English

Wind pressure measurements made over a 4 years period on a 34-storey building in downtown Montreal were used to obtain data for checking and improving wind tunnel techniques of modelling flow characteristics of wind and aerodynamic behaviour of buildings. Specifies the major problems involved in making field measurements and in comparing them with wind tunnel measurements. Comparisons with model measurements are made. Examples have been found of excellent agreements, but for some wind directions the comparisons gave unsatisfactory correlation.

Discusses current knowledge concerning wind-induced ventilation in buildings. states major difficulty in estimating ventilation and infiltration rates in a building is ignorance of wind pressure distributions around structures. Examines properties of wind with special reference to mean velocity profiles, characteristics of turbulence and wind energy spectrum. Reviews internal and external pressure distributions on an isolated building. Studies effect of grouping of buildings on pressure distribution around a house by considering results of wind tunnel tests.

Reports a theoretical study of natural ventilation made jointly by HVRA (UK) and Institute for Public Health Engineering TNO (Netherlands). Uses analogue and digital computers, and results so derived were used to produce a design method suitable for rapid assessment of the natural ventilation of projected buildings. Shows this method to be quicker, cheaper, and more accurate than the crack method (measured leakage at windows and doors) or the air change method.

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.

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.