Leena Thomas

Leena Thomas


Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2016 in Building and Environment
Verified
Journal Article
Open access
Sanyogita ManuSanyogita Manu
Sanyogita Manu
YSYash Shukla
Yash Shukla
RRRajan Rawal
Rajan Rawal
LTLeena Thomas
Leena Thomas
RDRichard de Dear
Richard de Dear
India is witnessing unprecedented growth trends in building construction, particularly office spaces. Indian offices are designed to operate at 22.5 ± 1 °C all year round to meet the stringent “Class A” specifications outlined by international standards in the absence of an India-specific comfort standard. This paper proposes an India Model for Adaptive Comfort – IMAC – based on the field surveys administered in 16 buildings in three seasons and five cities, representative of five Indian climate zones. A total of 6330 responses were gathered from naturally ventilated, mixed mode and air-conditioned office buildings using instantaneous thermal comfort surveys.Occupants in naturally ventilated Indian offices were found to be more adaptive than the prevailing ASHRAE and EN models would suggest. According to the IMAC model, neutral temperature in naturally ventilated buildings varies from 19.6 to 28.5 °C for 30-day outdoor running mean air temperatures ranging from 12.5 to 31 °C. This is the first instance where a study proposes a single adaptive model for mixed mode buildings asserting its validity for both naturally ventilated and air-conditioned modes of operation in the building, with neutral temperature varying from 21.5 to 28.7 °C for 13–38.5 °C range of outdoor temperatures. For air-conditioned buildings, Fanger's static PMV model was found to consistently over-predict the sensation on the warmer side of the 7-point sensation scale


19 January 2015 in Building Research & Information
Verified
Journal Article
Closed access
Christhina CandidoChristhina Candido
Christhina Candido
Jungsoo KimJungsoo Kim
Jungsoo Kim
RDRichard de Dear
Richard de Dear
LTLeena Thomas
Leena Thomas
Research findings point to three methodological shortcomings of current post-occupancy evaluation (POE) tools: (1) contextualizing results, (2) adding instrumental data side by side to survey results and (3) producing meaningful feedback to its key stakeholders. This paper introduces the holistic BOSSA (Building Occupants Survey System Australia) and tools developed under this project's scope in close collaboration with industry. It aims to present and discuss the statistical analysis used in the BOSSA tool, distilling the survey results down to nine indoor environmental quality (IEQ) dimensions and their association with four overall indices. Principal component analysis (PCA) extracted nine IEQ dimensions that were uncorrelated with each other: spatial comfort, indoor air quality, personal control, noise distraction and privacy, connection to the outdoor environment, building image and maintenance, individual space, thermal comfort, and visual comfort. Four separate multiple regression analyses were conducted, one for each global evaluation item as an independent variable: work area comfort, building satisfaction, productivity and health. This statistical analysis provided the rational basis of BOSSA's scoring system, designed to simplify how occupant survey results are communicated to key stakeholders from the property industry and researchers.

4 June 2018 in Building Research & Information
Verified
Journal Article
Closed access
Christhina CandidoChristhina Candido
Christhina Candido
LTLeena Thomas
Leena Thomas
Shamila HaddadShamila Haddad
Shamila Haddad
Fan ZhangFan Zhang
Fan Zhang
MMMartin Mackey
Martin Mackey
WYWei Ye
Wei Ye
Activity-based working (ABW) provides office workers with a variety of indoor workspaces purposively designed to accommodate different tasks. Despite an increased use of ABW, studies focusing on its impact and the resultant office design are yet to follow suit. This paper addresses this knowledge gap by providing empirical evidence from studies conducted before and after relocation from contemporary open-plan offices to ABW spaces. Results from post-occupancy evaluation (POE) surveys (n = 896 responses), spot measurements of indoor environmental quality (IEQ) and step-count monitoring (one case study; n = 20 participants) before and after relocation are reported. A total of 10 workspaces participated (six combi and four ABW) in this study. Design features were documented and analyzed. While there were limited differences in the measured IEQ conditions between office layouts investigated here, ABW workspaces yielded significantly higher satisfaction results on key IEQ dimensions, perceived productivity and health. Office layout was also found as a significant (or nearly significant) predictor of occupants’ lightly active and sedentary time but did not affect occupants’ daily step counts and distance they travelled. These results highlight the significance and impact of office layout and human-centred approach to design on occupants’ satisfaction, perceived productivity and incidental physical activity opportunities.

