English

Reduction in air leakage rates due to weatherization of homes can be determined by fan pressurization and tracer gas techniques, but only the latter gives the results under normal occupancy conditions. Assessment of such rates measured before and after weatherization must consider their dependence on wind speeds and inside-outside temperature differences.

A two-part experimental study was conducted to identify antecedents of complaints from office workers in a sealed, air conditioned building. Building illness was documented as increased incidence of absenteeism and complaints among office workers in the study group compared to control subjects in a non-sealed building of a similar age. The second part monitored complaints and symptoms from subgroups when lighting was changed and when fresh air was introduced. Complaints and symptoms decreased with changes in air and lighting and increased again when previous conditions were established.

The manufacturing procedures and performance of a building air infiltration kit consisting of miniature passive perfluorocarbon tracer permeation sources and passive adsorption tube samplers are described. 

The Brookhaven air infiltration measurement system (BNL/AIMS) uses a family of four passive perfluorocarbon tracer sources and miniature passive adsorbent samplers to inexpensively but very effectively tag individual zones within multizone buildings with uniquely discernible tracer vapors.

This is the third item in a series on methods for predicting condensation risks within structures. It answers criticisms made of the method described in NO 1729, on the basis that the method does not give the same answers, nor does it take account of the effect of the occurrence of condensation on the vapour pressure gradient within the structure, as does the graphical method described in NO 1728.

Describes in detail a computer-based technique for predicting the risk of condensation occurring in building structures. The technique not only indicates the position at which condensation is likely to occur, but also puts a figure on the risk of decay in timber within the structure. In the case of ventilated roofs or walls it gives the minimum sizes for ventilation openings.

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.