This article reviews the recent and forthcoming updates to Building Regulations across England, Wales and Northern Ireland.
There is a common thread that runs through the updates for 2014 across the three nations: changes made are required by the Energy Performance of Buildings Directive (EPBD). The EPBD is designed to increase energy efficiency of buildings.
Other requirements of the EPBD include:
- Requirement for renovation of existing buildings
- Definitions of 'major renovation' in existing buildings
- Requirements for nearly zero-energy buildings
- Requiring the feasibility of high-efficiency energy alternatives to be considered
- Cost optimality for buildings
- Historic buildings
- Energy performance certificates (EPCs).
The national strategy for zero carbon buildings through the Climate Change Act requires the UK to reduce its greenhouse gas emissions by 80% below base year (1990 and 1995) levels by 2050. The UK Government has stated through its Carbon Plan that by 2016 new dwellings are to be zero carbon, with all new non-domestic buildings zero carbon by 2019.
The devolved administrations of Wales, Scotland and Northern Ireland are working within their own circumstances to deliver the targets set by the Act.
The following is an update of the changes made to Building Regulations in progression towards the above reductions.
In addition to the above common changes, the main 2013 changes in England to Approved Document L are:
- The appearance of the new documents is single column format in plain English
- New Regulation 26A requires fabric energy efficiency rates for new dwellings, in addition to pre-existing carbon dioxide targets. Other Regulations amended to accommodate this. The primary intent for this is to prevent sub-standard fabric with excessive trade-offs using dubious renewable sources
- The specification for the notional dwelling has been reinforced to deliver a reduction by 6% of carbon dioxide emissions. For non-domestic, the notional building is split into side-lit or unlit and top-lit options. The target is a saving of 9% over Part L 2010, averaged across the range of building types.
These changes take effect on 6th April 2014.
New housing and Approved Document L1A (England)
The Target CO2 Emission Rate (TER) in the 2010 Approved Document was calculated using a 2002 notional dwelling, constructed to a set of reference values reporting emissions from heating, hot water and lighting and adjusted using emissions and fuel factors. The 2013 changes are:
- The TER is based on emissions from a notional dwelling with concurrent fabric and services standards (model designs). The TER is based on a gas fired boiler and other factors such as a defined level of thermal mass. It is altered by a fuel factor that allows for use of fuels that produce more CO2
- In addition to the TER, there is the introduction of DFEE and TFEE (dwelling and target fabric energy efficiency). Once calculated, the TFEE is altered by a factor of 15%; if you build to the elemental recipe you will pass by 15%. This gives flexibility to worsen the fabric specification but may fail the TER, you will then need to improve other aspects or consider alternatives as below
- Making buildings ready for future Low or Zero Carbon technology (LZC)
- Limiting fabric parameters same as 2010
- Consideration required, via assessment of feasibility, of high efficiency alternative systems (Article 4 of the recast EPBD) such as renewables, cogeneration, district heating and heat pumps.
Based on the above 2013 requirements, the Kingspan website 'insulation – blog ' shows that for a semi-detached house built in masonry, using their insulation products and 'Constructive details', a DFEE of 47.60 (assumed measure of kWh/m²/year) is attained. To achieve a U-value of 0.18W/m²K, a wall thickness of around 350mm is offered. Obviously, use of mineral wools may increase the overall wall thickness slightly. In general terms, compliance can be achieved not with renewables but with high fabric performance, heat recovery on services and weather compensator.
The target for the 2016 zero carbon home (set by Zero Carbon Hub) recommends two levels of FEE (max) at 39kWh/m²/year for a mid-terrace house and 46kWh/m²/year for an end-terrace, semi or detached house. See, for example, DCLG document Next steps to zero carbon homes – Allowable solutions .
As we appear to be approaching these targets, and endeavor to approach zero carbon, the Next steps document is suggesting that it may not be economically viable to achieve zero carbon targets through (even greater) on-site measures alone. The example of Passivhaus is cited. The 'Allowable Solutions' approach would give developers a variety of compliance routes and flexibility options for carbon abatement. This could involve, as part of say a new build development, retrofit of existing buildings, carbon abatement funds or on-site through connected measures; other options are being debated. The Government does not think such measures be confined to the domestic sector.
Manufacturers are stating (from early trials) that thermal bridging details are now becoming more important due to the increased levels of performance required. The Concrete Centre has published a useful guide, Thermal performance: Part L1A , which covers 2010 to 2016, along with thermal properties of generic walls and floors against thermal mass and insulation performances.
New buildings and Approved Document L2A (England)
The 2013 changes are:
- The properties for the notional building have been 'strengthened' to give an aggregate 9% reduction in carbon dioxide emissions against 2010 standards. The reductions vary across building types, with small warehouses requiring a 3% reduction, while shallow plan offices require a 13% reduction
- A wider set of notional buildings are defined for top-lit, side-lit. Notional building air permeability has also been sub-divided by size. Air permeability levels range between 3-7m³/m²/hour, dependent upon gross internal floor area
- Multiplying factors for modular and portable buildings are revised to follow 9% aggregate improvement in CO2 emissions
- Consolidation of 2012 amendments; requirement for consideration of feasibility of high-efficiency alternative systems
- New output criteria for gas and LPG boilers added to the new non-domestic building services compliance guide. Boilers ≤2MW to have efficiencies of 91% and 93% respectively. For replacement boilers there is a slight increase
- Minimum efficacy for general lighting is now 60 luminaire lumens/circuit-watt. The lighting energy numerical indicator (LENI) can now be used as a methodology for calculation of efficiency
- An improvement in the Building CO2 Emission Rate (BER) is recognised in the National Calculation Methodology where low-pressure ductwork has been tested to the requirements set.
