Discusses the mechanisms available for "single-sided" ventilation - ie when ventilation is achieved by the exchange of air through windows on one side of a space rather than by cross-ventilation. Describes a simple approach to its prediction based upon a combination of theoretical modelling, wind tunnel testing and tracer gas measurements made in full-scale buildings. Describes wind tunnel and full scale measurements which show the effect of degree of opening, window type and combinations of windows on the magnitude of ventilation rate.
Describes the results of a series of observations of window opening by occupants of 200 small offices in 5 buildings. Shows a high degree of association between the number of windows open and weather-related parameters. Estimated ventilation rates based upon the proportion of windows open, indicate levels substantially in excess of those required for indoor quality control, for a large part of the heating season.
Describes airing habits based on observation of windows of 50000 rooms in terraced housing and blocks of flats. Compares the results with observations in other countries. Derives an expression giving the fraction of indoor-outdoor temperature difference. Calculates from this information the average energy losses in Sweden due to airing.
Describes air leakage and tracer gas (SF6) measurements made in 42 Scottish houses. Finds that leakage in the "test" (better insulated) houses are on average 10% higher than that in the "control" houses. About 40% of the total leakage rate (at a pressure difference of 50 Pa) flows into houses through thefloor boards and the air-bricks under the crawl spaces. Tracer gas measurements indicate that average leakage rates with closed windows lie between 0.52-1.65 air changes per hour. Opening a window can increase the number of air changes by a factor of 2 to 5.
Examines by means of analytically calculable borderline cases the relative merits of continuous window ventilation or intermittent opening of windows. Illustrates the results relating to carbon dioxide content of the rooms ingraphs and discusses them. Findings depend strongly on the hygiene assumptions by which they are judged (identical maximum or identical mean CO2 concentrations or the identical mean air flow rate).
Describes a window opening survey concerned with identifying the objective correlates of window opening. Finds that the variation between households in terms of their total daily window opening is greater than that within households. Householders may adopt consistent window opening patterns. Hypothesises that although window opening is primarily a function of external air temperature, relative humidity and windspeed are influential at high values.
Outlines ventilation needs to show that odour dilution and moisture control are the major winter factors. Detailed studies on 24 well insulated houses show that window opening habits are clearly linked to outdoor temperature, more windows being opened in milder weather.< Shows from energy input analysis that space heating only provides a quarter of the total heat, the remainder coming from casual sources. Analysis of energy loss suggests that a third of the losses are attributable to ventilation, the remainder through the building fabric.
Describes the measurement of infiltration and air change rates in one flat in an apartment block containing 24 flats. Gives the general principles of the pressurization method and tracer gas method for measuring air change rate and infiltration rate. In this situation uses N2O as the tracer gas and measures concentrations with an infra-red gas analyser. Measures the effects of opening and sealing windows, and of closing internal doors on the air change rate and air movement in the flat.
Reports TNO-IMG research into ventilation of houses including the influence of cracks, open windows, weather conditions, occupants' behaviour, pollutants and guidelines. Lists conclusions such as an opened window renews the room air within half an hour. 40% of the occupants open windows for too long, 27%ventilate insufficiently, 25% of the dwellings are air tight, 75% leaky. Ventilation occurs partially through shafts (30%) and cracks (60%).Ventilation rates differ considerably between the rooms in a house.Ventilation ducts should have an exhaust function.
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