Part L: what you need to know

What is it?

Part L of the building regulations deals with the conservation of energy in residential properties, offices and other buildings. It sets high standards for architects, engineers and contractors to create a more sustainable built environment.

When did it come into force?

It came into effect on 6 April this year but only applies to projects started after 1 October 2006. It has not been an easy introduction. There have been complications in the delivery of the software needed to calculate compliance and little time for those who will administrate it to get up to speed with its complexities.

Why introduce new regulations?

The government is committed to reducing global warming by cutting greenhouse gas emissions and has set a target of reducing 1990 emissions of carbon dioxide by 20% by 2010. Operational energy – burning fossil fuels for heat, light and cooling in buildings – accounts for almost half of the UK’s total energy consumption. Through the use of modern materials, construction methods and technology, significant reductions in energy use and carbon dioxide emissions should be achievable.

What has been the effect?

Part L has had a major impact on the construction industry, affecting all professionals involved in the design and construction of new and existing buildings.

Some of the key changes that designers and contractors have had to get to grips with are controlling solar gains, the new requirements for energy performance rating and air tightness compliance, plus there is the calculating, commissioning and reporting that goes with this.

The QS must ensure the
finished building meets CO2 emission targets

Where do QSs come in?

The challenge for the QS is to ensure construction follows a design that means the finished building meets CO2 emission targets. The regulation requires a whole-building calculation methodology to work out carbon emissions.

This is to be done using the approved software. The designer enters data on the materials used and the programme determines whether the building complies.

Remember that as a building’s energy performance is calculated as a whole, any changes to its compliant design once under construction can have an adverse effect upon its performance. For example, adding more insulation to improve a building’s energy performance may cause overheating in the summer, leading to more electricity being used for air conditioning. Using inferior materials to cut costs, such as cheaper insulation, will lead to an increase in winter heating and a reduction in energy performance.

A building’s energy performance must be checked at concept to ensure it meets the regulation and then monitored through design and construction to make sure it complies in practice. The QS must guide the client to make key decisions on materials, fittings and appliances at the design stage. The QS must also ensure the architect designs a building that can be constructed and that the contractor employs staff that can build it to the specification demanded using the materials required within budget. Should the building fail on completion, the consequences could be expensive.

What’s next?

Further revisions to Part L are expected in 2010 after articles 7 to 10 of the European Energy Performance of Buildings Directive are implemented. They cover energy performance certificates and energy labelling, are implemented by 2009.

Who do I contact for more information?

An approved building inspector, such as pt Building Standards, can provide consultancy at all stages of the build programme. Information is also available from the Department for Communities and Local Government (www.comm-unities.gov.uk). Stuart Holt is managing director at pt Building Standards, which advises commercial and industrial projects on the legal requirements of building regulations