English

Reports investigation of air infiltration in two residences using helium as a tracer gas. Describes the residences, instrumentation and test procedure. Gives results of decay rate of tracer gas and measured infiltration rates. Summarizes test conditions in tables of temperature, wind speed and direction, internal to external pressure differences and height of the neutral zone. Concludes that in houses with warm-air heating systems a single helium analyzing cell in the return air-stream would provide a satisfactory indication of house infiltration rate.

States that the calculation of transient pressures in buildings requires the estimation of the rate of air leakage through various paths. Gives an expression for infiltration through a wall component. Gives formulae for calculating pressure transients inside a building under forced ventilation with air leaking out of the building under various conditions. Theseformulae also apply when air is leaking into the building. Discusses practical applications and the practical problems for which the formulae are useful.

The overall air leakage of high-rise buildings cannot be measured using a full pressure method because of the large volume involved. Describes a method of conducting small-scale pressurization tests on the exterior walls of apartments in multi-storey buildings. Gives results of measurements in a test building. compares direct method with values obtained by summing the air leakage of individual components. Finds good agreement. Concludes that floor/wall joints, windows and window sills are the three major air leakage sources in exterior walls.

Describes a pressure transducer which was specially developed to measure wind pressures exerted in buildings. The instrument, which gives an electrical output, is suitable for measuring pressure in the range of 1200 n/m2. The frequency response enables pressure fluctuations lasting only 0.1 s to be recorded.

The two-storey house at Aylesbury, England, built by the Building Research Establishment for the full-scale measurement of wind pressures has been modelled at 1:500 scale in a boundary layer wind tunnel to verify the reliability of simulation forlow-rise buildings. Describes wind tunnel tests of buildings models of 5 and 22.5 roof slope. Compares surface pressure measurements with full-scale data for various wall and roof locations. For the model terrain best modelling conditions, the results show agreement which is encouraging.

Describes continuous measurements of wind induced pressure differences across the exterior walls of two schools taken over a period of 8 months. These schools were selected from a total of eleven schools whose air leakage characteristics had been previously studied. Calculates air infiltration rates caused by wind using the measured differentials. Evaluates equivalent pressure differentials caused by wind. Calculates uniform pressure differentials caused by stack action using a computer model.

Describes experiments aiming to estimate the protection afforded by a shelterbelt on the plains area of America. Describes three test houses and gives test results. The three houses were unprotected, partially protected and closely protected by a slat fence. Gives basic data in the form of fuel use, wind and temperature. Concludes that the reduction in wind speed by windbreaks is of the general order of 35% with a proportional saving in fuel. Finds that the area of tree shelterbelts has themost important effect on the degree of wind reduction.

Reports project to measure wind pressures on low-rise buildings. Describes site and houses in the estate selected for investigation. Gives details of an associated experimental building. Outlines positioning of the pressure transducers andgives details of the cabling and the reference pressure system. describes velocity measurement, recording equipment and methods of calibration, processing and analysis. Gives details of records taken in tabular form.

Describes computer program used to calculate air flows and pressure differential in a building as a result of a combination of wind effect, stack action and the operation of air handling systems. Describes mathematical model of building and the assumptions and limitations of program. Gives listing of complete program.

Gives short state-of-the-art review of knowledge of wind turbulence. Mentions results from field investigations. Summarizes available knowledge. An appendix discusses hot-wire anemometry. Gives bibliography of subject.