English

Presents a review of the problem area relating to unintentional ventilation, with special reference to the significance of this phenomenon with regard to the heat balance of buildings. It also contains a list of research tasks which the authors consider to be urgent. Factors which affect unintentional ventilation are discussed, such as wind and temperature conditions outdoors, permeability of the climate envelope of buildings, flow conditions on rooms with known rates of air supply and known temperature conditions, air movements in a flat and in the entire building.

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.

Presents infiltration model whose input is: 1) air leakage under fan pressurisation and 2) natural indoor/outdoor pressure differences. Output is the house's natural infiltration rate. Describes tests of model on 6 houses in usa, 3 conventional houses in a mildclimate region and 3 energy-efficient houses in a cold winterregion. Obtains good agreement between infiltration rates measured using tracer gas and rates calculated from the model.

Describes investigations in California with a mobile laboratory designed specifically for studies of indoor air quality and energy use in buildings before and after energy conservation retrofits and in new buildings incorporating energy-efficient designs. Among parameters measured are infiltration rate, content of CO, CO2, NO, NO2 SO2, O3, formaldehyde, radon, etc. Results of initial phase of program indicate that concentrations of some air pollutants in the built environment are higher than outdoor levels and in some cases exceed recommended health and comfort criteria.

Heat load from passage of cold outside air to building interior is function of wind speed and outdoor air temperature. Analyses meteorological data to determine suitable design conditions for accurate assessment of infiltration heat losses. Terms multiple of wind speed and indoor-to-outdoor air temperature 'wind-temp number' using it as measure of infiltration heat loss caused by wind. Plots these numbers for range of outdoor air temperatures and wind directions.

Describes experimental method of determining air leakage characteristics of exterior walls of a building. Method involves pressurising the building with the supply air system and measuring flow rates of outside supply air and resultant pressure differentials across building enclosure. Uses results to obtain flow coefficient and exponent for exterior walls. Checks method by results of computer simulation of a building, finding good agreement.

Reports study of air infiltration through experimental windows installed in a normal office building. Air change rate was measured using carbon dioxide as a tracer gas. Pressure drop across window, wind velocity and direction were recorded . Finds that air leakage measured was generally quite different from that which could be calculated. Postulates reason for this is complex process caused by dynamically varying pressure differential across the window, flow occurring through window in both directions simultaneously and to particular experimental configuration used.

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.

Reports results of series of tests on 6 single-family houses to determine rates of overall leakage through windows, doors, walls and ceilings. Uses vane- axial fan to reduce pressures inside house and measure flowrate and resultant pressure differences across house enclosure. Purpose of tests was to assist in eliminating rates of air infiltration in houses.

Detailed analysis of actual space heating requirements shows a much higher consumption in mild weather than predicted. Attributes this mainly to casual window opening, which accounts for 30% of total energy used. This factor will be greater in well-insulated houses where ventilation loss is proportionately greater. Examination of motives for window opening suggests high humidity levels are most likely. The trend to man-made fibres in soft furnishings with low moisture storage capacity accentuates humidity problem.