October 2010 part L and Part G Compliance
In October 2010 the Government updated the building regulations from 2006, calling for a 25 percent reduction in carbon emissions.
2013 standards will cut carbon emissions by 40% and by 2016 the Government wants a zero carbon economy.
The standard is set in reference to space, water and lighting. Low and zero carbon technologies will be offered.
The 10 main changes are:
- 25% less Co2 emissions than in 2006, which is 40% less than 2002, complying with the Code for Sustainable Homes level 3, for zero carbon emission in the government’s strategy for 2016.
The Target Emissions Rate (TER) is similar to 2006 with two differences:
- an improvement factor of 0.4 is used rather than 0.2 to give the 40% improvement referred to above
- the SAP 2009 methodology is used to estimate the carbon emissions from heating, hot water, lighting, pumps and fans.
- Cavity party walls- insulating/ sealing them does not count towards the 25%
- Thermal bridges – 0.08 for ACDs no longer an option
- Air permeability – more pressure testing and a confidence factor for untested dwellings
- Low energy lighting – 100% counts towards meeting the TER
- Electric secondary heating – no longer assumed
- New Limiting U values – including for party walls
- Design Submissions now part of regulation- alongside as built submissions
- Addressing the performance gap
KEY CHANGES TO BUILDING REGULATIONS
Part L1A of the Building Regulations comes into force in October 2010. This article from Dyfrig Hughes, Technical Manager for National Energy Services, summarises the ten key changes and presents ways of exploring these changes in more depth.
When you've read this article, you might be interested in reading about the 10 ways SAP 2009 will affect you. You can also see more about our package of online CPD to dig even deeper into the subject.
1. 25% less Co2 emissions than in 2006, which is 40% less than 2002. This is in line with the Code for Sustainable Homes level 3, for the government’s strategy in 2016.
Part L1A 2010 aims to reduce CO2 emissions by 25% over Part L1A 2006. This is a 40% improvement over a dwelling built to the 2002 regulations. This corresponds roughly with the trigger point for Code for Sustainable Homes Level 3, in line with the government’s strategy for getting newbuild dwellings to zero carbon by 2016.
2 The Target Emissions Rate (TER) is similar to 2006 with two differences:
(a) an improvement factor of 0.4 is used rather than 0.2 to give the 40% improvement referred to above
(b) the SAP 2009 methodology is used to estimate the carbon emissions from heating, hot water, lighting, pumps and fans.
The Target Emission Rate (TER) is calculated in much the same way as it was in Part L1A 2006. The main differences are that (The fuel factors have not changed so that electric heat pumps and biomass will continue to be encouraged by the TER; although this is countered to an extent by lower limiting U values (see key point 8). The fuel factor for heat pumps is also to be reviewed after the renewable heat incentive is introduced. The ‘Aggregate’ TER was rejected on the grounds that the benefits did not justify a change in methodology at this stage, despite the Aggregate option being selected for non domestic dwellings. The issue will be re-examined for Part L1A 2013.
3 Cavity party walls- insulating/ sealing them does not count towards the 25%
A key feature of SAP 2009 is that party walls with unfilled and unsealed cavities are assumed to have a U value of 0.5 W/m2K. The notional dwelling used in calculating the TER assumes a U value for cavity party walls of 0.0 W/m2K. This compares to 0.4 W/m2K in last year’s Part L1A 2010 consultation. This means that insulating/sealing cavity party walls will not count towards the 25% improvement target.
4 Thermal bridges – 0.08 for ACDs no longer an option
In Part L1A 2006, it is acceptable to assume a y value of 0.08 W/m2K if Accredited Construction Details have been used. This will not be possible with Part L1A 2010. Instead, the length of each junction will need to be measured, multiplied by the appropriate psi values and added up to produce an ‘effective’ y value.
The psi values can either be values already supplied in the SAP 2009 document or supplied by the relevant approved government ACD scheme. The psi values can also be calculated for specific junctions. A confidence factor will be applied to the psi value calculation for an individual junction if either (a) the calculated psi values are not from a government approved Accredited Details scheme or (b) if no on site checks can be demonstrated to have been made. The confidence factor applied to the psi value calculation is 25% or 0.02, whichever is the larger.
5 Air permeability – more pressure testing and a confidence factor for untested dwellings
The volume of pressure testing required will roughly double. A pressure test should be carried out on three units of each dwelling type or 50% of the instances of the dwelling type, whichever is the smaller.
In addition, a confidence factor will apply to dwellings not pressure tested. Where a dwelling has been pressure tested, the measured value is used in the calculation of the DER. Where the dwelling has not been pressure tested, the value used in the DER calculation is the average of the measured values for dwellings of the same type but with the addition of a confidence factor of 2.0 m3/(h.m2) at 50 pa. This means in effect that the design air permeability must be at most 8.0 in order to meet the maximum allowable value of 10.0 at completion of the dwelling. A value of 15.0 can still be used in small developments.
6 Low energy lighting – 100% counts towards meeting the TER
A minimum of 75% of light fittings must be low energy. If further low energy light fittings are also low energy, the full 100% will contribute towards meeting the TER target.
7 Electric secondary heating – no longer assumed
In Part L 2006, a penalty was applied in dwellings not fitted with a secondary heating appliance. In such cases it was assumed that 10% of the heat in the property came from direct acting electric heaters, thereby significantly increasing the DER. In Part L 2010, there is no such penalty unless the dwelling has a chimney or flue and no appliance is installed; in such cases the calculation is the same as in 2006.
8 New Limiting U values – including for party walls
9 Design Submissions now part of regulation- alongside as built submissions
In Part L1A 2006, it was recommended that a submission be provided to Building Control prior to the building work being completed on site; but this not an absolute requirement.
However, in Part L1A 2010 the person carrying out the work must provide building control the TER, DER and a list of specifications before work starts on site. Then, no later than 5 days after the work has been completed, they must notify Building Control of the TER and DER actually achieved, and whether the building has been constructed as per the design specification; if not, a list of changes to the design specification must be supplied. This is to better enable Building Control to confirm that what has been built aligns with the claimed performance. New outputs from SAP software will be available to help Building Control with this process.
10 Addressing the performance gap
There is growing evidence that completed dwellings do not in practice achieve the intended energy performance. This is referred to by government as the ‘performance gap’. If we are to achieve true zero carbon by 2016 it is vital that this gap be closed. Part L1A 2010 contains various things that aim to contribute to this.
Firstly, the document is clearer than previous versions in distinguishing between ‘Regulation’ and ‘Guidance’ and is less ambiguous in many places. This should help developers better understand what is required of them and give Building Control clearer guidance on how to check for compliance.
Secondly, the requirement to produce a Design submission as well as an As Built Submission, including a comparison of specifications, will hopefully bring more standardisation and rigour to the compliance checks.
Thirdly, the notion of ‘confidence factors’ should start to reward those developers who adopt good quality control procedures both in design and on site. We can expect to see more of these confidence factors in 2013 and beyond.
Changes in Part L (Conservation of fuel and power) building regulations from 2006 to 2010
L1A (new dwellings)
Changes in Legal requirements:
- The exemption from the energy efficiency provisions for extensions consisting of a conservatory or porch is amended to grant the exemption only where the existing walls, windows or doors are retained, or replaced if removed, and where the heating system of the building is not extended into the conservatory or porch.
- A new requirement is introduced, where regulation 26 applies, for CO2 emission rate calculations to be carried out and given to the Building Control Body; along with a list of specifications used in the calculations before the start of building work on the erection of a new building. This is in addition to the CO2 emission rate calculation required to be submitted after completion of the work.
Changes in technical requirements:
- The annual CO2 emission rate of the completed dwelling is now calculated using SAP2009 and must not exceed the target set by reference to a notional dwelling with an additional overall improvement of 25% relative to 2006 standards.
- The notional dwelling now includes a party wall heat loss of zero, meaning that the targeted improvement of 25% is in addition of treating party walls between connected dwellings against heat loss.
- Secondary heating is counted as part of the annual CO2 emission rate of the completed dwelling only when actual provided for any credit is allowed wherever low energy lighting is installed.
- Some of the reasonable limits for building fabric and services performance specifications are strengthened.
- Revised guidance is provided for avoiding thermal bridging at construction joints including the option of adopting a quality assured accredited construction details scheme approach.
- New provisions and guidance are introduced to limit heat loss from a swimming pool basin where there is constructed as part of a new dwelling.
- Appendix A contains guidance for presenting the evidence that demonstrates compliance with the energy efficiency requirements and highlighting key features that are critical in achieving the annual CO2 emission rate target.
L1B (existing dwellings)
- The exemption from the energy efficiency provisions for extensions consisting of a conservatory or porch is amended to grant the exemption only where any existing walls, windows or doors are retained or replaced if the building is not extended into the conservatory or porch.
- The list of work in Schedule 4 (word that need nor be notified to building control) is amended to include the installation of the thermal insulation in a roof space or loft space where this is the only work carried out and the work is not carried out to comply with any requirement in the Building Regulations.
- In this approved document the guidance is generally based upon an elemental approach to demonstrating compliance, with additional guidance that provides greater flexibility. The main technical changes comprise a general strengthening of energy efficient standards that are considered reasonable for work on thermal elements, controlled fittings and controlled serviced in existing dwellings.
- Amended guidance is given where an extension is a conservatory or porch that is not exempt from the energy efficiency requirements or where special considerations apply.
- Amended guidance is given where an extension is conservatory or porch that is not exempt from the energy efficiency requirements,
- The guidance for the renovation of a thermal element through the provision of a new layer or through the replacement of an existing layer has been expanded.
- Guidance is provided for swimming pool basins (walls and floor) in existing dwellings.
Means of ventilation:
New requirements and guidance will be introduced for the installation and commissioning of fixed mechanical ventilation systems. For example:
- Ventilation requirements will be increased in certain situations to take account of increasingly airtight homes.
