English

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.

Summary of an APCA International Speciality Conference. Contains information on some relatively unfamiliar trace gases and fungi, as well as on the better known indoor air pollutants. Studies range from those on human health tothose concentrating on pollutant emissions to those addressing building ventilation. Papers also cover sick building syndrome and pollutant and ventilation surveys.

The design of a low cost ventilation air heat exchanger which utilizes plastic sheets as the heat transfer surface is presented. Laboratory tests on such acounter flow heat exchanger have demonstrated very high values of overall heat transfer coefficients, heat exchanger effectiveness, and temperature recovery when the flow is laminar and buoyancy effects assist the heat transfer. The costs of such heat exchangers would make them attractive for many building applications.

A study was made of one hundred subjects who were exposed to air flow with a turbulence as occuring in typically ventilated spaces. Turbulent air flow is seen as more uncomfortable than laminar flow. Each subject participated in three experiments at air temperatures of 20, 23, and 26 degrees C, withvarying air velocity and turbulence intensity. Recommends a reduction of velocity limits specified in existing standards.

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.

Starting from the premise that condensation in the building envelope is a prime cause of its deterioration, the mechanisms that cause condensation are discussed and control measures explained. The conflicts that arise between some of these measures, the probability of achieving them under realistic construction conditions, and the possible need for fail-safe provisions should complete success not be achieved, are described.

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.

A design process is developed for an OCCUPANCY RELATED VENTILATION CONTROL SYSTEM (ORVCS) in a new entertainment centre in Sha-tin, Hong Kong. The aim is to reduce the cost of space cooling. Little work appears to have been done in using ORVCS in conjunction with space cooling up to the present time. Thedesign process includes (a) the selection of a control parameter to modulate the fresh air supply rate (b) assumptions about the occupancy load profile and (c) estimation of the possible energy savings.

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.