ventilation techniques (dilution, air jets, air curtains, recirculation of filtered air, tracers for ventilation studies) and mine ventilation. Presents typical applications of the new technology to solving industrial ventilation problems, and identifies areas requiring further research and development.
Identifies alternative methods available to control indoor air pollutant exposures. Describes the performance characteristics of ventilation systems and of air cleaning devices used in mixed modes for ventilation of occupied spaces. Reviews models for predicting effectiveness of several alternative modes, with field trial validation results cited where available. Briefly reviews previous confined-space studies as points of departure for consideration of necessary air quality, ventilation and air cleaning.
Treats the relation between transmission heat loss and ventilation heat loss of buildings. Notes normal methods of fresh air ventilation of dwellings and problems arising with buildings being made increasingly airtight so that air infiltration is greatly reduced with consequent condensation and lack of maintenance of minimum hygiene standards. Illustrates and discusses possible future ventilation systems including mechanical supply and extract ventilation systems incorporating heat recovery systems. Illustrates several alternatives diagramatically.
Reports on an extension of the metabolic CO2 method for ventilation measurement to a naturally ventilated room having air flow connections with other internal spaces as well as the outside. Uses an infra-red gas analyser to monitor CO2 concentrations in the fresh air outside and also within theroom, the corridor and the ceiling space. An automatic unit switches the analyser between 6 sampling points. Comparison of the data with results from SF6 tracer gas decay methods gives close agreement.
Examines airflow in the Glowworm cave of New Zealand using conventional methods together with experimental procedures using SF6 and CCL2F2 tracer gases. Results show that the rate and direction of airflow are a direct response to a thermally
Uses the SEGAS "Autovent" constant concentration apparatus to measure the fresh air entering and the local ventilation rate in each cell of amulti-celled dwelling with both natural and mechanical extract ventilation. Measures fresh air entry into each cell using tracer gas constant concentration and decay techniques. Conducts decay tests without artificial mixing, and interprets them by computing the area under the decay curve to obtain local ventilation rates. Compares the 2 measurements, giving the ventilation efficiency of each cell and an idea of air quality in each room of the house.
Examines the possibilities of achieving energy-efficient ventilation systems in naturally ventilated homes (which include the use of intermittent extract fans in individual rooms). Discusses factors affecting energy efficiency. Treats general design requirements for mechanical and natural ventilation systems. Discusses the characteristics of natural ventilation systems, including leakage, weather and window opening. Compares natural and mechanical systems. Provides suggestions for natural ventilation design.