As the roll-out of the Covid-19 vaccine offers fresh optimism that the end to the pandemic may be in sight, its prolonged distribution means that the virus continues to present a major challenge to the functioning of urban and architectural systems – as well as economic, industrial and societal ones – worldwide. We can also be certain that when people do return to their places of work in significant numbers, they will be much more aware of how the buildings they occupy affect their health.
The disruption caused by the pandemic has highlighted the centrality of built spaces in our lives – from the home, which has become an almost total presence in our architectural experience, to the workplace, which has been transformed in the search for appropriate social distancing, and the city, which is seeing change from urban transport networks to local highstreets. We have become more conscious of our built environment at every scale.
This is an opportunity for designers and engineers to discuss with clients important human and health-focused topics related to indoor environmental quality, and to promote innovative approaches, such as distributed ventilation, advanced sensing and smart controls, that can support sustainability, flexibility and wellbeing in the built environment.
The fundamental changes to how we interact with buildings are, in many cases, advancing trends that were already established. In other ways, the pandemic is acting as a brake or forcing a rethink of principles that were the norm. For example, the prioritisation of health and wellbeing, remote working, online deliveries and the use of digital technology have continued to increase in importance, whereas spontaneous meetings and interactions with others is now discouraged. The virus has upended the increasing expectation that the workplace be a place that fulfils larger societal and wellbeing functions: a hybrid space blurring the boundaries between life and work, a place of deeper connection, identity, sociality and experience.
Given this acceleration in some areas, and reversals in others, the development of environmental strategies is at an interesting crossroads. Over the past few months, the Environmental Engineering group at Foster + Partners has been exploring how these developments will affect our industry and others worldwide. Undoubtedly, each project will be unique, but what remains foundational is that the quality of our environmental design is based upon a renewed understanding of human health and wellbeing.
The most effective environmental strategies have always been tied to occupant wellbeing by both definition and design. After the Covid-19 crisis, this will continue to be as important as ever, not only at the inception of a project but throughout its lifecycle. The more agile approach to living, work and leisure space developed during the pandemic – a hybrid of remote and physical interactivity – could become even more digitally driven as communication technologies continue to advance. The questions then arise: why return to our shared physical spaces, like the workplace, when we've made the adjustment to a virtual, decentralised one? Why not invest in a wholly digital future?
If we choose to shift our investment from designing places towards virtual substitutes, we stand to lose the rich potential for shared environments to support the thriving of individuals. We must balance real estate savings and commute reductions with emerging evidence of the psychological and physical strains associated with isolating activities, such as homeworking. Is long-term distancing really a direction that supports social and environmental sustainability, with human wellbeing at its heart?
We must, therefore, use this opportunity to expand our conceptions of sustainability in our shared environments. At present, common sustainability strategies, typified by ‘green’ building rating systems such as LEED or BREEAM, aim to reduce the environmental footprint of buildings, but their focus is limited towards resource efficiency.
However, the pandemic has heightened a wider appreciation – and responsibility – for our health and our shared spaces, down to the common air we breathe within our buildings and beyond. For example, the wellbeing benefits of natural ventilation – the process, akin to a building ‘breathing’, that draws in fresh air and expels stale air – and its ability to combat the viral transmission of Covid-19 is negligible if the outside air itself is unfit for human health.
Some international building standards are prioritising health and wellbeing, however. Both WELL and FitWel, for example, have launched safety ratings on disease prevention and management. It may be that, in the future, construction projects will be subjected to official pathogen control requirements.
Many of the measures considered to prevent the transmission of Covid-19 can have a wider positive impact on the overall health and wellbeing of building occupants. Measures that would have been considered prohibitively expensive and unnecessary, such as enhanced filtration, sensing or smart technologies, may now be prioritised by clients, engineers and architects.
One positive collateral effect of the pandemic has been the resurgence of active modes of transport and circulation as people seek to avoid being in tight spaces such as buses, trains or lifts. An uptake in cycling has already been recorded and is expected to increase as cities around the world improve active mobility infrastructure and we slowly return to our workplaces. Equally, the avoidance of lifts as means of vertical transportation can encourage us to take the stairs as an alternative. All of which has a positive impact on mental and physical health.
