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BACKGROUND: The elements that contribute to a healthy building are multifactorial and can be discussed from different perspectives. OBJECTIVES: We present three viewpoints of designing a healthy building: the importance [...]

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. [Copyright &y& Elsevier]

Abstract: This paper investigates the effects of occupant gender and age on thermal satisfaction in office environments. The data used for the analyses was collected from 40-sampled occupants and their workstations on 38 floors in 20 office buildings in the U.S. with support from the U.S. General Services Administration. The field measurements include data collection for air temperature, radiant temperature, temperature stratification, relative humidity and air velocity of the sampled workstations. Occupant satisfaction surveys were distributed to each occupant in the workstations measured, and the thermal attributes of building systems were recorded. The objective and subjective data sets support statistical correlation analysis between environmental qualities and user satisfactions. The statistical analysis of air temperatures, occupant thermal satisfaction, age and gender revealed that females are more dissatisfied with their thermal environments than males especially in the summer season with high significance, and occupants over 40 years old are more satisfied than under 40 in the cooling season with marginal significance. [Copyright &y& Elsevier]

Indoor Air Quality (IAQ) of the workplace is highly linked with occupants' health, comfort and satisfaction. To maintain the good IAQ of buildings, Post-Occupancy Evaluation (POE) is often combined with environmental measurements to holistically examine existing performance conditions in relation to occupants' satisfaction. The Center for Building Performance and Diagnostics (CPBD) at Carnegie Mellon University conducted post occupancy evaluations for over 1600 workstations in 64 buildings using the National Environment Assessment Toolkit (NEAT)—a suite of three tools for workstation IEQ measurements, Technical Attributes of Building Systems (TABS) and occupant satisfaction surveys. The rich dataset generated by NEAT was employed in this study to perform multivariate regression and multiple correlation coefficient analyses on IAQ. We examine the relationship between measured and perceived IAQ indices, as well as interdependencies between IAQ indices and occupant satisfaction variables of significance. Among measured IAQ indices, CO 2 and particulates are identified as critical factors for user satisfaction. In particular, the analyses revealed that the CO 2 threshold of 582 ppm is the highest occupant satisfaction in office buildings. To ensure good air quality in office buildings, our findings recommend "Operable window", "Dedicated exhaust", "Individual return air diffuser density" and "Low/medium partition height" as applicable design guidelines. Through this study, we demonstrate the effectiveness of integrating POE with environmental measurements to systematically develop a rich database leading to critical thresholds and design guidelines for highest occupant satisfaction. • Provides practical IAQ assessment methods and procedures centered on the occupants' perspective. • Reveals air quality features in the office environment, and defines correlations between occupant perception on air quality and measured data. • Prioritizes critical features on IAQ evaluation in the field to enhance occupant satisfaction. • Proposes metrics and guidelines for IAQ standards that capture new thresholds that impact building occupants' satisfaction on air quality. • Provides design guidelines and maintenance and operation protocols for designers, building owners and facility managers. [ABSTRACT FROM AUTHOR]

Abstract: An integrating air-handling unit (IAHU) control theory has been proposed to improve the energy efficiency in office buildings by utilizing the regional and operation differences among multiple AHUs. Unlike the conventional AHU operation, where the units are controlled as independent systems without interaction, IAHU coordinates the AHUs based on the dynamic outside air conditions and system operation modes to achieve synergized energy performance and maintain the indoor air quality. The synergization strategy allows the outside air intake and the airflows to be orderly re-allocated among the AHUs when conditions are appropriate. This paper presents the implementation methodology and performance evaluation of IAHU in an open-plan office building with multiple AHUs. The allocation of airflows among the AHUs is described first to illustrate how IAHU deals with multiple AHUs in a building. The supervisory level control algorithm is then detailed and easy-to-follow flowcharts are provided based on the decision-making schema. A two-step hourly evaluation method and the energy simulation model are introduced. An office building with multiple AHUs is selected to assess the performance of IAHU. The study concludes that the innovative IAHU with the easy-to-implement strategy can be readily implemented to achieve high energy efficiency in open space office buildings. [Copyright &y& Elsevier]