Trends in urban sustainable experiments and the importance of post-occupancy testing 

GCHU Intern and BA Geography student Juan Garcia Valencia reviews the current experiment trends in urban sustainability.

Juan Garcia Valencia

BA Geography student, University of Oxford

Email: [email protected]

In the recent COP26, the built environment was given 12 months to turn climate pledges into significant action to limit temperature rises to 1.5C. This is because urban infrastructure and buildings are responsible for up to 80% of emissions in some cities, and 28% of the energy-related greenhouse gas emissions globally, highlighting the need to transition away from fossil fuels and adopt green building solution as part of the climate action. However, the International Energy Agency (IEA) has identified the building sector as one of the most cost-effective sectors for reducing energy consumption, with estimated possible energy savings of 1.509 Mt of oil equivalent (Mtoens) by 2050. Moreover, by reducing an overall energy demand and improving energy efficiency, building infrastructure can significantly reduce CO2 emissions from the building sector, corresponding to possible mitigation of 12.6 Gt of CO2 emissions by 2050. To foster the adoption and compliance with energy-environmental policies, and to measure sustainability in the built environment, efficient assessment tools and methods must be adopted and used, like green certification schemes. Current trends in the literature suggests the need for expanding the parameters considers in such schemes to include social and health benefits through the use of post-occupancy testing in urban sustainability experiments.  

Urban infrastructure and buildings have extensive direct and indirect impacts on the environment. During construction, occupancy, renovation, repurposing, and demolition, buildings use energy, water, and raw materials, generate waste, and emit potentially harmful atmospheric emissions. Green building standards, certifications, and rating systems have emerged as tools to mitigate the impact of buildings on the natural environment through sustainable (urban) design. These certifications are intended to outline and establish building standards to ensure they offer an environmental benefit. Urban sustainable experiments in the building sector increased with the launch in 1990 of Building Research Establishment’s Environmental Assessment Method (BREEAM), the first green building rating system in the world, later followed by Leadership in Energy and Environmental Design (LEED) in 2000. Green building certifications are on the rise as market conditions change and the demand for greener products continues to increase.  

Most certification programs assess infrastructure and buildings based on multi-attribute programs, including parameters such as energy use, recycled content, and air and water emissions from manufacturing, disposal, and use. Others focus on a single attribute, such as water, energy, or chemical emissions. More importantly, all certification schemes share common approaches and goals including the environmental evaluation and market recognition of low environmental impact buildings, inspiration to find innovative solutions that minimize the environmental impact, and a system to help reduce running costs, improve working and living conditions. In the face of global warming, the availability and use of sustainable, green certification schemes is constantly increasing, as most certifications attribute 51% of the final score to the environmental dimension, making green and sustainable buildings the main focus. Recent studies have noted the economic importance of such envrionmental certification schemes as they exert an influence on the building market and may directly and indirectly affect cost and savings. Evidence based on the preferences of prospective real estate investors for condominium units in Singapore showed how premium buyers would be willing to pay for property certified by the Green Mark Scheme, suggesting a strong business case for developers of green buildings. Consumers and resident are also shown to significantly value benefits of the energy-saving, sustainable attributes to the point they are willing to pay more, as sustainable design leads to individual energy savings, environmental benefits and even comfort benefits (air quality improvements and noise protection).   

There is a need for certification schemes to include a thorough sociological examination of the effects of urban sustainability experiments in their sustainability assessments, to better adjust, manage and maximise the benefits of building experiments. Urban sustainability experiments aim to optimize, reduce emissions and increase efficiency of systems but do not necessarily enhance social sustainability aspects such as quality of life, physical, social and cultural well-being. Furthermore, the attention to post-occupancy testing tends to be neglected in certifications and sustainability practices; as these relate mainly to the plan, design and construction phases. Therefore, it is necessary to understand how qualities of sustainable urban design can enhance liveability. Adopt a scale-oriented examination to this discussion will help us understand the need for post-occupancy testing at a small (building) scale and larger (urban district) scale.  

