Gives method for calculating air infiltration through window cracks. Calculates pressure drops across windows in buildings for four types of building and discusses resulting pressure differences. Gives values for crack width and length. Recommends design values for rates of air change due to infiltration in buildings heated by off-peak electricity.
Outlines the problem of assessing the rate of heat loss from dwellings due to ventilation. Discusses the mechanisms and pathways of ventilation and ways of controlling air infiltration. Reviews methods of measuring ventilation using tracer gases. Discusses qualities of ideal tracer gas and three automated measuring systems. Reviews some experimental results obtained from the SEGAS test house. Describes house and measurement method. Finds sealing house reduced ventilation rates by between 30 and 45 per cent.
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.
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 the research being undertaken by the British Gas Corporation on adventitious ventilation. Outlines a test house programme which has quantified adventitious areas for both room components and progressively sealed rooms in dwellings of varying age and construction. Describes a model scale approach to natural ventilation aimed at predicting room air movements and ventilation rates. This work is compared with full-scale results and theoretical models.
Examines dependence of measured infiltration rates on wind speed, indoor/ outdoor temperature difference and pressure difference. Gives results in form of graphs of measured values. Calculates air-change-rate from crack length and finds good agreement with measured air-change-rate. Suggests that this is as a result of over-estimating the effect of wind and neglecting stack effect. Finds that stack effect is more important than wind. Comparison of the two houses found that the house shielded by trees and houses had a considerably smaller infiltration rate than that on an open site.
Reports investigation of air infiltration in two residences using helium as a tracer gas. Describes the residences, instrumentation and test procedure. Gives results of decay rate of tracer gas and measured infiltration rates. Summarizes test conditions in tables of temperature, wind speed and direction, internal to external pressure differences and height of the neutral zone. Concludes that in houses with warm-air heating systems a single helium analyzing cell in the return air-stream would provide a satisfactory indication of house infiltration rate.
States that the calculation of transient pressures in buildings requires the estimation of the rate of air leakage through various paths. Gives an expression for infiltration through a wall component. Gives formulae for calculating pressure transients inside a building under forced ventilation with air leaking out of the building under various conditions. Theseformulae also apply when air is leaking into the building. Discusses practical applications and the practical problems for which the formulae are useful.
Describes continuous measurements of wind induced pressure differences across the exterior walls of two schools taken over a period of 8 months. These schools were selected from a total of eleven schools whose air leakage characteristics had been previously studied. Calculates air infiltration rates caused by wind using the measured differentials. Evaluates equivalent pressure differentials caused by wind. Calculates uniform pressure differentials caused by stack action using a computer model.
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