AIVC - Air Infiltration and Ventilation Centre

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air tightness

Accuracy in pressurization data analysis.

Several different ratings of building airtightness are used to report the results of fan pressurization tests. These are generally based on airflow rates at specific reference pressures, predicted by curve fits to the test data. The statistical

Relation between indoor air formaldehyde concentrations and ventilation rates for a group of sixteen new houses.

This study examines the experimental determination of the apparent net formaldehyde source strength in a group of sixteen nominally identical wood frame houses built by one contractor using similar construction details and materials. The houses

Ventilation of timber flat roofs.

A major cooperative study of the effect of ventilation of timber flat (cold) roofs on combatting condensation and moisture accumulation has been undertaken in Denmark. Field measurements of moisture content in a number of test roofs over long periods and under different conditions are evaluated and conclusions drawn. They include the advice that, where moisture accumulation is a problem, it can be aggravated if roof vents are installed.

Possible health effects of energy conservation: impairment of indoor air quality due to reduction of ventilation rate.

Efforts to reduce the energy needs to heat or cool dwellings have the potential to create new health hazards. Increases in indoor levels of radon and its progeny from the reduction in air exchange rates add a substantial radioactive burden to the general population. Other indoor pollutants reaching critical concentrations in homes with low air exchange rates are CO and NO2 from unvented combustion in gas stoves and heaters, tobacco smoke, and asbestos fibres.

Indoor radon levels: effects of energy-efficiency in homes.

The expectation of elevated 222Rn levels in modern homes that have low air interchange rates with the outdoor air led to a survey of both conventional and solar homes in northeastern New York State. As a group, homes that are more airtight ha

The aerodynamics of roofs: the influence of pressure and air flow on tightness. Aerodynamique des couvertures du point de vue de leur etancheite: pression, ecoulement d'air.

The aerodynamic forces affecting wind and rain penetration of roofs are described. They are: 1 the wind and its turbulent nature, 2 the induced pressure field, 3 the air flows in contact with the roof and 4 the characteristics of the roof (internal pressure, permeability, structure, etc).

Radon concentrations and infiltration rates measured in conventional and energy-efficient houses.

To elucidate any connection between high radon concentrations and low-infiltration houses, the 222Rn concentrations and infiltration rates have been measured concurrently in US houses. Three housing surveys have been undertaken: one in energy-efficient houses located throughout the US and twoin conventional houses in the San Francisco area and in Maryland. In each of the groups surveyed, no clear correlation was observed between 222Rn concentrations and infiltration rate, although each parameter varied over a wide range.

Towards the zero-energy house.

Concentrates on low energy housing construction in Scandinavia, and Sweden in particular, where typical new detached houses with a floor area of 140 m2 now use less energy for space heating than water heating. 

The infiltration component of ventilation in New Zealand houses.

The air infiltration component of house ventilation is calculated and discussed in relation to winter space heat losses and rneasures necessary to control moisture. The airtightness of 80 houses sampled from three major urban areas was inspected for association with location, external cladding materials, and design features such as the shape and complexity of the building envelope. A useful correlation of airtightness with envelope complexity emerged which gives a coarse but useful way of forecasting airtightness from building design information.

The effects of re-insulation on 8 houses in Ottawa. A research report.

Experimental measurements have been conducted on eight houses in the Ottawa area to study the changes induced in house performance when loose-fill insulation is installed in walls. The report presents details on the induced changes in furnace performance, house airtightness, temperatures, humidity levels and position of the neutral pressure plane. ECAP (Enhanced Conservation Assistance Program) auditing procedures were applied to the houses, and the predicted fuel consumptions showed a considerable disagreement with actual values.