AIVC - Air Infiltration and Ventilation Centre

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air tightness

The effects of re-insulation on some houses in Winnipeg. A research report.

Energy-related variables were monitored in six detached houses in Winnipeg, Manitoba, before and after the houses were retrofitted by re-insulating the exterior walls and ceiling, or walls only, with blown loose-fill glass-fibre or cellulose

Humidity and ventilation in dwellings. Raumluftfeuchte und wohnungsluftung.

Energy conservation in dwellings has been realized mainly by tight windows and by improving heat insulation. Increasing damage to the building fabric by humidity and mould has been noticed. But there is no correlation between this damage and the improved insulation. Rather it is caused by too low ventilation rates. This paper deals with these problems in detail. Ventilation rates in the order of 0.5 to 0.8 per hour are assumed to be sufficient to avoid detrimental effects for the building and the inhabitants.

Building airtightness standards.

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 choice of airtightness and ventilation system for single family houses.

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.

Airtight houses. Timber frames for thermal comfort.

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.

Indoor air quality in tight houses: a literature review.

Reviews literature on indoor air quality in housing, nature of contaminants and their sources, health effects, standards and guidelines, impact of air sealing on indoor air quality, sources of uncontrolled air leakage, airtightness and natural ventilation, airtightness of new and existing housing stock, air change in new and existing housing, impact of air sealing on airtightness and ventilation, indoor air quality in tight houses, impact of occupant behaviour on ventilation, measures to improve indoor air quality, identifying problem houses, indoor pollution control strategies, and ventila

Air infiltration - modelling and practical results.

A steady state multi-cell calculation model has been developed in order to predict the interconnection between airtightness and ventilation rates. The model has been tested with measured leakage data of a detached house. 

Preliminary survey of air tightness levels in New Zealand houses.

Air tightness results for 40 New Zealand timber frame houses of varying age and construction detail are given. The steady pressure method was used at 6-9 indoor-outdoor pressure differences in the range 10-150 Pa. The data is presented in four ways: 1. air changes per hour at 50 Pa, 2. the coefficient and exponent of a generalized leakage function, 3. the leakage rate per unit shell area at 50 Pa, and 4. the equivalent leakage area at 50 Pa. Houses in the 0-5 and 6-20 year age groups were not significantly different in terms of air tightness.

Indoor air quality/air infiltration in selected low-energy houses.

Indoor air quality and air infiltration were measured in 16 low-energy Californian houses. Eleven houses had gas stoves: all had average infiltration rates of 0.5 h to the -1 or less, recent construction dates, low natural ventilation, and no mechanical ventilation.

Ventilation heat loss in a detached one family house.

For optimum building design it is of importance to investigate the comfort and the energy conservation obtained with different types of ventilation systems and levels of airtightness of buildings. This could be achieved by aid of computer models based on full-scale and model measurements. In order to obtain experimental data as input data to such a computer model, an experimental, detached one-family house has been built near to Gothenburg on the Swedish west coast.