13 October 2016 | Martin Read
Making the case for sustainable construction is nothing new. The quest for a more joined-up approach to construction has been the intent behind various government reports in the past and we seem never to be too far from another such initiative.
This month, delegates from across the world will attend the United Nations Habitat III conference in Quito, Ecuador to grapple with what 'the city' means, and what cities should become in a rapidly urbanising world. Delegates will attempt to devise a 'New Urban Agenda', a programme of principles for future sustainable urban development.
Now, on the face of it this may not sound much of an issue for all those facilities managers dealing principally in the existing built environment rather than the built environment yet to come. But factor in the steady shift in government policy towards a better awareness of life cycle cost, as well as a greater understanding of the wider reach of sustainability through its ever deepening economic and social dimensions, and Habitat III becomes important as an event likely to influence how cities and the organisations situated within them are managed in years to come.
It's no surprise that Habitat conferences do not feature on most FMs' radars, taking place as they do just once every twenty years. And in the past they have typically emphasised the problems associated with human settlements in developing countries. Habitat III, however, is markedly different because it is intended to generate ideas applicable as much to developed countries as those still developing.
Sustainable Development Goals
Originally proposed at the UN Rio+20 summit in 2012 and agreed by UN member states in 2015, the UN's Sustainable Development Goals (SDGs) are perceived to be wide-ranging and ambitious. Most relate to escalating urbanisation, with SDG 11 in particular dedicated to "making cities inclusive, safe, resilient and sustainable".
When the last UN Habitat conference was held 20 years ago, sustainability as a topic barely registered. The world has changed significantly since then, in particular with the speed of urbanisation in the continents of Africa and Asia, and the explosion in information sharing mechanisms (for Habitat II back in 1996, email was in its infancy and the potential of the internet largely unexplored).
The New Urban Agenda cuts across all of the SDGs. The need for sustainable development informs the entire debate about how the world's cities will respond to becoming home to 70 per cent of the world's population by 2050.
Housing and sustainable human settlements - key concepts from earlier Habitat conferences - remain important. But Habitat III is more concerned about the effect on people of cities turning into urban corridors, mega-regions and 'city regions'. The conference will seek ideas to help city governments and those that work with them to harness "the chaotic forces of urbanisation". It will be well worth reading what is agreed in Quito.
Façading the future
As pressure on cities to expand increases, so does the need to make existing building stock more sustainable. In its report, 'Cities Alive – Green Building Envelope,' building engineering consultancy Arup looks at the potential impact that the greening of existing building envelopes could have on the 85 per cent of the buildings that will still be in operation come 2050.
Can green façades reduce energy consumption, improve air quality and help people's well-being in ever more densely populated cities?
"By making use of about 20 - 25 per cent of each building envelope, i.e. façade and roof areas, we could achieve significant benefits to improve the micro-climate in cities," suggests Rudi Scheuermann, a fellow at Arup.
Extended periods of natural ventilation brought about by greened exteriors can reduce the amount of energy required for cooling all year round, giving building occupants "more freedom to control their individual environment by means of healthier and more beneficial natural ventilation".
Better stormwater management, improved biodiversity and the increased absorption of CO2 etc. will follow, argues Scheuermann.
Making the benefits of green envelopes measurable, quantifying rather than merely qualifying benefits as a whole, is key. A clearer cost-benefit analysis needs to be put to cities and the building authorities that serve them, as well as developers and investors, so that they understand how investment in green infrastructure is no longer just "architectural decoration" but an essential, urgently needed element to improve the sustainable operation of buildings with lower energy consumption, and improved and significantly healthier living conditions for cities' inhabitants.
Green façades can affect the wider cityscape in three principal ways - through the dampening of the Urban Heat Island (UHI) effect, by which cities become heat traps; through a reduction in air pollution; and perhaps the most undersold benefit, a reduction in sound levels from emergent and traffic noise sources.
Arup cites research from Gill et al. (2007) suggesting that if Greater Manchester increased its green infrastructure by 10 per cent (in areas with limited or no green cover) it could reduce average temperatures by up to 2.5 degrees centigrade. As an illustration of what can be possible with concerted effort spread across existing buildings, it's a compelling case.
Cool running
"The ability of green façades to reduce the cooling loads on buildings is well known," Arup's report notes. "But what is possibly less well understood is that green façades can improve the air quality in city streets. Plants can remove not only carbon dioxide but also particulate air pollutants such as smoke and dust."
Examples are given of buildings where green envelopes have been designed in from the ground up, with dynamic façades such as the south-facing positioning of panel photobioreactors, generating biomass and heat, on the BIQ house in Hamburg, Germany.
All of which is without even touching upon the aesthetic qualities of green façades and their psychological connotations, particularly where colour of the plants changes as each seasons pass.
Building envelope surfaces can make a far greater contribution to their external environment, the report suggests. They can become a 'default design approach', but for this to happen will require a significant rethink of current design considerations.
Facilities managers feeding in to these discussions could make a powerful difference to those they serve in a world in which the quest for greater sustainability can help put FM in the spotlight.