|
The Office of the Deputy Prime Minister, ODPM, has already started the ball rolling with regard to updating the Building Regulations in 2005 & beyond.
Parts L1 & L2, Conservation of Fuel & Power), could be due for a further shake up if the following amendments are implemented.
1). A methodology for calculating the energy performance of buildings.
2). Setting energy performance standards for new and existing buildings.
3). Requiring more consideration of low-carbon and zero-carbon systems when constructing larger non-domestic buildings.
4). Introducing requirements for producing building energy certificates whenever buildings are built, leased or sold.
5). Setting up an inspection system for boilers rated at more than 20kW (or an information system that achieves similar results).
6). Setting up a routine inspection system for air conditioning systems of more than 12kW rated output.
Specifically in relation to Building Regulations, the White Paper announced the intentions of:-
1). Raising standards over the next decade, learning lessons from the standards in comparable European countries (Para 3.12)
2). Raising the standard required for new and replacement boilers to SEDBUK classes A or B (Para 3.13). The Government has since decided to bring this provision into effect by 01 April 2005.
3). Starting immediately on the next major revision of Part L, with the aim of bringing this into effect in 2005 (Para 3.16).
4). Seeing how the enforcement system might be improved to enable better correlation between design standards and as-built performance (Para 3.20).
Further considerations will also be shown towards:
Thermal Bridging
Given the increasing significance of thermal bridges, the current thinking is that the effects of thermal bridges should be quantified as part of the overall assessment of whole building energy performance. However it is recognised that simple ways of showing compliance and more comprehensive guidance will both be needed.
Airtightness standards
It is suggested that airtightness standards (measured as air permeability) need to be improved, and that different standards should be set for the different types of buildings, as suggested in CIBSE TM23 10. The level of improvement that might be justified is likely to be greater for the more energy intensive building types (e.g. commercial buildings as opposed to industrial ones, and balanced mechanically ventilated dwellings as opposed to naturally ventilated ones).
Pressure testing
In order to continue to achieve further improvements in the levels of airtightness found in practice, it is thought that it would be beneficial to expand the application of airtightness testing. There has been some confusion over the implementation of the guidance in the 2002 ADL2. Consideration is therefore being given to introducing a legal requirement to carry out pressure testing of buildings.
Dwellings - those builders that are not using Robust Details and a third party quality assurance system would need to demonstrate that sufficient airtightness has been achieved via a pressure test. In addition, if tests to be carried out during the next few months indicate that the adoption of robust details is not delivering the required standards (see paragraph 65), then pressure testing might be required even if robust details have been adopted. In all cases, testing would be done on a sample basis - perhaps modelled on the sampling provisions set out in the new Part E.
Other types of buildings with floor areas exceeding 200m2 should each be tested. (The current guidance is to test buildings over 1000m2. The 200m2 threshold matches the application area limit set in ADL2, 2002 for air conditioning. It also roughly matches in with the Directive Article 9 threshold of 12kW cooling output, being equivalent to a cooling load of 60W/m2.) We currently think that both of these new requirements could be implemented as part of the 2005 review.
Improved correlation between design and as-built performance
There is a measure of concern that there is often significant difference between the design assessment of energy performance and the performance achieved in practice. Focusing attention on improved design details and site supervision to improve the performance of thermal bridges and airtightness might help to improve the correlation. Other factors might include the robustness of assumptions about such factors as gaps between insulation, timber fractions etc.
Increasing the type and frequency of pre-completion testing to check that build quality matches the design intent, and the attention that building control inspectors pay to see that this is being done. This has implications for availability of test equipment, competent testers and resources for building control bodies etc.
Basing the performance standards on more realistic assumptions about build quality. This would mean that to achieve a given U-value, more insulation would be required to compensate for the defects in typical construction. Builders who reasonably demonstrate that their construction methods or systems deliver better build quality than the standard could use this to justify reducing insulation thickness. Such an approach has been used in Sweden and it is understood that similar provisions are in place in Holland
Appliances
It is clear that in many building types, the energy used by appliances (white and brown goods, business machines, personal computers etc) represents a very significant proportion of the energy budget and the carbon emissions. Currently, Building Regulations do not address the performance of appliances, although ODPM lawyers have advised that the powers available in the Building Act do not preclude so doing.
