English

Describes apparatus and test procedure used to measure air leakage through metal windows and gives test results. Concludes that infiltration loss through metal windows can be reduced by about 10% by locking an unweatherstripped window and by an average additional 56% by applying weatherstrips to the locked window.

States that to obtain accurate estimates of wind induced natural ventilation of buildings the pressure distribution over the building is required. Reviews the available information for isolated buildings and groups of buildings. Gives the results of wind tunnel measurements made on a cuboid when surrounded by buildings of the same shape. Results are presented statistically and indicate that the pressure distribution on a building can be fairly accurately determined provided the density of the built form and the roughness fetch are known.

Presents results obtained from a digital analogue method of calculating infiltration rates in building. The results are compared with a set of full-scale observations carried out by G.T.Tamura and A.G. Wilson. (abstract no.192). Finds that calculated and full-scale results give good agreement in terms of the rate of change of air infiltration rate with wind speed and that both show that total infiltration rate is more sensitive to wind speed than wind direction.

Surveys existing studies of natural ventilation which are of two types; full scale studies of small domestic buildings and analogue studies, mainly electronic digital analogues. Gives simple nomograms, deduced from the analogue studies which are useful for estimating gross building infiltration rates underextreme meteorological conditions. States that none of the analogue studies have been carried out in conJunction with simultaneous full scale or model scale studies in order to check their performance.

Describes a research project undertaken at the Building Research Station to measure wind pressures on the G.P.O. tower, London, and dynamic strains in the tower shaft. The development of a suitable pressure transducer which used strain gauges as sensors is described, together with the installation at the tower. some othe problems of strain gauging large civil engineering structures are outlined. NOTE Final results of this project are given in "Wind pressure and strain measurements at the Post Office Tower" Newberry C.W. Eaton K.J. Mayne J.R. abstract no.229. B.R.E. C.P. 30/73

Describes a computer program written in 1900 fortran which is suitable for computing natural ventilation rates in multi-storey buildings. Lists the assumptions made, the data requirements and output available. Gives a print-out of the program.

Describes research to study movement of air through fully or partially open doorways with and without influence of temperature, and to ascertain amount of supply air required toprevent this movement. Studies door openings of 0.10 to 104 m. wide and temperature differential of 0 to 12 deg.C. States that from these results critical areas in hospitals may be designed more effectively to given requirements.

Describes laboratory test performed on four steel swing windows and one steel double-hung window to determine leakage rates at different values of pressure and humidity. Concludes there is a wide variation in leakage rates of well constructed windows. Test results depend on the method of closing and latching windows, leakage for steel swing windows is found to differ when determined with ascending and descending pressure differences because the window is closed more tightly after completion of the ascending pressure difference.

Full scale measurements were made of wind pressures on the 177m high post office tower, London. The variation of pressure with height was studied from recordings made at nine different levels between 49m and 168m above ground level. It is suggested that wind speeds of greater magnitude than those at the top of the tower sometimes occurred at lower levels.

Reports results of studies conducted in Switzerland in small apartment buildings. Air change rates were measured in ten different apartment buildings using N2O as a tracer gas. Measurements were taken for various wind conditions andtemperature differences and with the windows partly open. Finds that ventilation rate increased by a factor of 4 when the windows on one facade were opened by only a few centimetres.