A small scale, the construction of green buildings forms part of larger sustainable urban experiments that aim to address social, economic, functional, and technical and environmental problems in the surrounding urban area. Social aspects of buildings have only just begun to gain importance and are still limited in representation in green certification schemes. The current trends in the construction sector are shifting from focusing only on the energy performance of the buildings towards a more holistic approach that covers the whole building lifecycle, such as the use of resources, and includes other aspects, such as the impact on human health. The most well-known certification schemes include Leadership in Energy and Environmental Design (LEED), Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB) and British Research Establishment Environment Assessment Methodology (BREEAM), holding the largest market share (80.6%). These commercial certification schemes were developed as tools to gain a better insight into the performance of a building, through the analysis of parameters such as site, energy, water, indoor environmental quality (IEQ), material, waste, and pollution. Only the IEQ parameter partly considers health and well-being, showing how most certification schemes thoroughly evaluate the sustainability of buildings but fail to emphasise that the health and well-being of the building’s occupants.

Certain certification schemes have been developed to focus solely on topics related to health impacts like Living Building Challenge, created by the International Living Future Institute in 2006 and WELL by the International Well Building Institute, launched in 2014. These are useful to identify the health parameters that should be addressed in depth throughout certification assessments. Indoor air pollution and quality is an important factor to consider given the large amount of time spent indoors- improving indoor environments can improve health of occupants, benefit employees, increase productivity and decrease absenteeism. In fact, the World Health Organization (WHO) published a study in which it is estimated that 1.6 million excess deaths are associated with exposure to indoor air pollutants. Other important parameters include light conditions, as unsuitable lighting can influence the performance, safety and health of occupants. Finally, the role and design of the built environment was identified as significant in greatly contribute to the promotion of human physical activity and fitness. Easily promoted by sustainable building design, bike-sharing schemes demonstrated several benefits, like journey time savings, health benefits and reductions in motor vehicle use, as well as proximity of green spaces which also increase the physical activity of the occupants. 

At the large (urban district) scale, a post-occupancy evaluation (PO) methodology provides a useful lens through which to examine new and existing buildings and provide stakeholders with information about performance and effectiveness of the occupied design environments. A POE aims to fundamentally understand building performance and its socio-economic, environmental, and cultural implications. POEs can go beyond energy efficiency, to evaluate other intangible issues such as productivity, identity, atmosphere, and community, and measure the client satisfaction and functionality. More importantly, the main benefit of POEs is that they allow the provision of information for continuous improvement to make any adjustments that suit the needs of the occupants better. The data for POEs may be gathered from audits of resource consumption, on-site observations, surveys or questionnaires. The certification Leadership in Energy and Environmental Design (LEED) evaluates POE to a certain extent through the Occupant Comfort Survey within the category Indoor Environmental Quality.

The survey intends to evaluate the user’s comfort in topics of acoustics, building cleanliness, indoor air quality, lighting, and thermal comfort. The methodology suggests survey application to rate satisfaction with a seven-point scale, ranging from +3 very satisfied to -3 very dissatisfied. To increase reliability, it is recommended to carry out the evaluation every two years, and to have anonymous responses from over the 30% of the building occupants, in order to generate a document with a corrective action plan. The corrective plan is meant to be focused in the areas with a dissatisfaction rate above 20%. Nordhavn, known as the largest metropolitan development project in northern Europe, serves as an example of a POE at the urban district scale. Currently under development in Copenhagen, this project encourages biyearly neighbourhood meetings to inform and engage involvement from residents, occupants, and associations, providing information about occupant’s concerns and improvements. This led to the creation of Hamburg Square in the Aarhus Street neighbourhood, originally planned without greenery, but due to the people interest, the landscape design plan changed to incorporate increased green features. Other post-occupancy strategies that help to consider health in certification schemes includes survey reports that measure resident satisfaction through phone interviews.  

Most urban sustainable experiments: focus on climate change mitigation and adaptation, have economic influence on the building market, but also impact the health and well-being of residents in the surrounding area. It is essential that green certification schemes, acting as a way to assess the success of sustainability experiments, expand their parameters to include social aspects to help proliferate “green” building that benefit both the environment and the surrounding urban environment.