English

Radon is a radioactive gas which diffuses naturally from all mineral based building materials. States for most homes, concentration of radon is approximately inversely proportional to the ventilation, although this is not valid for very low or very high air change rates. Gives brief results of measurements of concentration of radon in dwellings. Outlines health risks from radon and daughters. Reviews norms laid down in some countries for specific situations. Discusses ways of reducing radon concentrations.

Describes a photo-electric technique for instant determination of contaminant concentration in wind tunnel studies of stack gas dispersion. A roving sensor is used to measure the light scattered by the particles of oily aerosol representing theprototype stack effluent. The minature probe has a noise level of only one hundred thousandth of the full linear range of the output signal for a time constant of 5s. Device is also suitablefor measurement of fluctuating flow properties, such as turbulence, where a high frequency response is required.

Reports investigation of the relative effectiveness of wall gratings and flues as means of naturally ventilating unheated closed rooms. Ventilation rates of several rooms were measured using carbon dioxide as tracer gas and wind speed and direction were recorded. Presents results and finds for the flue, ventilation increased with wind speed irrespective of direction. For grating, ventilation rate increases slowly with size of grating and is dependent on both wind speed and direction. Concludes flue with base opening of 15 sq.ins. is as efficacious as grating having 50 sq.ins.

Reports measurement of wind pressures on Royex House, a multi-storey building in London. Reports that suction loads on cladding are more severe than had been indicated by wind tunnel tests. Face-on winds produce the maximum structural loading with whole of peak load on windward face.

Reports tests using a natural exposure rig on a number of designs of horizontal and vertical joints employing labyrinths to separate the air and water entering the joint. Results obtained under a limited range of conditions show that it is possible, with suitable designs, to prevent penetration of water without necessarily making a joint airtight. Puts forward a number of potential applications, including a prototype window.

In 1978 the Swedish parliament adopted a ten-year "energy saving plan for existing buildings". Outlines energy saving measures which qualify for public support. Describes survey made of randomly chosen buildings, which had received loans or subsides, to evaluate their effectiveness. Describes collection of information and gives method for calculating energy savings. Reports preliminary result that extra attic insulation leads to substantial energy saving as did replacement of boiler and burner in multi-family homes.

Reports wind measurements made on a multi-storey building. Gives contours of overall pressure coefficients and wind velocity profiles. Compares results with series of wind-tunnel model tests and finds full-scale measurements were quite different from model tests. In an attempt to gain greater physical insight into the problem tests were made on a two-dimensional bluffplate immersed in a turbulent boundary layer. Finds correlation of drag coefficient with boundary layer parameters for quasi-equilibrium type layers.

Presents measurements of the mean and fluctuating pressure field acting on two-dimensional square cylinder in uniform and turbulent flows. Shows the addition of turbulence to the flow raises the base pressure and reduces thedrag of the body. Suggests this is attributable to the manner in which increased turbulence intensity thickens the shear layers, which causes them tobe deflected by the downstream corners of the body and results in the downstream movement of the vortex formation region.

Describes both the macro and micro meteorological structure of strong winds in the earths boundary layer. Discusses the wind speed spectrum, characteristics of mean flow and gustiness and the structure of turbulence. Concludes that almost all theproperties of the wind that might be needed in structural design can be estimated from the mean-wind field and the groundroughness. Suggests areas for further research.

Discusses pressure distribution on buildings. Describes wind tunnel tests on model buildings. Pressure distribution on walls were measured in a constant velocity field and in anartificially produced velocity gradient. Discusses results and deduces rules by which pressure distribution and wind loads can be predicted for buildings in any specified wind field. Changes in the flow pattern due to the velocity distribution were observed and correlated with the pressure distribution.