Critical factors and thresholds for user satisfaction on air quality in office environments

© 2019 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, CO2 and particulates are identified as critical factors for user satisfaction. In particular, the analyses revealed that the CO2 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

Leveraging ubiquitous computing as a platform for collecting real-time occupant feedback in buildings

Building occupants represent a rich source of information for evaluating environmental design practices and building operations.  This paper presents a scalable diagnostic technology for collecting real-time Indoor Environmental Quality (IEQ) feedback from building occupants: an interactive desktop polling station. The device demonstrates the potential of ubiquitous computing, a model of human-computer interaction in which information processing is integrated into everyday objects, to engage occupants in providing IEQ feedback in real work environments.  Example data from a field study of a high-performance office building are presented demonstrating the applicability of multiple devices to acquire detailed feedback over daily and seasonal variations in climatic conditions.  Sample results show how polling station data can help identify the frequency and magnitude of discomfort with the spatial and temporal granularity needed to assess, validate, and improve the performance of environmentally responsive building technologies, controls, and design strategies. Analysis of repeated-measures subjective assessments paired with concurrent physical measurements is performed to demonstrate how existing standards and assumptions for occupant comfort could be evaluated and refined using detailed occupant feedback from buildings in use.  Results are discussed regarding implications for improving decision-making for the design, certification, and operation of environmentally responsive buildings

Global relevance of total building performance

Global population and environmental trends demand a radical departure from current building and developmental processes. Applying total building performance thinking can reduce energy consumption, pollution and waste in existing and new construction by a factor of 4 and simultaneously can improve quality of life within buildings--measured through occupant satisfaction, health and productivity. The further development of advanced energy and water systems, and the application of appropriate technology and systems integration concepts will help to enable the elimination of `waste-streams', avoiding obsolescence, as well as managing industrial and agricultural nutrient streams. Instead of treating buildings and their contents as `pre-garbage', worse `pre toxic-waste', all material flows can be considered within life cycles for `cradle to cradle'use. These concepts can make major contributions towards the creation of more sustainable lifestyles with even greater quality in the industrialized countries and the development and implementation of sustainable urban and building infrastructures in rapidly emerging economies. Rather than the continued export of non-sustainable building solutions, this paper argues for the development and demonstration of such practices in the industrialized countries that would create a progressive'pull'to enable the appropriate implementation of new practices.

Vector Field Representation for the Evaluation of Multiple Performance Variables

A vector field representation is proposed to simulate the spatial distribution of four building system performance variables: light, sound, radiant heat, and air flow. From this simulation, a measure of the impact of adding, deleting, or modifying an object in the field is computed. This measure serves as a passive evaluation of the user/designer's decision to modify the location or dimensions of the object in a space. This process of simulation-evaluation is performed by a performance module (PM), which is viewed as a component of a CAAD System (Computer Architectural Aided Design). This paper describes the motivation, objectives, methodology and preliminary results of the approac

An integrated approach to design and engineering of intelligent buildings--The Intelligent Workplace at Carnegie Mellon University

In the past few years, there have been significant advances made in the design and engineering of “intelligenti workplaces, buildings that not only accommodate major advances in office technology but provide better physical and environmental settings for the occupants. This paper will briefly present recent approaches to the creation of innovative environments for the advanced workplace. The architectural and engineering advances demonstrated in Japan, Germany, North America, the United Kingdom, and France can be summarized in four major system categories: (1) enclosure innovations including approaches to load balancing, natural ventilation, and daylighting, (2) heating, ventilation and air-conditioning (HVAC) system innovations including approaches to local control and improved environmental contact, (3) data/voice/power “connectivityi innovations, and (4) interior system innovations, including approaches to workstation and workgroup design for improved spatial, thermal, acoustic, visual, and air quality. In-depth international field studies of over 20 intelligent office buildings have been carried out by a multidisciplinary expert team of the Advanced Building Systems Integration Consortium (ABSIC) based at Carnegie Mellon University. ABSIC is a university-industry-government partnership focused on the definition and development of the advanced workplace. The ABSIC field team evaluated the component and integrated system innovations for their multidimensional performance qualities, through expert analysis, occupancy assessments, and field diagnostics.  Based on the results of the case studies and building on the most recent technological advances, the ABSIC team developed the concepts for the Intelligent Workplace, a 7000 square foot living laboratory of office environments and innovations. This project is now under construction at Carnegie Mellon University and its features are discussed in the second section of this paper.