English

Discusses the nature of stack effect, the distribution of air pressures across a building enclosure and its interior separations that stack action causes, and some of the implications of the resulting air flow patterns. Concludes that way in which stack effect is distributed across the building enclosure can be altered by design.

Reports 312 measurements of ventilation rate in 31 rooms in old and new blocks of flats, 3 villa residences and a modern university building, made using coal gas as a tracer. Describes buildings and gives main results. Examines effect on air change rate of sealing flues and gratings, opening windows and weather conditions. Finds outside wind speed has most influence on ventilation rate. Discusses recommended standards of air supply.

Briefly reviews air leakage around windows. Discusses heat loss through windows, dependence of leakage on pressure difference across windows, effect of leakage on condensation. States that tight windows can save heating and cooling costs but weatherstripping is necessary for tightness.

Presents results of measurements of ventilation rate and window air leakage made in blocks of flats in Sweden. Describes measurement of ventilation rate using nitrous oxide as a tracer gas and pressurization tests on windows. Gives graphical results of tests. Finds that the majority of windows do not satisfy 1975swedish building code. Reports measurements of air leakage of windows before and after renewal of draught excluders. Concludes that old windows can be made relatively draught-free and that this is not expensive or time consuming.

This paper is a general survey of work done on natural ventilation of dwellings. Discusses ventilation of houses with both natural and mechanical ventilation. Reviews experimental investigations, quoting air-change-rates found. Discusses ventilation requirements and methods for investigating different factors. Outlines suggested experimental method for investigating air infiltration of mechanically ventilated houses.

Reviews hazards from excess carbon dioxide and carbon monoxide in poorly ventilated spaces. Discusses ventilation rates needed to keep concentrations below safe levels. Reviews toxicity studies of portable fuel-fired appliances and gives simple guidelines for the use of such equipment.

Reports recent studies showing that seasonal efficiency of oil-fired residential heating systems is in the range 55-75% compared with steady-state efficiency of 80% or more. Finds this is due to effect of off-period draughts and of excess combustion air and draught control air on the infiltration loss for the structure. Discusses ways of improving efficiency. Finds sealed combustion systems may offer operating cost savings.

Describes series of wind tunnel investigations leading to development of a procedure for estimating wind pressure forces on low-rise building which is part of a large group of similar buildings. Procedure takes account of geometrical form of building, spacing of buildings, direction of wind and upstream fetch conditions. Gives estimated value as pressure coefficient which may be determined graphically.

Describes method of measuring air flow in mines using nitrous oxide as a tracer gas. Examines two methods of measuring airflow, releasing a continuous stream of a gas and releasing a known quantity of gas. Describes laboratory study andunderground tests of method. Concludes that technique is reliable and accurate.