We propose to explore this issue in close collaboration with DEFRA's Market Transformation Team to see if Part L is the most appropriate mechanism for introducing performance standards for appliances and will report at a later date.
Swimming pools
Until now, Part L has only addressed those aspects of building design that provide comfort and convenience for normal occupant activities. In line with the aims of the EWP, we are looking to see what other activities within dwellings and other buildings might provide opportunities to achieve reductions in carbon emissions. Swimming pools and hot tubs (whether indoor or outdoor) are particularly suited to the application of no/low carbon systems such as solar hot water or CHP and can be significant users of energy in respect of such issues as:
a. Insulation of the pool basin
b. Provision of pool covers
c. Pool water heating system efficiency
d. Ventilation heat recovery.
We are therefore giving consideration to whether standards could be defined for swimming pools and hot tubs (and whether they would yield worthwhile and cost-effective carbon savings).
U-values
For new build, the aim is to express the reasonable standard of provision for the whole building using the SAP energy and/or carbon methods leaving designers to follow their own inclinations on how best to achieve it, whilst keeping within constraints of poorest acceptable U-values. In establishing the whole-building performance standard it will be necessary to analyse a range of house types constructed to reasonable elemental standards. The following paragraphs describe what those elemental standards might be. Smaller builders may wish to continue using an elemental-based method, and U-value standards will still be necessary for use in alteration and extension work.
Much attention has been given to the need to improve the existing stock if the Kyoto targets are to be met. Such attention is necessary, but dwellings built now will have a service life well beyond 2050, and it is important that they make a reasonable contribution to achieving the 2050 target. Consequently, the stock that is built between now and 2050 has to be of the best practical standard.
We think that 2005 may be too soon to raise window standards for replacement work because of handling and fabrication issues associated with soft coat technologies, and the difficulties associated with soft coating toughened glass. We therefore think that for replacement windows, the performance standard should be kept at the current level as set out in ADL1(2002), (i.e. 2.0 W/m2K for wood and PVCU windows and 2.2 for metal ones) - at least until the originally targeted 5 years period between the 2002 implementation and the next revision of Part L has passed (i.e. April 2007). However, we propose that the improved standard would apply to new building work immediately following the implementation date. This approach should keep the costs of replacement windows at their current level, thereby not discouraging homeowners from investing in replacements. The period up to 2007 would allow industry to expand their soft-coat production technologies as the market for such windows expands.
Airtightness
The levels of airtightness achieved in some new dwellings is to be monitored over the next few months to help establish whether the "Robust Details" published by TSO in 2001 are delivering satisfactory As-Built performance. If there is insufficient confidence that the standards mentioned in paragraph 35 will be achieved in practice, then we would consider introducing sample pressure testing of dwellings in the 2005 amendment.
Central heating boilers
For domestic gas boilers serving space-heating systems, the EWP has indicated that the standard for normal circumstances will be increased to SEDBUK Band A or B (i.e. a seasonal efficiency >= 86%), which is equivalent to a condensing boiler. The Government has indicated that it wants this higher standard brought into effect by 01 April 2005 so that boilers can be removed from the prospective new Energy Efficiency Commitment signalled in the EWP. We shall therefore be developing proposals for an interim amendment timed to come into effect on 01 April 2005, that revises the guidance in ADL1 (2002). The aim is to consult on this as part of the general consultation on Part L in the summer of 2004, and then to fast-track the review and approval process to enable the amendment to be published around February 2005.
It will be necessary as part of this to introduce separate provisions for different classes of boilers such as back boilers, combi-boilers and central hot water storage units, and boilers fired with LPG, oil, or solid fuel. Multi-fuel solid fuel boilers will need particular consideration, given the very different carbon intensity of the alternative fuels (coal, wood and wood pellets).
