Outlines problem of radon in buildings and current state of knowledge. Suggests reduction of radon by a) more efficient ventilation, b) use of diffusion resistant films to seal wall surfaces and c) elimination of certain active materials. A research project at the Swedish Council for Building Research is currently investigating the problem.
Sets out in general terms the design principles for avoiding condensation in roofs, pitched and flat. Recommends providing arain shield permeable to water vapour, a vapour barrier on thewarm side of the structure and in roofs with air spaces to ventilate the air space or blow dry air into the roof space.Discusses application of these to particular types of roofs.
Outlines the problems of modelling air infiltration. Reports measurements of the leakage function measured at low pressures using an alternating pressure source with variable frequency and displacement. Synchronous detection of the indoor pressure signal created by the source eliminates the noise due to fluctuations caused by the wind. Presents comparisons between these results and extrapolations of direct fan leakage measurements.
Describes an infrasonic method as an alternative to blower method for measuring the composite effective size of all the air-leakage passages of a building. Sinusoidally varying volumetric flows between 0.05 and 5Hz are generated by a motor-driven bellows-like source located inside the building under test. Resulting pressure variations are measured using a microphone-like sensor having an electronic signal processor. Reports system design and test results obtained to date. One house, five apartment and three interior rooms have been tested.
Reports measurements of the wake flows behind solid and porous fences, made with a pulsed wire anemometer (PWA) and a hot-wire anemometer (HWA). Discusses results which show the superiority of PWA in correctly measuring the highly turbulent and sometimes re-circulating wake flows. Gives empirical formula for profile of the velocity defect and shear stress perturbations. Concludes that porosity, and not the form of construction of thefence, determines the structure of the wake flow. States that in general it is difficult to say which value of porosity provides the best shelter.
Reports study of the aerodynamics of wind breaks in a boundary layer wind tunnel. Describes flow patterns and shelter effects in the lee of different fences and discusses efficiency of shelters in relation to pedestrian comfort. Gives results downstream in horizontal planes by nets of isocurves showing mean speed and turbulence. Discusses the influence of permeability, shape, size and wake ventilation and suggests new designs: for example two wind breaks in series.
Discusses in detail a general ventilation model, which relates indoor pollutant concentrations to those outside. When the time interval associated with changes in the outdoor concentration islong compared to that required either to change the air within the building or to remove the pollutant by internal means, the indoor concentration of pollutant can be related to the outdoor concentration by means of a simple expression. Finds good agreement between theory and experiment. Suggests method for reducing indoor ozone levels in California.
Reports study of indoor climate-primarily air quality-and energy consumption in a number of detached houses in a group housing area. All the houses were pressure-tested over three years; 1977-1980 and a relatively larger increase in air leakage was measured after the houses had been occupied for approximately one year. Suggests this is due to the drying out of timber, producing cracks. Two types of houses, a and b were investigated when studying indoor climate. both were mechanically ventilated.
Gives preliminary report of a study of natural ventilation and energy consumption in low-cost housing. The study includes the measurement of infiltration rates using tracer gas, pressure differences across outside walls, indoor and outdoor temperatures, air tightness of external walls and the position of windows and doors. Outlines future studies and gives preliminary conclusion that making houses more air tight can save energy.
Considers the rate of natural ventilation required in a room to maintain a healthy concentration of oxygen given the efficient sealing of windows against draughts. Includes a nomogram toassist the calculation of a rate of air introduction according to the height of the building, wind loads, and type of window construction.
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