English

Dynamic insulation has been used in non domestic buildings for 20- 30 years in order to reduce the heat loss and to bring preheated air into the buildings. Dynamic insulation means a construction where the air is being forced through the insulation, usually from the colder outside air into the heated building. The Norwegian Building Research Institute has been engaged to evaluate 12 row houses, with dynamic insulation used in the roof, which has been built in the Oslo area. 4 of the houses were monitored over a period of time.

The Building Research Establishment is currently investigating the impact of various radon remedies at a radon affected test house. Tests aim to assess how different ventilation strategies affect indoor radon levels and the building environment. Those examined include natural underfloor ventilation, mechanical underfloor ventilation (supply and extract), and whole house pressurisation. The test house has a suspended timber floor with an inaccessible underfloor space and is typical of much of the UK housing stock except for indoor radon levels regularly in excess of 1000Bqm^-3.

In order that sampling points may be strategically located, it is desirable to have knowledge of the spatial variation of ventilation eflectiveness parameters prior to measuring them using tracer gas sampling techniques. The research described in this paper is being carried out to establish a tracer gas sampling strategy as well as to facilitate the prediction of ventilation effectiveness parameters. The procedure developed requires the division of the internal space into a large number of cells and, by the application of CFD, the mass flow rates between adjacent cells to be established.

In this paper, we investigate the potential of an aerosol-based technique to significantly reduce the leakiness of residential air distribution systems (ADS). The first part is dedicated to a short review of theoretical analyses of particle transport and deposition in an ADS as well as particle removal in the leaks. The purpose of this review is to pre-determine the ranges of the flow rates, pressure differentials and miscellaneous characteristics of the particles that would allow plugging of the leaks in a relatively short time.

A computer program has been developed to predict the wind pressure coefficients Cp on facades and roofs of block shaped buildings. The program is based on fits of measured data, including wind shielding by obstacles and terrain roughness. Main advantages of the program are: - it needs no expertise of its users on wind pressures; - the input is simple. It exists of building and obstacles coordinates and orientations; - generating Cp values for ventilation model calculations needs no separate action.

There is an increasing concern at the possible health effects of fine suspended particulate (aerosol) upon human health, particularly in the urban environment. Aerosol infiltrating indoors may arise from transport, power generation and natural sources. Aerosol also arises from indoor sources, through cooking processes for example, and from animal dander. In zones within a building, within which the air is reasonably well-mixed, the levels of aerosol will depend upon the ventilation rate and the rate of deposition on indoor surfaces.

A study was set up to compare the effectiveness of passive stack ventilators (PSV) with mechanical extract fans (MEF) in providing adequate ventilation in UK homes. New build and refurbished homes with PSV and MEF were identified and questionnaires posted to 3000 households of which 1223 were returned. The survey showed that in homes installed with a PSV system, only 7% of those in the kitchen and only 8% of those in the bathroom were reported as blocked up. There were also few cases in which the MEF was blocked up or disconnected: 1.5% in kitchens and about 5% in bathrooms.

This paper describes the new indoor environment research facility recently constructed at the Institute for Research in Construction, National Research Council Canada. This facility allows full-scale testing and physical modelling of office space lighting, thermal comfort, indoor air quality, airflow and contaminant-flow patterns, ventilation, acoustical characteristics, and occupants' reactions to these parameters. The facility consists of a test room, approximately, 12 m by 7 m by 2.74 m high, with adjustable interior partitions.

So as to better understand and predict IAQ problems, the velocity field and distribution of local mean age of air were determined experimentally with three-dimensional anemometry and decaymode tracer gas measurements inside a classroom. We also performed 3-D numerical simulations of the velocity field in this room, using a CFD code. The time dependent concentration decay of tracer gas was simulated using the previously determined flow field in the pollutant transport equation. Relatively good agreement was found between the simulated and experimental concentration decay curves.

Disadvantages and advantages with different heating and ventilation systems in modern housing have been discussed during many years in Sweden. The discussion has intensified for modem low energy houses, where the use of forced air heating has increased during the last fifteen years, mostly in one-family houses. In many articles and the general debate diverging opinions have been presented concerning the thermal comfort, the air quality, the ventilation and the energy use in modern one-family houses with forced air heating.