However, these trends also present their own challenges. How do we maintain clean and healthy conditions in post-commuter services (changing rooms and storage areas), or how do we navigate tall buildings when stair use is impractical? Implementing novel designs and technologies will be a critical factor in providing practical measures in support of occupant safety. Designers will also need to address occupants’ perception of safety within the built environment; especially within shared spaces such as the workplace. It will be important that engineers and architects work together to find creative solutions that enable occupants to both be, and feel, safe.
Improving air quality has been a growing theme within the architecture and engineering industries in recent years and this trend is likely to be accelerated by the current health crisis. The spread of airborne pathogens – such as the Sars-Cov-2 virus – throughout the built environment is intrinsically connected to the design and operation of ventilation systems – the most recognisable of which is the mechanical air-conditioning unit.
Health and wellbeing issues – especially those connected to ideas of fresh air and natural light –have redefined architectural design in the past; most notably, in response to the tuberculosis health crisis at the beginning of the twentieth century. The sanatoria designed by architects such as Alvar Aalto placed their emphasis on cleanliness, sunlight and outdoor space. They were typified by geometric designs, expansive glazing, light and white-washed surfaces, and roof terraces replete with cruise ship-style railings and access to fresh outside air.
However, these pioneering features would become hallmarks not just of sanatoria but of much that we now define as modernist architecture. As the Princeton professor Beatriz Colomina writes in her book X-Ray Architecture, the architectural style of the arch-modernists was ‘unambiguously that of the hospital.’
Looking back further, in London the cholera epidemic of the mid-nineteenth century spurred the reclamation of the city's river from an open sewer into an enjoyable urban waterway, leading to a system of modern sanitation and the revitalised Thames Embankment.
Around this time, a group of healthcare professionals and architects in England, famously including Florence Nightingale, popularised the ‘pavilion principle’ for hospital design, which had originated in France in the eighteenth century. This standard advocated for greater separation between patients and natural ventilation in the wards.
Part of the clean river’s civic renaissance, St Thomas's Hospital on the Albert Embankment, wholeheartedly embraced these principles. Designed in the Italianate style by Henry Currey, courtyards divided the hospital’s wings, or ‘pavilions’, and allowed wards to have large windows that encouraged fresh air to circulate.
Today, the positive effects of well-ventilated and daylit spaces are more thoroughly understood and are partly addressed in sustainable rating systems, which now include guidelines for ‘improving ventilation and filtration, using low-emitting materials, … improving thermal and lighting conditions, and offering daylight views.’
Higher ventilation rates and the use of 100-per-cent-outdoor-air schemes, in place of mechanically ventilated recycled air, can be expected to reduce the concentration of viral material in our buildings, along with other pollutants such as dust, allergens and harmful volatile organic compounds (VOCs).
Research already indicates that increased fresh air rates and improved indoor air quality – providing more thermal variation, gentler transient air flows and fresher air – brings wellbeing benefits, provides a more stimulating environment and improves productivity. Yet, despite evidence for the benefits of natural ventilation, it is much less widely adopted than other ‘green’ strategies.
However, there is often a tension between improving environmental quality, reducing energy consumption and cost. While increased fresh air rates may be manageable in some temperate climates, in more cold or humid areas the energy penalty can be significant. Where natural ventilation is not possible, improved filtration and decontamination systems, and changes to the way spaces are heated and cooled, can play a role in occupant safety and wellbeing in the wake of the pandemic. These design decisions are not always clear cut.
Foster + Partners has been preoccupied with creating ‘sustainable’, people-centric buildings long before they were known as such. Most notably in early projects such as the unbuilt Country Offices for Fred Olsen in Norway, studies for the Island of Gomera, and the Willis Faber & Dumas headquarters in Ipswich.
Today, our bespoke sustainability framework helps evaluate projects in a holistic manner. Based on ten themes – wellbeing, community impact, energy and carbon, mobility and connectivity, resources, water, land and ecology, social equity, planning for change and feedback – the framework goes beyond the focus of most ratings systems. These themes, we believe, must be analysed together, and studied over the whole life cycle of a building.
Flexible and forward-looking, Apple Park, which features the ‘world’s largest natural ventilation system’, sits low amid tall trees, draws its energy from the sun and brings the invigorating views and fresh air from the park through its all-glass facades.
Creating spaces that are directly connected with the fresh air outside is a promising approach to controlling pathogen transmission through enhanced ventilation rates. However, effective implementation requires complex design work and modelling. Great care must also be taken to both understand air movement within the building and to balance the impact on energy performance.
