The message of Annex 20: air flow patterns within buildings.

The International Energy Agency (IEA) task-sharing project "Air Flow Patterns within Buildings" was initiated in May 1988 for a duration of 3,5 years. Twelve nations contribute work and expertise and "share the task" specified in the project's objectives. This project and the AIVC belong to the same Implementing Agreement: The Energy Conservation in Buildings and Community Systems Program. As "Attachments" to the Implementing Agreement, they are called Annexes. The general objective of the Annex is to evaluate the performance of single- and multi-zone air and contaminant flow simulation techniques and to establish their viability as design tools. To reach this goal, the work was divided into two parallel subtasks: One on singleroom air and contaminant flow, the other on multi-zone air and contaminant flow and measurement techniques. This survey paper reviews project objectives and approach, both technically and from the point of view of project management. It offers an overview of the work performed and solutions contributed by the participating countries, it discusses problems encountered during the project and how these were solved, and summarizes final results. It shows how the various technical Annex-20 contributions to this conference are related to the overall Annex effort. General conclusions are drawn, consequences for future international projects are examined, and the main message of the multi-national program is formulated.