It is often assumed that commercial and institutional buildings are fairly airtight and that envelope air leakage does not have a significant impact on energy consumption and indoor air quality in these buildings. Furthermore, it is assumed that more recently constructed buildings are tighter than older buildings. However, very little data is available on the airtightness of building envelopes in commercial and institutional buildings.
This report is from a study of the performance of eight exhaust systems of a large medical center in Tennessee. The mechanical contractor of the project initiated this study when confronted with a claim of unacceptable deficiencies in all building exhaust systems. These systems were reportedly exhausting 32% to 43% less than design airflow as a consequence of excessive leakage in the duct system.
The air leakages can have a large impact on heating needs and thermal comfort in industrial buildings. This is sometimes poorly taken into account, both due to the lack of theoretical approach and knowledge of air tightness.
Includes sections on modelling and control algorithms, equipment and envelope characteristics, ventilation performance and building airtightness, ventilation strategies and pollutant transport, NATVENT - overcoming technical barriers, and cooling and indoor air quality in commercial and public buildings.
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