New Building Regulations for 2010

The first of October is the date the 2010 changes to Parts F, J and L of the England & Wales Building Regulations take effect. However, there will be a transitional period - any projects already under way can continue to follow the old regulations right through to completion.

Part L for New Buildings

Approved Document L2A, Conservation of fuel and power in new buildings other than dwellings was first published in 2006, and was quite a radical departure from its predecessor. The 2010 Approved Document L2A sticks with the same 5 criteria for compliance, with fairly minor changes to each. The biggest change is that the Target CO2 Emissions Rate (TER) fall by 25%. The 2010 TER will be the emissions from a newly-defined notional building, and the specifications for this building have been set such that buildings on aggregate will achieve 25% lower emissions than under the 2006 Part L.

As well as building designs meeting overall CO2 emissions targets, individual elements of the design have to meet minimum standards, sometimes known as "backstops". In order to meet the TER, designers would typically have to select elements that are considerably better than these standards. Some of them, for example U-values for walls, roofs and windows, are unchanged from the 2006 to the 2010 documents. Others have been beefed up, for example minimum efficiencies of boilers, chillers, air distribution systems and lighting.

Under the 2006 Approved Document L2A, designers of buildings without cooling had to prove that the building would not overheat in summer, whereas no such calculations had to be carried out for cooled buildings. In the 2010 document, a new method has been established to deal with the problem of solar gains in all buildings - the design is compared against a reference building with a fixed amount of glazing. Designers would have to do calculations showing that solar gains are less than the reference building. This signals a clear move away from "glass-box architecture" and towards dealing with solar gains through passive means.

The requirement for commissioning has been present since the 2006 changes to the Building Regulations. Additional guidance has been added to the 2010 document regarding production of a commissioning plan, with a reference to BSRIA BG 8/2009 Model Commissioning Plan.

Part L for Existing Buildings

Various types of work on existing buildings fall under Part L of the Building Regulations, including extensions, material changes of use, replacement windows, and new, replacement or extended building services. All this is covered in Approved Document L2B, Conservation of fuel and power in existing buildings other than dwellings.

Unlike for new buildings, there is no need to carry out whole-building CO2 emissions calculations or airtightness testing. Individual elements of the work carried out will need to comply with minimum standards. As these are the only mechanism by which work in existing buildings can be made more energy efficient, most of these standards have been enhanced. Examples of new U-values are given in the table below. Note that there are no longer separate U-values for new elements (for example in extensions) and replacement elements, and also that maximum U-values have been introduced for swimming pool basins for the first time.

Some of the standards for building services in existing buildings are the same as for new buildings, for example those in the table below. Others are lower, for example boiler efficiency, as it is not always possible to replace a conventional boiler with a condensing boiler.

In most cases, it is only the building work carried out that has to meet minimum standards, but in some cases building work may trigger a requirement to carry out further work, known as a consequential improvement. The range of work which could trigger consequential improvement has expanded to include any increase in habitable floor area, for example inserting mezzanine floors or expanding into previously unoccupied areas. Consequential improvements could consist of various types of energy efficiency upgrades to the existing building, ranging from plant replacements to incorporating renewable energy sources, but they only have to be done to the extent that they are feasible. The critical criterion for feasibility is a 15-year simple payback.

Part F - Ventilation

Whereas Part L exists to promote energy efficiency, Part F exists to ensure there is adequate ventilation for people in buildings. Changes include legal requirements for inspection & commissioning of ventilation systems and also provision of operation & maintenance information to users / occupiers. In the case of dwellings, there are now higher ventilation requirements for dwellings with low levels of air leakage.

Part J - Combustion Appliance and Fuel Storage Systems

This health & safety led document has been updated for the first time since 2002. Changes include guidance on concealed flues, Carbon Monoxide alarms for solid fuel appliances in dwellings. Where open-flued appliances are installed, there are now higher requirements for permanently open ventilation openings in buildings with low levels of air leakage. Further details on the changes to Part J are available from BSRIA.

New Building Regulations, Approved Documents and key second-tier documents can be downloaded from the Planning Portal website.

BSRIA seminar presentations

BSRIA hosted a half day seminar on 28 September 2010 on behalf of CLG to summarise the changes to the new Building Regulations. Presentations are available to download for free below: