English

The paper describes the application of a new tracer gas technique for studying ventilation. The technique is called the homogeneous injection technique, since it relies on the continuous injection of tracer gas in all parts of a zone-divided ventilated system, with tracer injection rates, which are strictly proportional to the zone volumes. The steady state concentrations of tracer gas in the different zones are proportional to the local mean ages of air.

The aim of this study was to unravel the occupational exposure to radon among underground workers. The possibility for radon mitigation by improving ventilation or by sealing was also investigated. 65 workrooms in 19 workplaces has been investigated in the ground floor, in basements and in underground spaces in southern Finland and in middle Finland. Radon concentration varied from 15 to 1636 Bq/m³du ring working hours resulting in annual dose of 0.09 to 10.3 mSv.

BRE have experimental data for the flows found in Passive Stack Ventilation (PSV) ducts from a test house in Garston. These data cover different duct diameters, number of bends and roof terminals, all measured over a variety of weather conditions. In the first part of this paper the data are analyzed to separate temperature and wind effects, and to see how well they fit well to the expected model of duct flow. The second part gives a comparison of the same data with predictions from the single zone ventilation model BREVENT.

A possible alternative to mechanical extract ventilation for kitchens and bathrooms is passive stack ventilation (PSV). BRE has carried out work on this type of system in a test house under controlled conditions. To find out how well they worked in practice, four occupied dwellings were monitored over a period of 2 - 3 weeks each. Each dwelling had two ventilation ducts. Air flow rates within the ventilation ducts were measured, together with humidities, temperatures and climatological data.

The Annex 27 (A27), Evaluation and Demonstration of Domestic Ventilation Systems, is given a genaral introduction. The habits varys a lot between individuals, the dwellings are of various sizes with various numbers of occupants being at home for longer or shorter times. Those facts needed to be collected in the beginning of the annex. In this paper background data will be given to make it possible to discuss the varied need for outdoor air supply in dwellings. Data for the parameters have been collected from many sources.

Blower Doors are used to measure the air tightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems, quantification of airtightness data is critical in order to answer the following kinds of questions: What is the Construction Quality of the Building Envelope? Where are the Air Leakage Pathways? How Tight is the Building? How Much Ventilation Does the Air Leakage Supply?

The Building Research Establishment has set up various passive stack ventilation systems (PSV) in a test house in order to assess their performance. The test house used was a two storey, end terrace dwelling on the BRE site at Garston. A PSV was installed in the kitchen of the test dwelling. The duct material, diameter and configuration were varied to determine any differences that they would make to the air flow rates obtained in the duct. In addition, three different ridge terminals were tested and three ceiling inlets.

A design guide for displacement ventilation (thermally induced ventilation ) has been prepared. It is based on quasi stationary experiments carried out in the Sulzer Infra laboratory in Winterthur. The significant design parameters identified by factorial analysis are the air flow rate, the internal load, the convective part of the internal load and to a lesser extent the room height. Using a linearized polynom representation for the temperature increase near the floor as well as for the vertical temperature gradient in the occupied zone a design nomogram has been obtained.

Some radon mitigation systems draw air with a high radon concentration from under the basement floors of houses and exhaust it outdoors. The objective of this project was to measure the reentry rates of radon released at roof level and at ground level near a house to determine whether exhaust above the roof is necessary. This was done by using a portable mockup of a radon mitigation system exhaust, with sulfur hexafluoride (SF6) as a tracer gas.

Organisations in many countries have contributed data to the AIVC to establish a unique collection of numerical data suitable for design purposes and model evaluation. By combining information from these multiple sources, it is possible to consider a far wider range of operating conditions than would be possible by using the results from a single set of measurements alone. The analysis presented in the report is in three sections covering component leakage data, whole building leakage data and wind pressure evaluation.