English

Describes technique for measuring the volume of air leaving a house through the loft. Two tracer gases are used; nitrous oxide is released in the house and carbon dioxide in the loft. The mean concentration of N2O in the loft gives the volume of house air infiltrating the loft: and the mean concentration of CO2 gives the ventilation rate of the loft itself.< Gives two examples of the use of this technique and gives loft ventilation rate as a function of wind speed for one house.

Outlines two techniques for estimating ventilation heat losses in houses. The first is a tracer gas technique using a constant concentration of gas and the second a theoretical prediction method. The theoretical technique treats the building as a multi-cell model with specified wind pressure, leakage openings and background leakage area. Reports use of the method for simulating the natural ventilation of a house in London and the effectiveness of sealing the windows and floor.

Reports experiments carried out in a wind tunnel on two kinds of two-dimensional roughness arrays and on one array of three-dimensional roughness with a turbulent boundary layer growing over the arrays. Drag coefficient on an individual element was measured by pressure tapping as its height was varied relative to the average height of the array. Some general forms for the drag coefficients are found for the two-dimensional case. Results for the three dimensional case show some general trends but more work is needed.

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.

A review of literature reporting investigations of pollution in enclosed spaces. Discusses pollution in sealed environments such as submarines, the relation of indoor to outdoor pollution, sources of indoor pollution, and tobacco-induced pollution. Outlines problem of pollution in transportation- related enclosures such as tunnels, subways and garages. Suggests that indoor pollution in public office buildings is of greater potential harm than outdoor pollution. Gives 18 tables summarising measurements of various indoor pollutants made by different studies.

Discusses the problems of sealing double glazing to reduce condensation between the panes. Describes sealed glazing unit and sealants used. Discusses causes of failures. Reports tests for seal leakage made by lowering air pressure surrounding theunit and observing glass deflection. Windows were also tested by weathering in the laboratory and by exposure to actual weather conditions. Discusses results and finds extreme difficulty in providing and maintaining an effective sealing system.

Presents mathematical model for predicting the heat transfer and moisture- transfer processes in residential attic spaces. Uses model to predict attic ventilation rates required for preventing condensation or frost accumulation on the underside of roof sheathing. Gives attic ventilation charts covering a wide range of outdoor temperatures, ceiling thermal resistances and ceiling air penetration rates. Finds that the addition of a ceiling vapour barrier reduced the required attic ventilation rate by36%, but the effectiveness of a vapour barrier was reduced by air leakage into the attic.

Describes computer program for the prediction of the air infiltration load in small residential buildings. The model represents an oil-fired furnace, a smoke pipe with barometric damper, a chimney and a non-partitioned building, with leakage openings in the building envelope. The model can be used to predict the air change rate of a small house under various combinations of indoor/outdoor temperature, wind-speed, wind direction and operation of an oil fired furnace.

Describes the mathematical methods employed in the ENCORE-Canada computer program which predicts the hourly as well as the annual heating requirements of small residential-type buildings. The model includes the effects of thermal storage, internal heat gains, basement and air infiltration losses, transmission heatlosses and solar heat gains. The heating system is a thermostatically controlled oil-fired furnace with warm air distribution. Hourly solar radiation and weather data forvarious Canadian cities are used to simulate outdoor conditions.

Describes the results of a major study to find out whether or not wall insulation installed without a vapour barrier causes an increased risk of moisture damage within walls. The exterior walls of 96 homes in Portland, Oregon were opened. Presents results of field and laboratory tests which show the absence of indications of moisture damage. Gives data on shrinkage and settling of insulation and results of air leakage measurements by fan pressurization tests. Concludes that the addition of wallinsulation without a vapour barrier does not cause moisture damage in existing homes.