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.

A fundamental objective of this report is to investigate the techniques used in the design and research fields for the evaluation of thermal and air flow simulations. The scope is restricted to the whole building rather than flow and heat transfer within individual structural elements (e.g. cavity walls). Considerable developments are taking place in the field of air flow and thermal simulation. Rather than present an in-depth study of these developments, this report concentrates on the rather more general aspects of the combined simulation.