Sustainable buildings – work in progress?
Ant Wilson, director, Faber Maunsell reviews the main elements of the drive for more sustainable buildings and how this fits within the UK's wider efforts to tackle the main causes of climate change.
Every passing week seems to see yet more announcements or reports on the detrimental environmental impact of our activities. With both main political parties fighting to promote their environmental credentials to gain the ‘green vote’, the sustainability agenda looks set to continue its rise in prominence.
Dominating the agenda at present is the question of how we tackle the causes of global climate change. Accepted as central to this is the need to reduce emissions of CO2. With almost half the carbon dioxide produced in the United Kingdom derived from producing buildings and the burning of fossil fuels to provide energy for heating, lighting, ventilating and air-conditioning buildings.
Progress with improving the sustainability of our buildings can be seen as a benchmark of our performance on the wider environmental agenda.
Buildings also play such an important role in our lives and provide a very visible symbol of an individual’s, organisation’s or even a country’s sustainable development principles and commitment to reducing carbon dioxide emissions.
The UK’s recent history of striving to create more sustainable buildings stems from the launch of the European Union’s Energy Performance in Buildings Directive at the end of 2002, which sets out a framework to improve the energy performance of buildings within the EU.
In practical terms, there are four main aspects to the Directive which impact on owners, operators and developers of both domestic and non-domestic buildings.
These are covered in Articles three to nine and cover the establishment of a methodology to calculate the energy performance of buildings, the setting of minimum energy performance requirements for both new and large existing buildings, the requirement for the display of an energy performance certificate and the inspection of boilers and air-conditioning systems.
In relation to the methodology, the Directive does not specify a detailed method of calculation, but what it does do is clarify that the overall energy performance of the building must be taken into account – including services such as heating, air-conditioning, ventilation and built in lighting.
For domestic dwellings, a system incorporating most of the Directives requirements has been in place in the UK for some years in the form of the Government’s Standard Assessment Procedure for Energy Rating of Dwellings, known as SAP.
These were extended in 2005 to ensure full compliance with the Directive. For non-domestic buildings, a new methodology has been developed known as the Simplified Building Energy Model (SBEM). Together SAP and SBEM set out the UK Governments methodology for calculating a buildings energy performance. Other detailed simulation computer programs have also been accredited.
The Directive then requires minimum energy performance requirements to be set in relation to the carbon dioxide emissions from the whole building. What the Directive does not do is set out what the performance standards should be or how they should be arrived at, this is left to the discretion of each Member State.
In the UK the specific requirements are set out in Part L of the Building Regulations. These classify standards for new dwellings (L1A), work in existing dwellings (L1B), new non-domestic buildings (L2A) and work in non-domestic buildings (L2B).
The standards determine the maximum carbon dioxide emissions in relation to a notional gas-heated building of the same size and shape as the proposed building that comprises precisely to the 2002 Part L regulations.
To ensure progress is made in making buildings more energy efficient, an improvement factor is then applied above this 2002 level. For domestic buildings the improvement factor is 20% and for non-domestic the overall improvement required is between 23.5% and 28% depending on how the building is ventilated.
Because the building’s efficiency is measured in terms of CO2 emissions, the type of fuel used to heat a building is highly significant as different fuels produce very different CO2 emissions for a given quantity of heat.
Of the fossil fuels, natural gas has the lowest emissions while others will require additional measures to limit the building’s emission to the target level. This is expected to encourage the use of what are known as low and zero carbon (LZC) technologies such as biomass, wind turbines or solar energy, especially for buildings located off the mains gas grid.
The third key element of the Energy Performance in Buildings Directive is that an energy performance certificate is required whenever a building is constructed, sold or rented. This, in effect, provides a test of the building’s energy performance using the SAP or SBEM methodology as detailed earlier.
The UK Government has not yet implemented this part of the Directive and it is likely that this will be phased in between now and January 2009 applying to different sectors in turn. For dwellings the certificate will form part of the Home Information Packs (HIPs) which are due to be introduced soon. For public buildings and those providing a service to the public which are over 1000m2, the certificate will need to be displayed in a prominent place.
The certificate is likely to rate a building on a scale of A (best) to G (worst) in a similar way to the system already used for electrical goods. An important element of the certificates is that they will be accompanied by recommendations for cost-effective improvements such as insulation or improvements to the heating or ventilation system which would help to improve its energy efficiency.
The final element of the Directive which will have a significant impact on improving energy performance is the requirement for the inspection of boilers and air conditioning units. The Directive sets out two options for boilers and sets a 12kW threshold for air conditioning plant. An announcement from the Government on the implementation of these measures is expected soon.
The impact of the Directive in the UK has already been seen in the new Part L Building Regulations, which came into effect in April 2006, and is already having a significant impact in terms of limiting the CO2 emissions from new buildings. The energy performance certificates and inspection of boilers and air conditioning systems can only help to make further significant reductions.
This drive for more sustainable buildings is therefore already having a significant positive effect on the UK’s efforts to meet its overall CO2 commitments under the Kyoto Protocol.
So what’s next? How can we improve further? The launch of the Code for Sustainable Homes in December last year shows the direction of the Government’s thinking on this. A development of the Building Research Establishment’s EcoHomes scheme, the code is a voluntary scheme based on a star rating system illustrating the sustainability of new homes as a complete package.
The Code sets minimum standards for energy and water use enablig developers to demonstrate the sustainability of their new homes and providing consumers with a quality standard.
While the Code only relates to new homes, it is possible to see a time when a similar standard could be developed for non-dwellings. Whatever the next steps, there appears to be agreement that improving the energy efficiency and overall sustainability of our buildings is key to meeting the challenge of reducing our CO2 emissions.
Nemex is one of the events taking place at Sustainabilitylive! from 1-3 May 2007 at the NEC in Birmingham. For the latest news on exhibitors, the features programme and to register for free attendance, please visit: www.sustainabilitylive.com or call +44 (0) 870 443 6089.