English

Describes the ventilation of buildings by analogy with electric circuits and derives expressions for ventilation with and without flow through ducts in the roof. Finds that in general ventilation rate will vary linearly with wind velocity. Considers the effect of shelter belts on wind velocity and derives expression for sheltered ventilation rate. Suggests that eddy motion caused by shelters may be important. Gives measurements made on models in wind tunnels to show the affect on wind pressure of sheltering buildings at various distances.

Describes measurements made of wind speed and direction and pressure differences across the exterior walls of two multi-storey buildings in Montreal. Regression coefficients are obtained and show better correlation for higher levels than forlower ones and for the taller building "A" than building "B", indicating that shielding by adjacent buildings has an important effect. The variation in wind velocity between the site and a meteorological station was recorded.

Describes a method of analysing the stack effect on a multi-storey building. The building is divided into zones and a computer programme calculates air-flow and pressure for each zone. Analysis is given for an example hypothetical building under different temperature, wind and air leakage conditions. Shows that the method can be used to evaluate the difficulty in opening doors due to pressure differentials and the noise resulting from air flowing through cracks around doors.

Describes a method for determining the rate of air change in a ventilated space using carbon monoxide as a tracer gas. Concentration of carbon monoxide was found by an infra-red analyser which proved to be very precise and sensitive and made it possible to carry out analyses in a short time. Air change rates were measured in a laboratory with open windows and with closed windows. Concludes that air change rates are greater with few large openings than with many small ones.

Reports measurements made on windows in old blocks of flats in Sweden. Measurements were taken of air-leakage through 21 windows under different air pressures before and after the renewal of draught excluders between window frame and casement. Concludes that draught proofing of old windows is extremely effective. Heat flow through 18 double-glazed windows is also measured and two systems of converting double to triple glazing are studied. Conversion was found to improve u values by approximately 35%.

Discusses the factors affecting air change rates in multi-storey buildings and derives expressions for the air infiltration through walls, windows and doors; air flow through gravity ventilation ducts; pressure pattern on the outside walls of the building and the "chimney draught" in the staircase. Derives mathematical model for calculating the air balance for a building with gravity ventilation ducts. Concludes that chimney draught (stack effect) has a large effect and that proper design of the extraction gravity ventilation system is very important.

Reports wind-tunnel tests on simple cubical model made of plastic to see effect of outside wall leakage on internal and external pressures. Three wind directions are studied and results extended to smoke-control problems. A method has been developed to modify the roof-vent design calculations to takewind effects into account. Shows failure of vent systems may bemore common than would be expected from current design methods.Concludes that leakage characteristics do not have any appreciable effect on outside wind pressures but do affect strongly the internal pressures.

Reports of tests on wood windows and doors to determine their thermal performance with and without wind. Additional tests to determine air infiltration effects were made and concludes that air infiltration has very small effect at low pressure differentials. Notes discrepancies between test results and ASHRAE design values especially when a 15m.p.h. wind was present. Recommends development of uniform testing and evaluation methods.

Discusses measurement of energy consumption and the large number of factors to be studied. Presents detailed measurements for two blocks of flats in Sweden taken partly during 1971/72 and partly during the oil crisis of 1973/74. In one of the two projects major savings were achieved by adjusting the heating system, reducing the room temperature and reducing the mechanical ventilation. About half of the savings made in the energy used for heating and ventilation (40%) resulted from reduced airing of rooms.

Reports measurements made in a flat in the Netherlands of internal to external temperature and pressure differences, wind speed and direction, position of windows and doors -whether opened or closed- and ventilation rates. Concludes ventilation rate can be predicted fairly accurately from wind velocity but energy consumption is not a linear function of wind velocity.