Archived Approved document part L: 2014 (incorporating 2016 amendments) L2A (new buildings other than dwellings)

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Conservation of fuel and power

L2A

Approved Document

New buildings other than dwellings

In effect from July 2014

2014 Edition incorporating 2016 amendments

For use in Wales*

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This approved document, Approved Document L2A: Conservation of fuel and power in new buildings other than dwellings supports the energy efficiency requirements of the Building Regulations. Regulation 2(1) of the Building Regulations defines the energy efficiency requirements as the requirements of regulations 23, 25A, 25B, 26, 26A, 26B, 28, 29 and 40 and Part L of schedule 1. It takes effect on 31 July 2014 and is for use in Wales*. The 2010 edition will continue to apply to work begun before 31 July 2014, or to work subject to a building notice, full plans application or initial notice submitted before 31 July 2014.

The main changes in the approved document are that:

•A new requirement, regulation 26A has been introduced that requires new non-domestic buildings to achieve or better the target primary energy consumption rate.

•The Part L 2014 specifications have been strengthened to deliver 20% carbon dioxide savings across the new non domestic build mix relative to Part L 2010.

•A wider set of notional buildings has now been defined for top-lit, side-lit (heated only) and side-lit (heated and cooled) buildings. The notional building air permeability has been further sub-divided by size.

•A summary of the Part L 2014 elemental specification of these notional buildings is published at Appendix B in the Approved Document. If the actual building is constructed entirely to the notional building specifications it will meet the carbon dioxide and primary energy consumption targets and the limiting values for individual fabric elements and building services. Developers are however free to vary the specification, provided the same overall level of primary energy consumption and carbon dioxide emissions is achieved or bettered.

•The document consolidates the amendments made in SI 2013/747 requiring the feasibility of high efficiency alternative systems to be taken into account before construction commences.

•The document is in a new style format.

Main changes made by the 2016 amendments

Changes reflect alterations to the regulations, principally withdrawal of Regulations 29 to 33 of the Building Regulations 2010 and their replacement by Regulation 7A of the Energy Performance of Buildings (England and Wales) Regulations 2012 and changes in wording of Regulations 24, 25, 26, 26A, 26B, 27A and 27B of the Building Regulations 2010. There are no technical changes.

© Crown copyright 2016 WG29013 Digital ISBN 978-1-4734-6798-9

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Page

Section 1 – Introduction 3

1.1What is an Approved document? 3 1.2 Conventions within this Approved Document 3

1.3Types of work covered by an Approved Document 4 1.4 Summary of the Approved Document 5 1.5 Consideration of technical risk 6

1.6Materials and Workmanship 6

1.7Where you can get further help 8

1.8Responsibility for compliance 8

Section 2 – Compliance criteria 9

2.1Introduction 9

2.2Criteria for compliance 10

Section 3 – Criteria 1 – The BPEC and BER must be no greater 11 than the TPEC and TER

3.1Introduction 11

3.2Calculating the BPEC and BER before commencement of work 14

3.3Calculating BPEC and BER after completion 17

3.4Benefits of enhanced energy management 17

3.5Conservatories and porches 17

3.6Swimming pools 18

3.7Modular and portable buildings with a planned service life of 18 more than two years

3.8Shell and core developments 19

3.9Buildings with a low energy demand 20

3.10Industrial sites, workshops and non-residential agricultural 21 buildings other than those with a low energy demand

3.11Extensions 21

3.12Demonstrating compliance 22

Section 4 – Criteria 2 – Limits on design flexibility 23

4.1Introduction 23

4.2Building fabric 24

4.3Fixed building services 24

4.4Demonstrating compliance 26

Section 5 – Criterion 3 – Limiting the effect of heat gains 27

5.1Limiting the effect of solar gains during the summer 27

Section 6 – Criterion 4 – Building construction and performance 29 consistent with BER

6.1Introduction 29

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6.2Limiting thermal bypasses 29

6.3Thermal bridging 29

6.4Air-pressure testing 30

6.5Commissioning of building services 33

Section 7 – Criterion 5 – Providing energy efficient operation 36 of buildings

7.1Introduction 36

7.2Building log book 36

Section 8 – Calculating Target Primary Energy 37

Consumption (TPEC) and the Target CO 2 Emissions Rate (TER)