We also think it essential to make reasonable provision when microCHP units (or other new heating technologies) are to be installed. As part of this process, SAP 2001 will need to be updated to reflect the performance of mature new technologies as well as to align it with the requirements of the EPBD.
The EWP encourages the greater uptake of renewable energy systems, and so we will be exploring what guidance might be appropriate for other types of building integrated renewable energy technology. The most likely candidate is PV generating systems , and as with solar hot water, where the economics are favourable, consideration might be given to requiring some PV provision, or at least making it practical to more easily incorporate PV as a later retrofit. Either way, ADL1 will provide references to documents that give advice on the selection and installation of various types of renewable energy system.
Refurbishment of the existing stock
There are around twenty four million existing dwellings and the average SAP Rating of this stock is around 44. New dwellings built to the 1995 standards were achieving SAP Ratings on average perhaps around 75, and those being designed to the 2002 standards may be achieving SAP Ratings up to around 90. However less than 200,000 new dwellings are being built in the UK each year. Examining how further encouragement can be given towards improving the average SAP Rating of the existing stock is therefore seen to be a vital element of this review.
Regular inspection of boiler plant
The EPBD offers member states two routes to achieving this goal and discretion on which fuelling options trigger the inspection requirement. There are options of an inspection regime or a system of advice to users that will achieve the same objective, namely delivering recommendations on cost-effective improvements to, or replacements of, the heating system to improve energy efficiency. The EPBD Article allows that inspection systems can be limited to apply to oil and solid fuelled installations or opened up to include gas. As an urgent first step DEFRA are preparing a statement of the merits and demerits of the options so that Ministers can decide which is most appropriate for the UK.
Air conditioning and mechanical ventilation (ACMV)
The performance standards given in ADL2 (2002) for buildings that are air-conditioned or mechanically ventilated (ACMV) were equivalent to what was considered "typical" performance in 1998. The application of ACMV in new and existing buildings continues to expand rapidly (and may accelerate should climate change effects become more manifest). Higher standards for effective design and appropriate commissioning are therefore being considered.
Because of the growth in multiple split systems that can serve small individual rooms, our current thinking is that the limit on application of the requirement should be reduced. The present limit of 200 m2 was derived from considerations of minimum lettable areas. The limit might be reduced to say 100 m2, or might instead be based on considerations of fan or refrigeration capacities. For example, the EPBD requirement on inspection of air-conditioning systems covers those systems with an output greater than 12kW, and there may be benefit in having a consistent application limit.
Regular inspection of air conditioning systems
In line with the EPBD, we will be developing proposed legal requirements and technical guidance for reasonable provision for regularly inspecting and reporting on air conditioning systems rated at more than 12 kW. The guidance might be included in ADL2 or could be published as perhaps a CIBSE or FETA Technical Memorandum. CIBSE and FETA are already working on this. This would be underpinned by deploying dormant powers in Section 2 of the Building Act, perhaps amended by the European Communities Act 1972.
Renewable energy systems
We are investigating how the Building Regulations can address the requirement in the EPBD Article 5 to take into account low-Carbon and Zero-Carbon technologies at the design stage Various ways that have been suggested include
a. Setting the building energy performance standard based on a proportion of the building's energy demand being generated from an onsite renewable source. This would require designers to include renewable or low-carbon energy systems as part of the design, or else compensate via higher energy efficiency standards in other aspects of the design. This approach has the advantage of allowing market forces to determine the most cost effective
way of achieving carbon savings.
b. Setting a limit on the externally supplied power input to the building, requiring buildings with high power demands to have building integrated energy generation capacity. This approach has been used in other countries (e.g. parts of Switzerland), but has the disadvantage of being more to do with building use than building design.
Further guidance is to be developed on the selection and application of a number of lowcarbon and zero-carbon technologies that can be used as part of achieving the requisite overall building carbon performance.
Where such no or low carbon technologies are installed, we think that for the time being, such provisions should not be used via trade-off to reduce the fundamental efficiency of the building envelope or the building services systems.
The above information has been reproduced in part from the ODPM 'Possible Future Performance Standards for Part L October 2003' consultative document, under our HMSO licence C02W0003643
|