Existing buildings and Approved Documents L1B and L2B (England)
The original document format remains with changes made piecemeal. There have been minor changes to the standards for controlled fittings, which now include:
- The Door Set Energy Rating (DSER) standard for doors is now used in Approved Documents L1B and L2B
- Additional guidance on evaluating U-values for out-of-plane rooflights is provided.
The requirement for consequential improvements has not been included as part of the updates.
As with England, changes in Wales have been made to take account for the EU Energy Performance of Buildings Directive (EPBD); the four documents are in a new format and will apply in Wales only. Drafts are available on the Wales government website and include:
- For domestic 'mix' an 8% improvement and non-domestic a 20% aggregate improvement on 2010
- Analysis required of high efficiency energy alternatives for new buildings
- Definition changes in relation to EPCs and Schedule 1 of what constitutes a 'major renovation' of existing buildings and requirement for any subsequent upgrading
- Changes take effect 31 July 2014
- Introduction of a 'design-construct-operate' flow chart.
Note that excepted energy buildings, e.g. generating stations, electric lines and pipe-lines as defined in the Schedule to Welsh Ministers (Transfer of Functions), are still covered by the England Part L.
New housing and Approved Document L1A (Wales)
The 2013 changes are as follows:
- Similar compliant elemental recipe as England for calculation of the TER, based on a gas central heated dwelling. The reference dwelling opening area, for windows and doors, is set at 25% of the total floor area of the actual dwelling
- The fabric recipe additionally includes: windows and glazed doors based on a whole window U-value, more stringent thermal bridging targets, a set thermal mass parameter
- The England Fee targets have not been adopted. Instead, the Wales are using tighter area weighted limiting backstops
- The insulation of circulation pipes within dwellings and communal spaces in blocks of flats has been given emphasis.
New buildings and Approved Document L2A (Wales)
The 2013 changes are as follows:
- Compliant recipe retained and tightened in some areas
- Introduction of elemental options for notional building specification of side or top-lit glazing (as England)
- TER/BER comparison retained but with introduction of the Primary Energy Consumption (PEC) test, under the new Regulation 26A. This is applied before application of renewables. Introduced to avoid 'green wash' – the introduction of inappropriate measures to compensate for lower performing fabric and services
- The TPEC and BPEC are a measure of the energy efficiency of the building fabric and services. To achieve this measure, the fabric will need to be properly considered along with carbon targets.
Existing buildings in Wales
The headings in the documents have been rationalised so we now have extensions, conversions and renovations. Each of these categories carries U-values for specific works to thermal elements. Both dwellings and non-dwellings will require consequential improvements to extensions and conversions.
Existing Buildings and Approved Documents L1B (Wales)
The 2013 changes are as follows:
- For new thermal elements ('extensions' to domestic fabric), the requirements have been tightened. These values align with the backstops for domestic new build (Wales L1A)
- For 'conversions' (of garages/lofts), previous elemental standards remain. 2010 values are retained, but with slightly different terminology and meaning ('threshold' replaced with 'limiting')
- For 'renovations' (existing in-use domestic fabric), U-values and guidance is the same as for 'conversions'
- Extensions and conversions to dwellings trigger consequential improvements, depending on whether they are greater or less than 10m². Improvements include full filling of cavities, loft insulation to 250mm and upgrades to hot water cylinder insulation
- Requirement for controlled fittings (windows and doors) expanded and values revised slightly
- A conservatory, where exemption is lost if criteria not met, would become an 'extension' or a 'conversion' dependent on whether it is existing or new. Then subject to elemental criteria.
The greater design flexibility approach to compliance has been extended to include conversions, conservatories, change of use (to dwelling) and renovations.
Existing Buildings and Approved Documents L2B (Wales)
The 2013 changes are as follows:
- For new thermal elements, a new category has been added to include buildings essentially domestic in character, e.g. care homes, student halls, etc. Extensions to these attract tighter standards than the other non-domestic buildings, but generally standards are tighter than 2010
- Conversions and renovation have similar U-value requirements equivalent to 2010, but with different terminology and meaning ('threshold' replaced with 'limiting')
- The optional approaches for design flexibility ('U-value trade-off' and 'carbon target'), similar to domestic, can now also be used for alterations, conversions and renovations
- Consequential improvements are now applied to buildings of all sizes where being extended, or with new or extended capacity of services.
Main changes to Building Regulations
Consultation on changes came out in December 2013. Following this, an amendment document went live (available online at www.dfpni.gov.uk) on 24 February 2014 for use on 25 February 2014. The following changes, primarily in relation to the EPBD, were identified:
- Consideration of high efficiency alternatives
- Definition, as Wales, of what constitutes 'renovation', including 'major renovation'
- Clarification of policy on protected buildings
- Clarification on exempted buildings.
Technical Booklets F1 and F2
Both documents are revised to broadly cover considerations, definitions and clarifications listed above. There are no additional carbon emission reductions over the 2012 documents.