The Building Webinar below was held shortly after the introduction of Part L2013 on the 1st May 2014.
The presentations and discussions on this recording contain useful insight on the changes from the previous version of Part L , thoughts on how to comply with the new regulation and the general direction of travel towards Zero Carbon from respected industry experts and commentators.
The content would form a both a useful introduction to Part L1A 2013 and a kick off point for deeper consideration on the subject.
AMBITION VS REALITY
- Vern Pitt, Senior Reporter, Building
- Tassos Kougionis, Technical Manager, Zero Carbon Hub
- Stephen Wise, Technical Development Manager, Knauf Insulation
- Kirk Archibald, Associate Director, PRP Environmental
- Richard Stockholm, Operations Manager, NHBC
The 2013 versions of Part L1A (conservation of fuel and power in new dwellings), and Part L2A (conservation of fuel and power in new buildings other than dwellings) came into effect on 6th April 2014 (in England only).
The headline change was a reduction in the carbon dioxide emissions from the mix of new buildings (6% for Dwellings and 9% for other buildings), which although not as big an improvement as was expected, it is still to be welcomed.
A more thorough examination of the changes to each section is shown below.
Housebuilders can now start to look at how new homes of the future will need to perform, if they are to meet the regulatory requirements which came come into effect (in England only) on 6th April 2014.
The headline change was a 6% reduction in the carbon dioxide emissions from the mix of new dwellings, which although not as big an improvement as was expected, it is still to be welcomed and the introduction of a Target Fabric Energy Efficiency Standard (TFEE) which accounts for a dwelling’s combined, annual heating and cooling load for which a limit is set based on the performance of notional dwelling of the same size and shape as that being assessed, but with fixed values for the fabric performance (U-values, thermal bridging, air leakage etc) a 15% margin is then added giving the designer some additional design flexibility.
One of the simplest changes is the introduction of an “elemental recipe“ which is detailed within the “notional dwelling specification“. If the “notional dwelling specification“ is adopted in its entirety then this will be sufficient for the dwelling to comply with the fabric energy efficiency and carbon emission requirements of Part L1A.
As with any recipe the blend of ingredients can be amended to suit the needs of the individual which in this instance means that there is great deal of scope when it comes to the specification of elemental fabric U-values, although it will still not be possible to comply by solely adopting limiting U-values.
At first glance, the elemental recipe fabric U-values appear to be quite challenging, however, there is a great deal of variability that can be adopted to achieve compliance.
Extract from ADL1A notional dwelling specification
|Fabric element||U-values (W/m2K||LimitingU-values (W/m2K|
|Windows, rooflights and glazed doors||1.40||2.00|
For instance, with the Knauf Insulation elemental recipe, a typical semi-detached house shows compliance with the fabric energy efficiency requirement by adopting the fabric U-values in the table below*.
Knauf Insulation example elemental recipe
|Fabric element||U-values (W/m2K)|
|Windows, rooflights and glazed doors||Between 1.20 & 1.30|
*Assessed using SAP 2012
The headline change was a 9% reduction in the carbon dioxide emissions from the mix of new buildings, which although not as big an improvement as was expected, it is still to be welcomed and came into effect (in England only) on 6th April 2014.
The limiting U-values for the main fabric of the building remain unchanged as detailed in Table 1 below.
Table 1 - Limiting fabric parameters
|Fabric element||2010 U-values (W/m2K)||2013 U-values (W/m2K)|
|Windows, rooflights and glazed doors||2.20||2.20|
One major change from Part L2A 2010 is that a wider set of “notional buildings“ has been defined, the air permeability and thermal requirements are detailed in Table 2 below.
Table 2 - Notional Building Specification - ADL 2A 2013
|Element||Side lit or unlit (where HVAC specification is heating only)||Side lit or unlit (where HVAC specification includes cooling)||Toplit|
|Air permeability (m3/m2/hour)||Varies between 3 and 7 dependent on the gross internal floor area of the building - where the floor area is less than 250m2 or over 10000m2|
As can be seen from Table 2, compliance with the new Part L2A maintains the emphasis on having a well insulated building fabric which cannot be achieved by adopting the limiting fabric parameters identified in Table 1.
The exact impact of the new Part L2A requirements can only be determined by interrogation using a special version of SBEM called "cSBEM", which was created to accompany the recent consultation on the 2013 revision of Part L of the Building Regulations in England and can be accessed at www.2013ncm.bre.co.uk.
So until then its a case of watch this space for an update and detailed solutions guidance!