Conference Agenda

Most studies on indoor environments and productivity have been conducted in controlled, static conditions often not representative of the real world. This paper uses a case study-based, real-world approach to empirically investigate the relationship between the indoor environment and workplace productivity in a mechanically-ventilated office environment in southern England. Evidence gathered during a baseline period is used to implement an intervention (limiting peak temperature) with the aim of improving productivity. Environmental parameters (temperature, relative humidity and CO₂) were monitored continuously. Transverse and longitudinal surveys recorded occupant perceptions of their working environments, thermal comfort and self-reported productivity, while performance tasks objectively measured productivity. Although the building was operating within narrow temperature, RH and CO₂ bands, productivity was perceived to decrease when occupants were thermally uncomfortable and when they perceived the air as stuffy. Correlations with perceived changes in productivity were stronger for the perceived environment than for the measured environmental conditions. In addition, test scores were found to decrease at higher temperatures. Median scores were 16% lower for tests conducted when CO₂ levels were in the 1000-1200ppm range compared to those conducted below 800ppm. Insights from the study can be used to optimise indoor office environments to improve staff productivity.

The US Green Buildings Council (USGBC) has created a market transformation program led by a certification process to promote, build, and renovate buildings into LEED™ rated green facilities. One of the goals of the LEED rating system is to reduce carbon and energy expenditure in buildings while improving occupant’s health and wellbeing. Due to a lack of systemic evaluation of buildings undergoing this certification process, however, the effects of this program on building resource utilization, indoor comfort, and occupant’s well-being remain contested. This paper reports on a cross-sectional survey study that investigates discrepancies between LEED certified buildings credits achieved as well as predicted and actual performance. The survey assessed 14 buildings, matched in pairs of two, of LEED and non-LEED buildings. Resource consumption and indoor environmental quality were assessed between both building pairs and their relationship to the LEED certification credits achieved. Results show that while LEED buildings outperformed their non-LEED comparatives, their resource consumption, however, exceeded their predicted expectations in most categories. In addition, the amount of credits achieved were not directly related to better performance. The paper concludes with a framework to integrate occupant feedback and building performance into the way we design, deliver, and operate buildings.

There is an urgent need for construction systems that enable the recovery of materials at the end of a building’s life. The current widespread use of adhesive-based fixings and single-life materials formed from petrochemical derivatives has led to the unprecedented generation of toxic material waste. Consequently, up to 40% of global waste is estimated to come from the construction sector. This design-led research study examines the potential of new light timber frame designs to facilitate material recovery. The research focuses the geometric and jointing properties of the components within the light timber frame and their potential for reuse. To validate the success of the proposed design ideas, a lifecycle assessment of the product was undertaken. This has been supported by a detailed discussion of the durability performance of the system. The study finds that the geometric and assembly conditions of the frame significantly increase long-term sustainable measures. The proposed design is estimated to represent a 70% reduction in embodied energy over an extended product’s lifetime versus conventional light timber platform framing.

The multiple criterion scale developed by Hopkinson is extensively utilised to analyse the subjective degree of discomfort due to glare. Using a luminance adjustment procedure, the brightness of a glare source is adjusted to reveal four levels of discomfort, typically: just imperceptible, just acceptable, just uncomfortable, and just intolerable. In many experimental studies, observers are requested to attend to each level of discomfort in ascending order, from the lowest to the highest criterion. There are, however, reasons to believe that assessments made using adjustments might be affected by the initial anchor, i.e. the setting of the variable stimulus before an adjustment is made, and by order effects, this influencing the reported thresholds of discomfort. To investigate anchor bias and order effects, two Hopkinson-like multiple criterion adjustment experiments were performed, respectively with three different initial anchors and three order sequences (ascending, descending, and randomised). The results revealed substantive bias due to anchor and order effects, primarily at lower glare criteria. This demonstrates the need for caution when interpreting subjective evaluations of discomfort due to glare and estimating the robustness of glare indices derived from studies that used models fitted to data obtained with Hopkinson’s multiple criterion scale and luminance adjustment procedure.

Occupant exposure to unhealthy Particulate Matter (PM) in naturally ventilated air-tight dwellings is not fully understood. In the UK, past studies have not investigated PM in bedrooms. Yet, PM is considered the most toxic pollutant and affects more people than any other pollutant; and bedrooms are the spaces that people typically occupy for the longest cumulative periods of their lifetime; with little or no control of ventilation during sleep. This paper evaluates monitored PM10 and PM2.5 in the context of occupant health in bedrooms of eleven dwellings across Scotland. It focuses on PM2.5, the size associated with greatest impact on health. PM and window operation were monitored concurrently. Air-tightness, smoke tests, dwelling inspections, occupant surveys, questionnaires, and interviews were also conducted. The results indicate that PM2.5 concentrations were generally above the recommended limits by WHO; and potentially unsafe in all the dwellings in the context of the EU-ESCAPE study. Bedtime mean concentrations were significantly lower than the 24hr mean, but would also have potentially negative health impacts based on the ESCAPE study. This suggests possible health burdens of particulates in bedrooms, with continuing construction of air-tight dwellings. Further work is needed on a larger sample of dwellings across different seasons.

Construction of low-cost housing in Colombia is one of the greatest social challenges of the country. Due to Bogotá's climate conditions at 8500 ft. of altitude and non-adapted materials to local conditions, the temperature of these state-subsidized dwellings is usually below optimum comfort standards. This research analyzes the effect of the use of certain types of materials on temperatures, comparing the effect of some traditional building skin– composed by brick and concrete - with a new wall envelope made of recycled elements. A comparative study was carried out by housing typologies, based on a work of measurement of the temperatures inside 16 individual dwellings.

The simulations in design builder to compare the traditional brick envelope material vs a compacted plastic brick, the results suggests that the construction of dwellings with traditional materials such as brick blocks and prefabricated concrete blocks may not provide the best conditions of thermal comfort. Alternative materials made of recycled plastic can represent a cheaper, ecological and comfortable solution. Findings could be of interest to construction stakeholders for the low-cost housing construction in resilient cities, within the framework of a new plastics economy.

Key words: Social housing, thermal comfort, envelope, architecture, recycled materials, energy efficiency.