The feasability of using models for predetermining natural ventilation.

Discusses conditions that must be satisfied for a model in a wind-tunnel to give the same air-flow as a full-sized building. Reports two series of tests on interior and exterior air flow patterns, made on a full-sized building and a scale model of the building. Air flow patterns were observed using titanium tetrachloride smoke. Tests were also made to determine the limits by which the product of the height of the model by the air speed may vary without serious error.

Natural ventilation of large hospital buildings.

Wind-tunnel tests of hospital scale models and a computer program to calculate internal air flows were used to produce aprediction technique to determine the rates of natural ventilation of large hospitals. Technique was applied to aharness hospital design and article reports that the ventilation generated by wind forces in for instance, ward areas would not be consistently adequate for the comfort and well-being of the occupants.

Wintertime infiltration rates in mobile homes.

Reports measurements of air infiltration made on two mobile homes, identical except that one was treated with sheathing board and the other caulked. Carbon monoxide was used as a tracer gas and wind speed and direction, solar radiation, andoutside and inside dry and wet bulb temperatures were recorded. Finds considerable scatter in the data and analyses the reasons for this. These include the considerable sensitivity of infiltration rate to wind and instrument drift.

Radon in swedish buildings.

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.

Avoidance of condensation in roofs.

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.

Low pressure leakage function of a building.

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.

Air leakage measurement of buildings by an infrasonic method

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.

Shelter behind two-dimensional solid and porous fences

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.

Wind shelters.

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.

Theoretical model for relating indoor pollutant concentrations to those outside.

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.

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