AIVC - Air Infiltration and Ventilation Centre

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air change rate

Natural ventilation of single family houses. Ventilation naturelle des maisons individuelles

Reports the results of three programmes of measurements of ventilation carried out in one-family houses, which in most cases were of the 'council house' type. The first programme measured ventilation rates using tracer gasin two houses room by room. Wind speed and direction were recorded but no general relation between ventilation and wind was found. The second measured ventilation rate in individual rooms in a house under six different wind conditions. The third measured ventilation rates in three identical homes.

Ventilation in small house Ventilation i smahus : kunskapsbrist minskar energispdrandet

Discusses actual ventilation rates in small houses and the requirements of Swedish building regulations. States that regulations do not take a total view of the energy balance in small houses, and pay no regard to the interplay between different forces.< Discusses a newly built 1.5 storey house as an example. Outlines problems in ensuring a low air change rate.

Wind effect on the air movement inside buildings.

Discusses the effect of wind on air change rates in buildings. Reports series of model tests conducted in a water flume and a wind tunnel. A plexiglass box with holes in it was filled with gas, either nitrogen or carbon dioxide, and placed in a controlled air flow. The concentration of gas was plotted in a semi-logarithmic form. Gives typical examples of these graphs.Discusses feasibilty of estimating rate of air change by a hyperbolic function, but finds that more tests are needed forpractical recommendations.

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.

Natural ventilation of modern tightly constructed houses.

Presents results of a survey of natural infiltration rates in 2 identical modern homes-one gas fuelled and one electric-over aperiod of a year. Infiltration rates were determined by releasing tracer gas, usually ethane, into the main return duct and measuring concentration every half hour. Discusses results and dependence of infiltration rates on wind speed and direction. Gives preliminary result that wind probably exerts agreater effect on infiltration than any other variable.

Measurement and calculation of the ventilation through a vertical sash-window without wind. Messungen und Berechnungen uber Stossluftung durch vertikal Schiebefenster bei Windstille.

Reports measurements of the natural ventilation through a vertical sash-window in calm weather. Describes test window and room. Gives theoretical expression for the ventilation depending on the amount the window is open, inside to outside temperature difference and the difference in height of the openings. Reports two tests of ventilation rate made using smoke. Concludes that a vertical sash window gives very good ventilation even without wind. Finds that tests corraborated the formula which would also apply to a deeper room.

Determination of combined air infiltration and ventilation rates in a nine-story office building.

Reports measurements of ventilation rates made in a nine-story office building. Two methods were used; tracer gas decay rate using sulphur hexafluoride and a direct method when air flow rates through roof vents and exhaust units were measured. Gives summary of results and finds good agreement between the two methods.

Measurement of ventilation with radioactive isotopes. Luftungsmessungen mit radioaktiven Isotopen.

Describes a method for the investigation of ventilation rate in mechanically ventilated closed rooms. The room air is labelled with a radioactive isotope and the ventilation rate inferred from the reduction in radioactivity found by repeated sampling at different locations . Notes the results apply only when the room air is well mixed. Defines a parameter, the "ventilation factor" which describes the variation in ventilation rate. Gives examples of the use of this method.

Air infiltration in buildings due to wind pressures including some neighbouring body effects.

Developes procedure for calculating air infiltration rates due to wind pressures on the exterior walls of buildings, assuming no chimney and mechanical ventilation effects. Assumes resistance to internal air flow is small. Using results of wind tunnel test, presents calculations showing the significant effects a single neighbouring building can have on the infiltration rates. Relative building heights, distance between buildings and wind direction are varied, and both uniform and shear flows are considered.

Measurement of air-change-rate in rooms without air-conditioning. Messung des naturlichen Luftwechsels in nichtklimatisieren Wohnraumen.

Describes the importance and purpose of measurements of air infiltration. Discusses methods of measuring air-change-rate and the range of measurements. Describes test method and gives preliminary results of practical tests made in living rooms during the winter of 1975/76. Results indicate that more detailed and comprehensive tests are necessary to obtain valid data for heat loss due to air infiltration in rooms and buildings and dependence of air-change-rates on year of construction and type of building.

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