Case studies in air infiltration

Describes the original series of case studies made by Dick and his associates between 1949 and 1951. Reviews current activities, divided by building types and discusses the problems and needs of future work. Recommends research and development projects and project areas.

The formation of two-stage joints

Describes different methods for sealing joints. Gives method for testing permeability of joints to wind and rain. Concludes that two-stage joint seems to offer the greatest advantages which are long life, lack of need for maintenance, lack of sensitivity to tolerances, extensive lack of sensitivity to faulty installation practice and installation independent of the weather. Tests confirm that the wind permeability of two-stage joints can be practically disregarded in the determination of heat requirements.

Use of a portable gas chromatograph and tracer gas for rapid determination of air ventilation rates

Describes method of measuring the air-change rates using sulphur hexafluoride as a tracer gas. The system comprises a highly portable gas chromatograph with an electron capture detector. The system will detect tracer gas without interference from other materials which may be present. The technique takes about six minutes to determine the ventilation rate. Gives practical examples and suggest extensions of the technique for carrying out cross air movements, for example in a hospital.

Fundamentals of moisture and energy flow in capillary-porous building materials

Discusses basic physical features of combined energy and moisture flow in porous building material. Discusses mathematical and physical structure of these dynamic processes in terms of local thermodynamic equilibrium, flows induced by gradients in intensive state variables and conservation of energy, moisture and other components. Gives conditions for thermodynamic equilibrium, discusses peculiarities of pore-water tension, and problems concerning energy flow. Deals with the causes of hysteresis and the complications due to hysteresis.

An intercomparison of tracer gases used for air infiltration measurements.

Reviews ideal characteristics of a tracer gas and gives literature review of the subject. Reports tests made on a house in California giving a direct intercomparison between common tracer gases used to measure air infiltration rates in buildings. Results indicate that air exchange rates measured using sulphur hexafluoride are slightly larger than thosemeasured using methane or nitrous oxide. The ratio of air change rates measured using sulphur hexafluoride to air change rates measured concurrently using a lighter tracer gas was found to be 1.10 +/- 0.10

Wind loads on a building model in a family of surface layers

Describes how a family of simulated neutral atmospheric surface layers was used to determine the response of the wind loads on a building model, as well as the associated flowfield near it, to variations in the characteristics of these 'test boundary layers'. Results include the variation in the size of the horse- shoe vortex at the base of the building, spectra of pressure fluctuations, and documented variations in the wake Strouhal frequency with changing boundary layer characteristics.

The optimum use of coniferous trees in reducing home energy consumption.

Refers to earlier work by Mattingly, Peters, Harrje and Heisler which indicated the possibility of reducing air infiltration by using sheltering devices such as fences, neighbouring buildings and trees. Reports use of wind tunnel air infiltration model to explore the effect of trees in a windbreak on a model home. Presents results of tests determining the effect on wind-induced air infiltration of the variation of various windbreak layout parameters. Introduces concept of turbulence generation as the mechanism of tree wind sheltering.

Air infiltration through revolving doors.

Describes experiments made to determine the air infiltration rate through revolving doors. Estimates infiltration by combining air leakage past the door seals with infiltration caused by the revolving of the door. Finds that air exchange depends on door speed and temperature differential and somewhat on wind and indoor air velocities. Gives flow past the door seals as function of indoor -outdoor pressure differential and flow related to door movement for a motor- driven revolving door and for a manually operated door for traffic rates up to 2000 people per hour.

The measurement of the rate of air change.

Gives an account of a method of measuring the ventilation rate of a room using hydrogen as a tracer gas. Describes katharometer used to detect the gas and the experimental procedure. Results agree well with those calculated by orifice plate method.

Measurement of ventilation using tracer gas technique.

Outlines ventilation measurements being made on two storey semi-detached houses using helium as a tracer gas. Describes measurement of decay rates in single rooms, the recirculation between two rooms and by summation the ventilation rate of thewhole house. Describes installation used to measure ventilation rates when homes are occupied without interfering with the normallife of tenants.