5 October 2010 in Building Research & Information
Verified
Journal Article
Closed access
LTLeena Thomas
Leena Thomas
Existing buildings present the best opportunity for reducing greenhouse gas emissions in developed economies, given that only 2–3% of the building stock is newly built each year. Insights from a post-occupancy evaluation of a large-scale refurbishment project of a head office building in Sydney, Australia, are presented to inform future refurbishment strategies. The study evaluates occupant satisfaction and energy performance, and elicits influencing factors arising from the design process and interventions, ongoing building management, and operational performance. Occupants returned a high level of satisfaction across the range of environmental variables for overall comfort, temperature, lighting, and air quality as well as perceived productivity and health. These outcomes highlight the importance of improving indoor environmental quality for occupants particularly through increased fresh air, daylight, glare control, access to views, and noise management. The positive results reinforce the value of an integrated and user-responsive approach that was adopted for building design, development, and management. The reduction in operational energy (in this project, coupled with carbon reduction) as a consequence of refurbishment and positive user feedback demonstrates the potential to future-proof existing buildings in the context of climate change. Les bâtiments existants offrent la meilleure possibilité de réduction des émissions de gaz à effet de serre dans les économies développées, étant donné que les constructions neuves ne représentent chaque année que 2 à 3% du parc bâti. Les enseignements retirés d'une évaluation après occupation d'une opération de rénovation à grande échelle réalisée dans l'immeuble d'un siège social de Sydney, en Australie, sont présentés afin d'infléchir les futures stratégies en matière de rénovation. L'étude évalue la satisfaction des occupants et les performances énergétiques, et met au jour les facteurs d'influence qui découlent du processus de conception et des interventions réalisées, de la gestion en cours du bâtiment et des performances de fonctionnement. Les occupants ont exprimé un degré de satisfaction élevé sur l'ensemble des variables environnementales concernant le confort global, la température, l'éclairage et la qualité de l'air, aussi bien que la productivité et la santé telles qu'ils les ont perçues. Ces résultats mettent en évidence le fait qu'il est important d'améliorer la qualité environnementale intérieure pour les occupants, tout particulièrement en apportant davantage d'air frais et de lumière du jour, un plus grand contrôle de l'éblouissement, un accès accru à des panoramas et une gestion renforcée du bruit. Ces résultats positifs renforcent l'utilité d'une approche intégrée et sensible aux besoins des utilisateurs, telle qu'elle a été adoptée pour concevoir, aménager et gérer ce bâtiment. La réduction de l'énergie de fonctionnement (dans cette opération, conjointement avec la réduction du carbone) en conséquence de la rénovation et du feedback positif des utilisateurs démontre le potentiel de cette approche pour permettre aux bâtiments existants de bien affronter l'avenir dans le contexte du changement climatique. Mots clés: adaptation, changement climatique, confort, énergie, qualité environnementale intérieure, conception intégrée, occupants, évaluation après occupation, rénovation

30 August 2019 in Buildings
Verified
Journal Article
Open access
Ozgur GocerOzgur Gocer
Ozgur Gocer
Christhina CandidoChristhina Candido
Christhina Candido
LTLeena Thomas
Leena Thomas
KGKenan Göçer
Kenan Göçer
This paper reports the results from a dataset comprising 9794 post-occupancy evaluation (POE) surveys from 77 Australian open-plan offices. This paper specifically focuses on a sub-set of 20 offices (n = 2133), identified from ranking 10 offices each, with the least (n = 1063) and highest (n = 1070) satisfaction scores, respectively. The satisfaction scores were evaluated on the basis of seven factors (i.e., building/office aesthetics and quality, thermal comfort and indoor air quality, noise distraction and privacy, personal control, connection to outdoor environment, maintenance and visual comfort, and individual space). Using the POE survey data from 20 offices, regression analyses and two-way ANOVA tests were carried out to understand the differences in occupants’ satisfaction and perceived productivity arising from open-plan offices. According to the statistically significant regression analyses results, it was identified that building/office aesthetics and quality (β = 0.55, p < 0.001) and noise distraction and privacy (β = 0.33, p < 0.001) were the two strongest predictors contributing perceived productivity in low-performance offices. Two-way ANOVA test results for the 10 high-performance offices indicate that the perceived productivity was strongly associated with the office’s physical configuration, the employees’ working experience, and the working hours at that office.