residential building

Notes field evidence of increased condensation in houses with reduced ventilation and increased thermal insulation installed to conserve energy. Treats the possible long term effects. Gives advice on taking into account the whole package of heating and ventilation of the property when energy conservation measures are being contemplated.

Uses a model to estimate the incremental risk of lung cancer associated with increased radon concentrations in indoor air resulting from decreased air infiltration caused by increased air tightness of dwellings. Gives results for selected changes in the air exchange rate. Discusses findings.

Recent work by the National Radiological Protection Board indicates that higher than average levels of exposure due to radon occur in the South West. West Devon District Council has undertaken its own survey on radon concentrations to see whether these can be associated with lung cancer incidence. The control of radon gas is likely to have implications for building structure and ventilation. There is a potential conflict between the desirability of increasing ventilation to cut radon levels on the one hand and reducing air infiltration to save energy on the other.

A project was formulated for the purpose of studying the possibility of improving indoor climate in hot countries without the use of fans and/or air conditioners. This climate regulation technique is here termed passive climate regulation. In the present report the results of the first stage in a series of studies are presented and discussed. In this stage the principles involved are outlined and the computational techniques are demonstrated for relatively simple cases.

Centrally controlled mechanical exhaust air ventilation systems in residential buildings can satisfactorily serve only a few of the inhabitants. As the need for ventilation in each apartment varies both temporally and locally, the exhaust air ventilation system should operate accordingly. On the basis of a new cascade-control method a selfcontained constant flow exhaust air terminal device was constructed. With the device the user can, according to his own needs, increase temporarily his own exhaust air ventilation.

Each occupant in a room should be able to control his own indoor environment. Individual control can be achieved in many ways: from simple window-opening to automatically arranged personal mini-environment. Individual control is not utilized effectively today. This is partly caused by lack of proper information, and partly by the fact that builders pay more attention to construction than to use and operation. Even technically complicated systems can be easy to operate - what is needed is sufficient, but not too difficult user information.

In France, most of the ventilation systems in dwellings now consist of exhaust vents linked up with a fan, and air inlets. A survey conducted by the CSTB shows that actual ventilation rates are frequently different from prescribed values and that a lot of problems encountered are related to occupant behaviour, - The duration of exhaust flowrate peak value was measured ; it was shown that this duration was dependent on the kind of command and its location in the room. - draughts through air inlets were a major concern. - a lots of air vents did not operate correctly because of fouling.

The occupants' behaviour is one of the parameters which has the greatest influence on the air change in the dwelling. This applies both to naturally and to mechanically ventilated dwellings. On the basis of continuous measurement of the air change in 25 dwellings, the relation between the ventilation system and air change and between the number of occupants and air change is discussed. The air change in the 25 dwellings has been measured for a period of about one week during occupancy. The measuring principle applied is "the method with constant concentration of tracer gas".

The effects on ventilation behaviour of inhabitants in residential buildings have been investigated as a part within several years' German R and Dprogramme. The investigations have shown that the ventilation behaviour seems to be dominated by traditional behaviour patterns, e.g. ventilating bedrooms, and subjective impressions. There is only a modest correlation between window opening and needs for indoor air quality and energy conservation. Up to nowmost of the inhabitants do not assess correctly their own window opening behaviour.

Subjects covered include: problems of radon, formaldehyde build-up in the home, residential indoor air quality, effect of moisture on other pollutants, epidemiology of indoor air problems, setting standards for recognising harmful concentrations in homes, the effect of retrofit conversion measures, thepublic's perspective.