The Bloomberg building also eschewed over-reliance on mechanistic, steady-state environments in favour of fresh air. The pioneering decision to use natural ventilation – a first for a deep-plan office building in the heart of London – required an enormous leap forward in technical design and simulation.
Despite these and other successful efforts, the feasibility of natural ventilation depends strongly on the limitations of the local climate, building height, facade design and cost. However, priorities may now begin to change.
In cases where conditions do not support natural ventilation, mechanical systems can be designed to provide a more controlled increase in fresh-air flow rates. It is apparent, too, that the transmission of pathogens may relate to internal environmental factors such as temperature and humidity. Controlling these factors closely necessitates the design and installation of mechanical systems.
More research is needed to assess the conditions most suitable to limit the transmission of dangerous diseases but, in many climates, mechanical ventilation may still offer a better balance between energy use and air quality over natural ventilation. There is no one-size-fits-all solution. Indeed, both Apple Park and Bloomberg are mixed-mode; capable of being either naturally or mechanically ventilated. Both adopt the use of radiant heating and cooling through their ceilings because of the thermal comfort and energy-use benefits over traditional fan-based forced-air systems.
Radiant heating and cooling solutions provide temperature control without the need to mechanically recirculate air within a conditioned space, a technique that is likely to limit the spread of pollutants. The main disadvantage of these systems is that they don’t cope well with high thermal loads and humid climates.
In more extreme climates, demand-controlled ventilation may become ubiquitous. This, coupled with a reduced occupant density, may help to mitigate the limitations of radiant systems in humid environments. In addition, there is a clear need for innovative energy recovery systems, which prevent the transfer of contaminants between incoming and outgoing air streams and novel dehumidification technologies, like liquid desiccant, to reach maturity.
The practice has worked closely with Bloomberg to help facilitate the building’s adaptation as a safe environment during the Covid-19 pandemic. As we work with clients and our own staff on a return to places of work and leisure, we continue to develop a repertoire of tactics in accordance with best practice, scientific research and government advice. In the adaptive re-design of buildings, and the design of new ones, there is an opportunity to ensure that these tactics fit into broader strategies of resilience: to create in-built capacities among organisations to confront challenges and disruptions – such as a global pandemic – that may lie ahead.
Segregated mechanical ventilation designs, are a promising trend within the industry in this regard. A resilient method for improved pathogen control, decentralised – or distributed – ventilation would limit the spread of contaminants and provide time for further action to be taken prior to a building-wide risk event.
Today, HVAC (heating, ventilation and air conditioning) systems are often interconnected, rather than segregated, and serve multiple zones within a building. There are practical reasons for this but, given the focus on infectious disease, it will be important to assess the benefits against those of segregated ventilation.
Another example of resilience, dramatically put to the test less than a year after its installation, is the environmental system employed in Foster + Partners’ new health centre for the Cleveland Clinic and Case Western Reserve University (CWRU), completed in 2019. Known as the Samson Pavilion, it embodies a future of integrated and interactive health education, combining two schools of medicine, a school of dental medicine and a school of nursing. Key elements of each school are arranged around a 25-metre- (80-foot-) high central courtyard – the social heart of the pavilion.
The environmental engineering of the courtyard was a particular challenge, given Cleveland’s annual temperature swing of up to 42°C (107°F), and a wide variety of occupancies. Although the team could never have foreseen the specific impacts of the Covid-19 pandemic, the Pavilion’s environmental systems were deliberately specified with enough in-built flexibility and resilience to cope with future changes in function.
In April 2020, during the early peak of the Covid-19 emergency, the building was temporarily repurposed as a surge hospital for the city, with the courtyard providing over 300 beds. As reported in the CIBSE Journal: ‘The building was converted in less than a month and the HVAC systems’ flexibility and capacity meant they hardly needed altering … .’
An integrated approach between architects, engineers and client enabled innovative, energy-efficient and resilient solutions. ‘In the courtyard, the high-volume fresh air displacement ventilation, underfloor thermal systems and high daylight levels have come into their own, providing comfortable and safe treatment areas for any prospective patients.’
We know that the future of engineering, construction and architecture will continue to be shaped by integrated thinking and innovative solutions, as it was at the Cleveland Clinic. At the forefront of this will be the implementation of artificial intelligence, computational design and smart technologies. Their design and use will be further optimised according to generative design, sensors and data collection, which enables more intelligent analyses of occupancy and spatial needs in real-time. But technology is only one factor in design; architectural environments are a dynamic interrelation of the people and processes that comprise a building’s scope.
