A sudden contamination of the outdoor air by some toxic gas can have several causes. The primary goal of the investigation was to determine the protection afforded by sheltering indoors. The object of a computational approach was a single family house with two floors. Three different models were utilized as computing tools: MOVECOMP to calculate the infiltration air flows, MULTIC to calculate the contaminant transport inside the building and TDYN to calculate the temperature decay of the building.

The amounts, quality and factors affecting of dust accumulation in supply air ducts of eight nonindustrial buildings were studied. The average of surface density of dust settled in supply air ducts was 10.6 g/m² and the average of yearly accumulation rate was 3.5 g/m²*year. The dust contained 82% of inorganic material, which agrees well with the composition of outdoor air dust in down town areas. In straight air duct the surface density of settled dust decreased as a function of distance from the air handling unit (AHU).

The dour threshold value of kitchen exhaust air was experimentally determined during typical cooking situations and tobacco smoking in a dwelling. During cooking, air from the exhaust duct was taken into a sample bag. The dour threshold concentrations of the samples were determined by sensory evaluation using olfactometer and untrained dour panel. Experiments were made both in laboratory and field settings. The largest dour threshold concentration of 168 o.u./m³ was determined during the frying of herring.

A humidity controlled exhaust fan have been tested during the winter season 1991/2. The test have been carried out in a detached one storey house with a flat roof. The relative humidity (RH) have been measured in the following modes: * natural ventilation only* wall mounted fan, setpoint 70% RH, and natural ventilation * fan in the exhaust duct, setpoint 70% RH.The relative humidity levels have been monitored in the shower room and in the other part of the dwelling. The temperatures have been measured in the exhaust duct and in four places in the dwelling.

Radon is the largest source of risk to human health caused by an indoor pollutant, at least in the industrial countries. Subslab Ventilation (SSV) is one of the most effective and common methods of reducing indoor Rn concentrations in houses with a basement. In this paper, we first quantify the impact of this technique on the air exchange rate, through numerical modeling of a prototype house with basement for a range of permeabilities of soil and subslab aggregate and various sizes of the cracks in the basement floor.

Due to the complexity in describing the simultaneous effects of a number of factors that influence the climate of an attic space it has proven to be difficult to make simulations of it. This report deals with the problem of using different computer programs for ventilation, heat andmoisture balance in an integrated way so that a proper description of the expected attic climate can be achieved. A general overview of attic space climate and the factors affecting it will be given and it will be described how the simulation packet works.

Besides the hygienic aspect, also the aspect of energy saving of heating residential buildings is very important. This is only possible by mechanical ventilation with heat recovery. This paper describes a part of the large variety of systems, which are nowadays available on themarket. The main difference of these systems are: * single room unit/decentral unit and * central unit for one dwelling or a single family building.

By means of parametric analyses, the paper describes how the "constantness" of a Constant Air Volume system is affected by temperature differences resulting from heat load variations or otherwise. Several design related parameters are considered. The paper starts with the background, then an outline of the (simulation based) approach, and how calculations were performed. Results are shown with respect to consequences for volume flow rates and for energy consumption.

The ventilation rate in a building depends on many things, one of which is the air temperature. The air temperature in turn depends in part on the ventilation rate. The effects of this relationship are generally overlooked in both thermal and ventilation models. To study this effect a model has been developed which integrates the models GAINE and SILONA developed at CSTB. This allows the prediction of the natural ventilation rates caused by the actual temperatures in the building.

This report presents the results from the registration throughout a month of relative humidity, temperature and outdoor air exchange as well as the concentration of carbon dioxide in each room of an inhabited single family house, in which all rooms are ventilated by a mechanical balanced ventilation system with variable air volume. The outdoor air rate is controlled by the relative humidity, which is kept on a value adequate to reduce the living conditions for house dust mites and prevent condensation on the indoor surfaces of the building.