Presents a review of the main methods used for the study of air movement. Includes sections on physical modelling (wind tunnel modelling etc), analogue (water and electrical) models of air movement, mathematical models and digital computer analogues, and full scale investigations including pressurization andtracer gas techniques.
Describes method which permits long term tracer gas measurements in several separate rooms simultaneously. The method employs a fully automated constant concentration system developed at the laboratory for building physics at the Swedish Institute for Materials Testing. Describes measurement principles andpractice.
Air change rate is often reported as a single number, with no attention paid to different values of air change rate in different zones of a building. This may affect air quality evaluation as there may be undetected zones where air change rate is too small, resulting in localized pollutant concentrations. Describes a multi-point tracer gas technique used to quantify air change ratein different zones of various residential buildings. Defines and calculates zonal ventilation efficiency terms, and proposes a criterion for analysis of the results for indoor air quality evaluation.
Investigates the reliability of the single-room infiltration model used in the computer program ENCORE. Compares calculated air change rates with tracer gas (N2O) measurements in 25 identical one and a half storey detached houses. Describes the infiltration model, the parameters and some results. Thecomparison shows good correlation at low wind speeds (< 3m/sec) but the model's values at higher wind speeds are too high.
Presents the underlying theoretical basis for measuring air flows in complex, multi-cellular buildings and by reviewing the existing experimental procedures which enables the carrying out of these measurements. Shows that inter-cell air flows can be determined only by generating N sets of tracer gas conservation equations, where N is the number of cells. Describes 3 systems being designed to carry out multi-cell ventilation measurements< 1. "grab sampling"< 2. multiple tracer measurements< 3. measuring averaged air change rates over long periods.
Describes a project aimed at developing a method of measuring air infiltration rates in large single cell enclosures and buildings, and of using the method to collect data on actual infiltration rates. Makes a brief survey of existing and novel methods of measuring air infiltration rates. Identifies 2 methods which merit further consideration - the use of methane as a tracer gas,measuring its concentration with an infrared laser technique; and the use of ethanol vapour as a tracer gas, measuring its concentration with a fuel cell detector.
Gives a summary of the work in testing of different energy-saving retrofits performed in dwellings in Sweden. The report is based on work done at the Swedish National Testing Institute and the National Swedish Institute for Building Research carried out during the winter 1979-80. Thermography methods, pressure test method, tracer gas measurements and heat flow measurements wereused in 91 houses, which were retrofitted. Describes different test methods and discusses results of measurements.
Briefly overviews some of the available instrumentation and techniques that could be used by the home-owner, or professional auditor to evaluate energy use in houses. Includes descriptions of the "blower door" method for evaluating air leakage, and some tracer gas techniques for measuring air infiltration.
Describes a simple, inexpensive sampling technique for infiltration measurement using SF6 tracer gas. Uses pre-evacuated blood collecting test tubes with rubber stoppers for sampling. This is controlled by a micro-processor driven automatic sampler, which drives a hypodermic needle through the rubber stopper to fill the tube with an air sample. Analyzes samples using a gas chromatograph. Releases SF6 at ground level in a high-rise cold store and collects samples of air at different heights to see if stratification is present.
Measures air exchange across open cold store doors using an anemometer and by tracer decay methods. Anemometer results show that an empirical factor of 0.68 should be applied to the predictive equation by Tamm. Observes a further reduction in air change rate (about 47% reduction) due to imperfect mixing of the air. Air curtains reduce infiltration by about 75-80% and plastic curtains by approx. 93%. Forklift traffic and internal circulation fans also affect air change rate.
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