A key principle in reducing Covid-19 infection rates is to avoid person-to-person viral transmission. Hopefully, the need to maintain social distancing will be a temporary anomaly rather than an ongoing trend. However, it is conceivable that, in response to the mental-health implications of lockdowns, quarantines and isolation, people will be more protective of their personal space in the future.
In the short term, reducing the time we spend in shared spaces – which, by extension, should prevent the build-up of crowds – is important to lower the exposure to virus-transmitting aerosols. Existing technology could be leveraged to support this, and buildings could display information about crowded areas in real-time, direct to a smart phone app, similar to occupancy displays on trains.
A secure digital identity including biometrics and location information, as well as instant communication, can be a useful way to manage access and monitor health. However, although countries like South Korea have been largely praised for their use of technology to track the virus – and its citizens – there are privacy concerns in the collection of personal data.
When our presence in a shared space is essential, even if it is socially distanced, we must also look to prevent viral dissemination through contact. We have seen cleaning protocols revised across commercial buildings, increasing in both frequency and strength. While this will undoubtedly limit contagion rates, the selection of disinfection products needs to be carefully considered as these have an impact on air quality and can be a cause of irritation or trigger asthma (unwelcome in the context of a respiratory disease). Going a step further, avoiding unnecessary contact with shared surfaces altogether, through the use of touchless technologies, will not just further prevent the spread of Covid-19, but also other diseases.
Considering ventilation, the Environmental Engineering team is looking towards a future with smarter HVAC controls and the wider use of innovative filtration technologies such as ultraviolet, ionisation or electrostatic filters. It will be important for our engineers to ascertain the most energy-conservative approaches in each case and whether well-timed, intermittent use can achieve effective results, for example.
Chemical disinfection may be another avenue of exploration, wherein ventilation systems perform self- and room-purge cycles at times of heightened risk. The air quality implication of this still needs to be explored. However, ongoing developments in sensor technology are likely to aid in these endeavours.
In order to be most effective against dangerous contaminants, with minimal impact on system energy performance, environmental systems must know when a contaminant is present. Currently, detection of viral contaminants is not feasible within air handling plants, however many tests for the presence of viral RNA (ribonucleic acid) on surfaces are available in laboratories. We expect to see a renewed focus in this field, which may translate this technology into our HVAC systems.
While the disruption caused by the pandemic is daunting, it is not unprecedented. It can be seen as part of a larger history from which we can usefully learn. In this history, epidemics and disease can be positive drivers of innovation, advancing design solutions and aesthetic movements that reflect our ability not only to adapt to catastrophe, but to improve conditions for people and societies in its wake.
As Norman Foster said in his interview with the United Nations, in the wake of disruption ‘historical precedent shows that cities have the opportunity to be transformed to being safer, more beautiful, quieter, cleaner, healthier – greener in the most literal sense.’
Our environmental response to the Covid-19 emergency must, therefore, be seen as an opportunity to advance the sustainability agenda.
The return to offices and other shared spaces throws into sharp relief the relationship of our internal environments to larger infrastructures, such as work, housing and transportation. We should consider this an opportunity to radically re-imagine their relationship and take a broader look at the health of our buildings’ users and the planet, and see them as an integral part of the environmental engineering ecology. The size of our practice and the range of its disciplines enables the Environmental Engineering group to leverage this diverse skill base and take a truly holistic approach to the challenge of Covid-19 and build for resilience beyond it.
Through a collective experience of crisis and uncertainty, there is a sense that we are globally united in this struggle. Now is the time for building designers to reaffirm commitment to designing resilient, sustainable and healthy buildings that will serve generations to come.
06 May 2021
Andrew Jackson, Stuart Humber, Ines Idzikowski, Kyle Thompson
Andrew Jackson, Stuart Humber, Ines Idzikowski and Kyle Thompson are members of the Environmental Engineering group at Foster + Partners. The group was conceived with the fundamental belief that environmental systems must be conceptualised in harmony with the architecture to support sustainable development. The team’s work encompasses MEPF engineering, sustainable environmental design, analysis and masterplanning, architectural lighting design, vertical and horizontal transportation, and infrastructure engineering.