Post-occupancy evaluation of 20 office buildings as basis for future IEQ standards and guidelines

Abstract

The design of modern work environments must anticipate high levels of spatial and technological change by providing responsive thermal and air quality delivery systems. Building occupants will require indoor environmental conditions to support computer-intensive activities as well as paper-based tasks. However, the current standards and guidelines for indoor environments were predominantly developed without consideration for these modern office variables. This limitation may lead to an occupant's dissatisfaction with the indoor environmental quality (IEQ) as well as unnecessary energy use. With support from the U.S. General Services Administration, a research team at Carnegie Mellon University performed a wide range of post-occupancy evaluation studies in Federal office buildings across the U.S. over 7 years. IEQ conditions were determined with spot and continuous measurements, while the building occupants’ satisfaction with environmental attributes was surveyed simultaneously. Statistical analyses of over 400 workstations linked characteristics and environmental qualities to occupants’ satisfaction. The results challenged the validity of current IEQ standards and guidelines. Specific recommendations for improving current standards and guidelines are outlined here to help enhance environmental conditions in workplaces for future design projects. These include raising summer temperature set-points, separating task and ambient lighting requirements, and establishing minimum air flow rates at each workstation.