Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have shown that these seals tend to fail over time periods ranging from days to years. We have used several test methods over the last few years to evaluate the longevity of duct sealants when subjected to temperatures and pressures representative of those found in the field. Traditional cloth duct tapes have been found to significantly under-perform other sealants and have been banned from receiving duct tightness credits in California's energy code (California Energy Commission 1998). Our accelerated testing apparatus has been redesigned since its first usage for improved performance. The methodology is currently under consideration by the American Society for Testing and Materials (ASTM) as a potential new test method. This report will summarize the set of measurements to date, review the status of the test apparatus and test method, and summarize the applications of these results to codes and standards.

This report summarizes the major findings from a field study of the Region 8 Headquarters building for the Environmental Protection Agency (EPA) in Denver CO. This report constitutes one of three case studies we are conducting. The overall goal of these studies is to collect whole-building performance data from selected operational buildings that are using underfloor air distribution (UFAD) as their primary means of space conditioning. By conducting a series of field investigations, the overall performance of underfloor air distribution (UFAD) buildings can be assessed with a consistent protocol that includes collecting data from utility-bills, occupant surveys, performance data from an advanced portable measurement cart, plus other available information on design, commissioning, operations, and lessons learned from conditions in the field. To conduct such case studies, CBE developed a performance assessment protocol [Bauman 2008] that includes the approaches that are briefly described below; the respective key findings accompany each discussion. A glossary of the UFAD terms used in this report is included in Appendix C.

The bar was raised high for the building, also known as Block 225, before construction began. The California Department of General Services wanted a green building, and the design-build team set a goal of achieving LEED Gold certification — a relatively new green standard in 1999.

Block 225 is the first California state office building to use an underfloor air-distribution system and is the first design-build office building in the state’s history. The integrated approach to design and construction resulted in the building’s completion 10 months ahead of schedule. The design-build team and Department of General Services blazed a trail for all future statedeveloped projects.