modelling

Defines term `ventilation efficiency' and notes factors which determine it: air change rate and temperature, sources of heat and pollution and their locations in a room, persons, machinery etc in motion, the design and position of inlet and exhaust air devices. Gives mathematical and illustrative flow models.

Describes wind tunnel study where both static and dynamic, local and spatially distributed loads have been measured for a variety of representative low-rise building geometries. Determines experimental pressure coefficients for the interior of buildings with various porosities and wall openings. Describes the assumptions made to reduce the large quantities of data to a small set of simplified pressure coefficient charts appropriate for use in a code or standard.

Reports on a comprehensive wind tunnel study of low-rise buildings at the University of Western Ontario, aimed at the definition of simple code specifications for the wind loading of such buildings. Describes an innovative technique for determining spatially-averaged time varying wind loads over various tributary areas of a structure. This data has been processed by computer to produce a time-history of more generalized loadings. Measurements have been carried out in turbulent flow conditions characteristic of thenatural wind.

Reports on an investigation concerning ventilation and energy conservation in dwellings, which was financed by the EEC and the Dutch Ministry for Housing and Public Works. Concludes that:< 1. In single family houses air flow through cracks and joints causes more ventilation then is required.< 2. Flats with more airtight construction provide better control of ventilation.< 3. The amount of wind protection plays a part as important as airtightness.< 4.

Presents and discusses mean pressure coefficients averaged over the entire side of a building, obtained from measurements made on models of rectangular flat-roofed buildings made in a boundary layer wind tunnel. Describes measurement technique and data collection. Pressure coefficients based on either a local reference wind speed or a reference wind speed measured at the level of the building have been computed. Gives example and a comparison with existing building codes and standards.

By observing animal housing in severely cold conditions it was realised that an airtight building with mechanical ventilation did not provide the optimum solution, but better results were obtained from porous buildings. Reports aninvestigation made on a large model building simulating the humidity and temperature conditions in animal housing during winter. The model had a porous ceiling of flax straw.

An earlier paper gave the flow to be expected through an open door from theoretical considerations. Describes model tests designed to check these theoretical predictions. The model used was 6.3% of full size and water was used instead of air for the flow medium. Concludes there is reasonably good agreement between model and theory.

Reports wind tunnel measurements of the wind-induced internal pressures of models of low-rise buildings of different geometry and internal volume. Three different uniform porosities (0.0 0.5 and 3.0% of the total surface area) have been examined in combination with openings in a wall ranging from 0 to 100% of that wall's area. Two terrain roughnesses were used corresponding to open country and suburban regions.< Finds that internal pressures are variable but generally lower than local external pressures.

The Alberta Home Heating Research Facility consists of six uninhabited wood frame single storey modules with full basements. Describes the modules which are designed to test domestic heating strategies in a northern climate. Reports a series of preliminary measurements of infiltration rate using SF6 as a tracer gas and measuring the rate of decay of the gas. Future studies are planned using SF6 in constant concentration.

Reports experimental measurements carried out in a boundary layer wind tunnel at the University of Western Ontario. Both external and internal pressures on two different models were measured with different porosities for the walls. Discusses results and concludes that mean internal pressures measured in thewind tunnel agree well with analytically predicted values that accurate evaluation of internal pressures is necessary to calculate building air infiltration.