This paper tries to give a reasonable description of the state of the art of the Belgian building stock with regard to ventilation. The Belgian research projects on ventilation in buildings, which were carried out recently, enable a precise overview of the quality of the Belgian building stock to be gained. It shows that airtightness varies a great deal from one building to another. Very leaky as well as very airtight buildings are frequently found. Notable is the near absence of controllable ventilation provisions.
The paper presents the development of a ventilation scheme for a large bus station and passenger interchange in Bilbao, Spain. The main objective of the design was to ensure that pollution free conditions could be achieved within an enclosed waiting area that opened up on to, and was surrounded by, a semi-enclosed pick-up space, where there could be large number of buses with their engines running. Initial thoughts were to use natural ventilation, architectural and other constraints made this impossible so mechanical ventilation became necessary.
In the framework of a project of the International Energy Agency (IEA) , IEA-Annex XVIII - Demand Controlled Ventilating (DCV) Systems, which started in fall 1987, a review of the state of the art of already existing DCV systems and devices has been undertaken by all participating countries. This paper is concerned with air quality sensors which may be suitable to control air quality on demand. The dominant contaminants are not only variing in different kinds of buildings (dwellings, schools, stores etc.) but also from room to room due to different ways of utilizing the spaces.
The ventilation performance of a proposed naturally-ventilated court-room was predicted and assessed on a statistical basis with regard to the local meteorological conditions. Summertime ventilation was to be provided via an underfloor duct and controllable vents at roof levels, under the action of wind and buoyancy forces. Wind pressure coefficients expected on the external facade of the building were obtained from wind tunnel measurements on a scale model.
The ventilation of a test room (LxWxH = 5.4x3.6x2.4 m) with a wall mounted heat source is investigated for two different air terminal devices. The properties of each air terminal device are described by measuring the velocity decay of the primary wall jet below the ceiling. The velocity distribution in the plume above the heat source has been measured at different heat loads as a function of the distance to the wall and the distance to the heat source.
This paper deals with field experience of airborne moisture transfer problems in houses. Two types of phenomena are discussed in more detail; the infiltration of moist air from crawl spaces and the propagation of moist air produced in kitchens. A modified depressurisation test is described to determine the air tightness of ground floors. A case study is briefly discussed where different remedial measures have been tested to evaluate the moisture removal effectiveness in kitchens.
Air exchange rates in occupied buildings are difficult to assess due to their dependence on a multitude of climatic parameters and inhabitant behaviour. Moreover, the assessment of the influence of the air exchange rate on the radon progeny concentration is hampered by the diurnal and seasonal fluctuations of the indoor radon levels.
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