Practical measurement has shown that gasoil and candle flames provide constant tracer gas sources. Suggests their use for meaSuring ventilation. suggests application in temporary dwellings such as caravans, using candle as simulated "people" consuming oxygen and producing heat and carbon dioxide. Describes measurement methods using natural decay exponential equation. Graph illustrates sequence when air change rate fulfills requirements in swedish building code 1975 of 0.5 change/hour.
Outlines parameters governing air infiltration. Discusses problem areas of house to house comparisons of air leakage. Deals primarily with tracer gas procedure as compared with pressurisation/depressurisation approach. Describes testing in townhouses of recent construction as well as in a number of older homes of varied design. Uses roof-top laboratory test chamber to examine relations between wind effects, buoyancy effects and building openings and how they effect air infiltration. Uses results to clarify evaluation of air infiltration.
Describes how in 1960-62 National Research Council of Canada conducted air infiltration measurements on 2 single-storey houses using helium as a tracer gas, followed in 1967-68 by measurement of air leakage characteristics using house pressurisation technique. Describes procedure developed from these tests for calculating infiltration rates. Gives equations for calculating infiltration due to stack effect and that due to wind action. Gives equation for combined effect.
Reports measurements of ventilation rate in specially designed low energy office building. Air change rates were measured using sulphur hexafluoride as a tracer gas and air samples were analyzed for carbon dioxide. Gives tables of results. Discusses analysis of ventilation from CO2 data. Concludes that most of the spaces in the building were operating at or above recommended levels.
Notes principle of air change rate measurement using natural growth exponential equation to measure concentration of tracer gas. Experience shows that period required for satisfactory measurement is often periodicity of air change rate. Diagram relates linear and logarithmic scales used in air change equation. Describes use of pre-programmed gas analysis equipment allowing extrapolation to forecast results. Uses microprocessor for evaluation. Also discusses importance of instrument calibration.
After discussing briefly the principles of natural ventilation, goes on to describe tracer gas techniques, air movement measurements, and various model techniques including analogues. Advantages and disadvantages of each method are indicated, andtheir suitability for particular applications.
Using nitrous oxide as a tracer, the author made 390 measurements of ventilation rates in seven closed rooms of six houses, in Melbourne, Australia. Half of the observations were taken when the wall ventilators were sealed, in order to explore their influence on room ventilation. Results for each room, grouped in ranges of wind direction and according to whether ventilators were open or closed, are shown as regression curveson plots of ventilation rate against wind speed. The ventilators are shown to have only a slight effect on ventilation.
Treats measurements of air infiltration rate in 2 mobile homes - one treated with caulking, the other with continuous sheathing board - over entire heating and cooling season. Concentrates on summertime data. Summarises results in graphs and tables. Analyses results to find general parabolic dependence on wind and linear dependence on temperature difference. In addition data exhibit marked reduction of infiltration attributed to use of continous sheathing board.
Describes measurements of airtightness and ventilation in prefabricated 'modulent' houses, 25 single-storey with habitable lofts and 8 single-storey, all with mechanical extract systems. Measurements used pressure method and tracer gas in houses with different airtightness, types of window, windproofing and facing materials. Possibility of presetting ventilation terminals and fans to achieve recommended airflows was investigated. Treatsrelationship between wind, temperature and airtightness. Notes number of shortcomings in ventilation system discovered during investigation.
Reports measurements in title. House was contained in environmental chamber with control over inside and outside temperature with essentially no wind velocity. Observes familiar correlation between inside-outside temperature difference andinfiltration rate, and effect of sealing doors and ducts underconditions of negligible wind velocity. Compares different methods of collecting air samples for analysis and compares SF6 measurements with air exchange rates imposed on the house by means of a centrifugal blower.
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