This paper briefly discusses the application of zoned pressurization in buildings and how it is being accomplished. Special emphasis regarding control requirements commonly found in clean rooms, hospital operating rooms, toxicology facilities, wet chemistry labs, or buildings of other demanding constraints are presented and discussed. The two basic control methodologies, flow tracking and differential space pressurization, are presented, and the contrasting differences between the two types of control schemes are discussed. Test results associated with a few limited situations wherein zoned pressurization has been accomplished in facilities are presented by examples of the two methodologies.

Units: I-P