Sets out the mathematical techniques for determining 1 the most likely position of the condensation plane, 2 the limiting humidity at a given room temperature, below which condensation will not accumulate within the structure, 3 the rate at which condensate is likely to accumulate at the plane if the relative humidity within the structure persistently exceeds the limiting humidity. The technique is a graphical one and assumes that the conditions chosen for the purpose of the analysis remain constant indefinitely, a condition known as "steady state".
Reviews the existing standards of the AIC participating countries for whole buildings, windows, doors and building sections. Comments on the factors that should be taken into account in the application and future development of airtightness requirements, including climate, sources and severity of indoor pollution, ventilation requirements, existing practices, cost and overall impact of such controls on energy conservation.
The theoretical background, admittance measurements and experimental work on interstitial condensation in lightweight roofs caused by air leakages is discussed. Describes a theoretical model of condensation behaviour taking into account moisture transfer by air flow as well as diffusion. Gives the air flow admittance for various roofing materials, ceiling systems and different roof-sections. Experimental results agreed well with the theoretical model.
Facts and ideas are presented to improve cost effective designs for airtightness and ventilation systems. Schematically alternative measures to save energy are presented. An investigation of the rate of ventilation in 25occupied houses is described, using pressurization, tracer gas and measurements of air flow through exhaust air terminal devices. At a mechanical ventilation rate of 0.25 ach, the measured total ventilation rate averaged 0.29 ach (minimum 0.12 and maximum 0.50). Further results are given for 5 more recently constructed houses.
Uses air leakage measurements in laboratory and site studies in Poland to define a power law relationship between pressure acting across the opening and flow rate, and explains the effects on heat loss calculations. Results of indoor climate measurements over a two year period are given. Describes use of a computer model to calculate heat demand of different ventilation systems. Real heat requirement is about 40% larger than the calculated values.
Reviews the most important sources of indoor air pollutants, and means of measuring the contamination of room air by persons (carbon dioxide and odours). Lists some recommendations for minimum ventilation rates, based on the results of experimental investigations.
Indoor air quality research in Canada is outlined. 17 indicators are being considered in drawing up air quality criteria and guidelines for residential application. They comprise: carbon monoxide, carbon dioxide, radon and radon decay products, formaldehyde, aldehydes, nitrogen dioxide, microbiological agents, moisture, particulates, ozone, polycyclic aromatic hydrocarbons, chlorinated hydrocarbons, lead, pesticides, aerosols, synthetic fibres and asbestos, and oxides of sulphur.
Describes construction of timber-frame housing to high level of airtightness. A target level of 0.4 ach at 50 Pa was set. At this level, total air control provides an extremely high level of comfort by eliminating draughts and by supplying precise amounts of fresh air where required. An air and vapour barrier was installed within the house structure.
Describes a series of tests carried out in two interconnected environmental chambers, to determine the accuracy of airflows calculated from tracer gas measurements using a new rapid sampling system. The system is capable of measuring 3 tracer gases simultaneously.
During a 12 month period, an experimental house (retrofitted, with an air to air heat exchanger) and a control house are being monitored for various infiltration, indoor air quality and energy use parameters.
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