- Building owners will need to be provided with sufficient information to operate a building’s ventilation system adequately.
Builders will be required to notify the relevant local authority building control body (BCB):
- when a mechanical ventilation system is commissioned; and
- of the measured air flow rate of a mechanical ventilation system in a new dwelling.
Combustion appliances and fuel storage systems
The changes are designed to ensure that combustion appliances function safely in today’s more airtight homes. They will:
- Introduce new requirements aimed at reducing the threat of carbon monoxide poisoning (for example, by installing carbon monoxide alarms in dwellings with new solid-fuel appliances).
- Provide guidance on improving ventilation in “very airtight houses”, especially those where energy efficiency improvements mean that previous escape routes for carbon monoxide (such as draughty windows in old houses) have been eliminated.
Conservation of fuel and power
New requirements will be introduced with the aim of improving the energy efficiency of new homes by 25%. The amendments will:
- Adjust how the target emission rate (TER) is calculated.
- Introduce a requirement to provide the BCB with a TER and dwelling emission rate (DER) before work starts. After completion, the builder will need to notify the BCB of the TER and DER actually achieved. Also, if the work was not carried out to specification, then the builder will have to confirm how the specification changed.
- Add margins of error to calculations where actual energy efficiency figures are estimated or extrapolated from existing data. In effect, this will encourage a detailed energy assessment of every building.
Part L (Conservation of fuel and power)
2.43 Eighty-two responses directly referred to Part L. It should be noted that Part L was recently reviewed which resulted in a suite of new guidance documents being issued in April 2010 with provisions only coming into force on 1 October. Many peoples’ experience will have been with the previous guidance suggesting that some of the issues raised may have already been addressed.
2.44 That notwithstanding, the biggest concern related to the complexity of guidance, some of which was considered to be beyond the understanding of many. It was widely suggested that a key consequence of this complexity was that compliance suffered as people failed to understand what was required of 11 them. Tied up in this was criticism of the complexity of the software used to calculate energy performance which it was suggested meant many required additional input from third party specialist providers.
2.45 A number of solutions were suggested including a return to showing compliance using the “deemed to satisfy” method; the adoption of the German “Passivhaus” standards; and making the process less complicated by the use of checklists to verify compliance.
2.46 The Department acknowledges that, driven by requirements to introduce overall energy performance targets for buildings, the guidance and calculation tools have over time become more complex. It will be mindful of the call to minimise complexity as it takes forward its programme of work into 2011 and beyond. These concerns will also be fed through to the review of the software for calculating energy performance which will be carried out in tandem.
2.47 The Department is also encouraging the production of simpler guidance, additional to the Approved Documents aimed at making the main requirements of Part L understandable to a broader audience. An example of this is the Loft Conversion Guide produced by the Construction Products Association which came out in September 2010.
2.48 Other more specific points included concern about the frequency of the changes to Part L, calls for the introduction of “consequential improvements” under Part L as a way of contributing to improvement of the existing stock, and suggestions that lighting efficiency could have a bigger role to play than is currently the case.
2.49 The Department will remain mindful of the points raised as we carry out the next Part L review – the aim of which will be to make and ensure implementation of further cost-effective changes to the energy efficiency of buildings. This will be undertaken in the context of wider policies to improve the energy performance of new and existing buildings. It will include taking the next step towards zero carbon buildings being mindful of the work of the Zero
Carbon Hub and including support for the wider retrofit policy and the introduction of the Green Deal. In securing such improvements we will seek to ensure that no adverse consequences are created as part of this, for example, from better insulated and air-tight buildings increasing the risks of overheating and reduced indoor air quality.
Part G (Sanitation, hot water safety and water efficiency)
2.29 There were 19 responses that mentioned Part G. The Your Freedom website also contained Part G-related discussion threads. Most comments focused on two of the recent additions to the provisions – the introduction of a minimum water efficiency standard for new homes and the introduction of a requirement to prevent scalding by limiting the temperature of bath water in new homes, often achieved by fitting thermostatic mixing valves.
2.30 In relation to thermostatic mixing values, there was little submitted directly to the Department. However, there was some debate on the Your Freedom website about whether regulations should govern the temperature of people’s bathwater and whether this control was legitimate.
2.31 A few responses directly to the Department questioned the need for regulation in relation to water efficiency and whether it was appropriate for Government to regulate at all. Others were more positive and supported the concept, but with some discussion about the best methodology to use for improving water efficiency.
2.32 Part G of the Building Regulations has only recently been updated with the changes coming into force on 6 April this year and there has been no formal evaluation of how it is working in practice. In the absence of a compelling case, we do not propose to look at Part G in the coming year.
2.33 However, the Department has received representations about the Part G guidance on toilet provision, with a suggestion that the guidance (which cross- refers to the Health and Safety Executive Approved Code of Practice)discriminates against women. Whilst there is no evidence that the guidance leads to inadequate provision, we do intend to examine whether existing guidance on levels of provision of toilets for men and women is adequate. We will work closely with Health and Safety Executive in setting out the aims of and approach to this work.