Architects must not hide the carbon footprints of their buildings
Sustainability in practice: Architects should be ashamed of their abysmal record on carbon emissions data, says Hattie Hartman
As the AJ’s sustainability editor, my inbox regularly overflows with emails about projects claiming to be the latest example of low-carbon building. Project descriptions typically enumerate a long list of eco-features and often a BREEAM ‘Excellent’ rating, but how do we assess how green a building really is?
The only meaningful way is to measure energy use. Almost two years ago, the AJ began asking architects to submit annual CO2 emissions data for buildings whose details were due to be published in the magazine. Since then, less than half have provided this data. For those who have, it was often only sent in after insistent phone calls and a flurry of emails to service engineers.
Architects are notoriously bad when it comes to numbers. The profession needs to reachthe point where provision of energy-use statistics becomes second nature, on a par with a building’s cost or its square footage. Best-practice benchmarks for common building types should be a matter of general knowledge.
To deliver low-carbon buildings, we need to become conversant with the nuances of these numbers
Last year, the Chartered Institution of Building Services Engineers (CIBSE) updated its CO2 emissions benchmarks. It is easy for architects to say, in the face of such initiatives, that it is the engineers who ‘own’ the emissions numbers, but architects must at least be familiar with the assumptions underlying the numbers. They must be able to scrutinise their accuracy and know where to make amendments if we are to meet zero-carbon targets.
Understanding the numbers is only the first step. Ensuring their accuracy is critical. Researching a recent feature on healthcare buildings, I found one statistic was way off because the engineer had not divided the annual carbon emissions by the building footprint to provide a square metre figure, and this erroneous information had been submitted to the RIBA as part of an awards submission. No one had noticed. On another occasion, the figures submitted were inconsistent because different fuel conversion factors had been used to convert gas and electricity meter readings to CO2 emissions data, skewing the results by up to 15 per cent.
It’s also important to remember that the emissions data is not actual, only predicted, and it only includes regulated building energy loads, not incidental occupant loads such as emissions generated by IT and catering. Accurate actual emissions data, which is far more useful, can only be obtained after a building has been occupied for at least two years. By then, architects are well into the next contract, so often lose the benefit of feedback knowledge gained from previous projects.
The most comprehensive emissions benchmarking tool was pioneered by Bill Bordass and the Usable Buildings Trust. Loads are broken down into four categories: heating and hot water; cooling, fans and pumps; and lighting. Unregulated loads, including ‘special’ loads such as IT, are also measured.
To deliver low-carbon buildings, we need to become conversant with the nuances of these numbers. To this end, London and Edinburgh-based practice Bennetts Associates recently convened a workshop with half a dozen of its service engineers from different consultancies to compare data from its projects, ensure that it was reported consistently, analyse which buildings performed best and find out why. The findings of this workshop have made Bennetts secure in the knowledge that it can design buildings to perform at 30kgCO2/m2/yr. In a similar initiative, architectural practice Architype won £15,000 in the Ashden Awards for Sustainable Energy to undertake post-occupancy monitoring of its projects.
More practices should follow suit. The work is time-consuming and painstaking, but essential. Environmental project data, such as target envelope U-values, glazing ratios and airtightness factors, need to be developed. Now that workloads are down, this is an ideal time for architects to take charge of these numbers.
Organisations already exist for specific building types which can provide a natural home for this research: the British Council for Offices, the CIBSE School Design Group and the Construction Industry Research and Information Association’s Learning Network for Sustainable Healthcare Buildings, for example. CarbonBuzz, the joint RIBA/CIBSE online tool for energy-use monitoring (www.bre.co.uk/carbonbuzz), is the ideal repository for gathering and comparing this information as it becomes available.
Is it really too much to ask architects to take as much care with energy data as they do with photographs for a building study?
AJ building studies for which no CO2 emissions data was provided
Rogers Stirk Harbour + Partners
Heathrow Terminal 5
Eden Court Theatre
London Rowing Club
Alan Turing Building
Oak Park Research Facility
David Chipperfield Architects
Empire Riverside Hotel
Tony Fretton Architects
Fuglsang Art Museum
Glenn Howells Architects
National Film and Television School
Stock Woolstencroft and S333
Keith Williams Architects
Wexford Opera House
Elder and Cannon
Clash and Hawkins/Brown
The Level Centre
Pringle Richards Sharratt
Herbert Museum and Art Gallery
Elder and Cannon
Niddrie Mill and St Francis Primary Schools
Robbrecht en Daem
Rick Mather Architects
MacCormac Jamieson Prichard
British Embassy, Bangkok
Teenage Cancer Centre Trust
David Chipperfield Architects
City of Justice, Barcelona