The guidance document can be downloaded here.

New regulations: AD-L2 2013 England; L2 2014 Wales and Section 6 2010/2015 Scotland

The latest amendment to the England AD-L2 and Wales L2 Regulations for the conservation of fuel and power (2013) came into effect on 6 April and 31 July 2014 respectively. This is the third amendment following the introduction of these mandatory regulations in 2002. The revision to Section 6 Scotland is scheduled for October 2015.

The 2013/4 Amendments are the latest stage in the Government’s planned progress to nearly net zero energy buildings by 2019. The emphasis is based on setting challenging on-site targets based on what levels of improvement would be cost-effective over the next few years. AD-L2 [England] and L2 [Wales] follow the principle of the 2010 Regulations but with significant changes in the definition of the types of buildings that make up the aggregate mix. As before, the whole building is assessed using the SBEM ‘whole building methodology’ that expresses the energy performance.

In addition the Welsh regulations have introduced an additional requirement that assesses Primary Energy Consumption.

Major Changes since 2010

    • England: 2013 introduces further changes in the way non-domestic buildings are assessed. New Notional Building targets have been set for a variety of non-domestic building types and are based on an average further improvement of 9% over 2010 levels.
    • Wales: The improvement over 2010 levels is an average of 20% over the designated non-domestic building types
    • Wales: Measures have been included to safeguard the projected energy savings by including additional criteria for compliance covering ‘Primary Energy Consumption
    • Scotland: The present requirements remain in place until October 2015 when considerably stricter requirement come into force. These will include an improvement 43% over 2010 levels

Implications of the target improvements

In order to achieve the significant improvement in energy/carbon emissions savings, the set values in the Notional Building have been substantially improved compared to 2010, including:-

  • Lower fabric U-values
  • Lower air permeability rate
  • Improvements to lighting and controls
  • Improved efficiency of services and controls
  • Limitations on the effect of solar gain

The level of improvement is so significant that in order to comply, all aspects of the building will have to be improved or made more efficient. In the case of Wales and Scotland it is also assumed that there will be contribution from renewable energy sources e.g. photovoltaics or equivalent, whereas it is still feasible to achieve compliance with ADL2A 2013 England through building envelope performance without renewables at this stage.

U-Value Requirements

The new U-value requirements for AD-L2A England and Wales include backstop values of 0.25 W/m2.K for Roofs and 0.35 W/m2.K for walls. The 2013 Notional building values are set at 0.18 W/m2.K and 0.26 W/m2.K for walls. The values for Scotland are currently still at 2010 levels and will be revised in 2015.

ForAD-L2A England and L2A Wales the Notional Building values are set at 0.18 W/m2.K for roofs and 0.26 W/m2.K for walls. The values for Scotland are currently still at 2010 levels of 0.16 W/m2.K for roofs and 0.25 W/m2.K for walls and will be revised in October 2015

EPIC recommends designing to at least the Notional building U-values or better as a straightforward route to compliance.

New airtightness levels

In ADL2A:2013 air permeability is the only part of the fabric performance that has been improved beyond 2010 levels. The major change is that air permeability levels are defined according to ‘Gross Internal Area’ (GIA), becoming lower as GIA increases. Requirements now vary between 3 and 7m3/m2/h.

However, research has shown that the smaller the footprint of the building, the harder it is to achieve lower air permeability. Following this research and representations from EPIC & MRCMA, the levels for smaller top-lit buildings (below 250m2) have been relaxed to 7m3/m2/h. There is a backstop value of 10m3/m2/h.

Full details of the changes and guidance on compliance using insulated panel systems can be found in the latest EPIC guide, available to download here.