Part L of the Building Regulations

Part L is the section of the Building Regulations dealing with conservation of heat and power from new and existing domestic and commercial buildings. It is being updated because the UK Government has a legal commitment to implement the European Directive on Energy Performance in Buildings (EPBD), which requires all new and existing buildings to be given an energy rating, and for new buildings to meet a minimum standard of energy efficiency.

A major reason for this emphasis on energy efficiency (apart from the essential need to save fossil fuels as far as possible) is because of global warming, mainly caused by burning fossil fuels. This phenomenon is caused by so-called 'greenhouse gas' emissions into the atmosphere. Such gases may be natural (such as methane) but are also largely man-made (such as carbon dioxide - CO2), and their emission into the Earth's atmosphere is causing it to heat up.

As stated in the earlier (October 2005) VoltiBULLETIN on Part L, the costs to the world will be huge, and purely in financial terms, one estimate has it that, if no action is taken, climate change will cost society, up to the year 2200, €74 trillion in current prices. This is especially important bearing in mind that the fact that around 40% of all UK CO2 emissions derive from buildings, and is the background to the latest revisions to Part L of the Building Regulations is intended to help by making buildings more energy efficient.

Revisions to Part L:

There are a number of sections to Part L. Part L1A deals with the requirements for new dwellings. For new dwellings, the current compliance methods are to be abolished, to be replaced by a new 'whole building' methodology based on carbon emissions. To demonstrate compliance, designers must demonstrate that the predicted actual carbon emissions from the building, known as the Dwelling carbon dioxide Emission Rate (DER), are less than or equal to a calculated target (Target carbon dioxide Emission Rate). Improvements to the building fabric (for example) or heating system efficiency improve the DER, allowing compliance to be achieved. For new buildings, minimum air tightness standards will also apply.

New SAP version:

Because of the above, a new version of SAP (SAP2005) is being produced to enable the calculations to be carried out. SAP is the Standard Assessment Procedure for producing an energy rating for a dwelling, based on the calculated annual energy cost for space and water heating. SAP considers energy efficiency, and is concerned with the size of the building, its insulation levels, ventilation system and its heating and hot water systems. SAP rating can then submitted for Building Regulations approval and is checked by the local Building Control department. Currently, the SAP is normalised for the floor area and the higher the rating number, the lower the carbon emitted. Therefore, SAP is similar to the fuel consumption of a car under standard driving conditions. All new buildings must have a SAP rating.

The new Part L (ADL1A), on the other hand, makes SAP a carbon compliance tool, and the regulation is concerned with carbon as a policy driver rather than the cost implications of fuels used within SAP. Moreover, SAP does not take into account the greater capital cost of equipment, regular servicing and on-going maintenance requirements related to gas and oil systems.*

The revisions currently being made to SAP will align it to Part L 2006 and are expected to include (among other things), energy for lighting, a revision of solar water heating, the incorporation of additional renewable and energy saving technologies, and more besides.

It is also thought likely that a (reduced) version of SAP will be used within the implementation of the European Performance of Buildings Directive and therefore in producing the energy audit required with a Home Information Pack from 2007.

So, there are many implications for specifiers and contractors involved in new building work, and - in the rest of this VoltiBULLETIN - readers are able to learn about Part L and SAPs in greater detail.

*Information from Applied Energy Products.