8.1Introduction 37

8.2Conservatories and porches 38

8.3Swimming pools 38

Section 9 – Buildings Exempt from the Energy Efficiency 39

Requirements

9.1Introduction 39

9.2Places of worship 39

9.3Temporary buildings 39

9.4Industrial sites, workshops and non-residential agricultural buildings 39 with a low energy demand

9.5Conservatories and porches 40

9.6Stand-alone buildings 40

Section 10 – Notifying Building Control and demonstrating 41

Compliance

10.1Introduction 41

10.2Cases where notification is not needed – Competent Person 42

Scheme

Appendix A: Key terms and definitions 43

Appendix B: Elemental specification for the TER calculation 47

Appendix C: Calculating U values 49

Appendix D: Materials and Workmanship 50

Appendix E: The Workplace (Health, Safety and Welfare) 51

Regulations 1992

Appendix F: Approved Documents 52

Appendix G: Documents and standards referred to 53

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1.1What is an Approved Document?

1.1.1This Approved Document, which takes effect on 31 July 2014, has been approved and issued by the Welsh Ministers to provide practical guidance on ways of complying with the energy efficiency requirements of the Building Regulations 2010 for Wales as amended, which are referred to throughout the remainder of this document as ‘the Building Regulations’.

1.1.2Approved Documents provide guidance about compliance with specific aspects of the Building Regulations in some of the more common building situations. They set out what, in ordinary circumstances, may be accepted as reasonable provision for compliance with the relevant requirement(s) to which they refer. The term ‘reasonable provision’ is used in the Approved Documents because the specific evidence or standards required to demonstrate compliance are not generally stipulated by the Building Regulations themselves. Approved Documents describe one way of complying with the Building Regulations.

1.1.3If guidance in an Approved Document is followed there will be a presumption of compliance with the requirement(s) of the Building Regulations covered by the guidance. However, this presumption can be overturned; for example, if the particular case is unusual in some way, then ‘normal’ guidance may not be applicable. It is also important to note that there may be other ways of achieving compliance with the requirements. There is no obligation to adopt any particular solution contained in this Approved Document if you can meet the relevant requirement(s) in some other way. However, you must always check with your Building Control Body (BCB), either the local authority or an approved inspector, that your proposals comply with Building Regulations.

1.1.4As well as containing guidance, the Approved Documents also contain relevant extracts from the Building Regulations that must be complied with as stated. For example, the requirement that the target primary energy consumption (TPEC) and the target carbon dioxide (CO 2) emission rate (TER) for the building shall not be exceeded is a regulatory requirement.

1.1.5This Approved Document is concerned with energy efficiency requirements. However, building works to new non-domestic buildings may be subject to requirements of other sections of the Building Regulations, for instance fire safety, site preparation and ventilation. There are Approved Documents that give guidance on each of the requirements of the Building Regulations and all of these must be consulted when building works are considered. A full list of these is provided in Appendix F: Approved Documents.

1.2 Conventions within this Approved Document

1.2.1This document uses the following conventions

a.Text against a grey background is an extract from the Building Regulations 2010 or the Building (Approved Inspector etc.) Regulations 2010 (both as amended). These extracts set out the legal requirements of the regulations. Where there is any doubt you should consult the full text of the regulations available at www.legislation.gov.uk.

b.Key terms which have specific meanings are used in bold italics in the text and

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•defined in Appendix A.

c.When this Approved Document refers to a named standard or other document, the relevant version is listed in Appendix G (Documents and Standards referred to). However, if the issuing body has revised or updated the listed version of the standard, you may use the new version as guidance if it continues to address the relevant requirements of the Building Regulations.

d.Additional commentary in italic text appears after some numbered paragraphs. This commentary is intended to assist understanding of the immediately preceding paragraph or sub-paragraph, or to direct readers to sources of additional information, but is not part of the technical guidance itself.

1.3Types of work covered by this Approved Document

1.3.1 This Approved Document gives guidance on how to comply with the energy efficiency requirements for the following works on non-domestic buildings (i.e. buildings that are not dwellings):

a.Construction of new non-domestic buildings.

b.Fit-out works where the work is either part of the construction of a new non- domestic building, or is the first fit-out of a shell and core development where the shell is sold or let before the fit-out work is carried out. (Approved Document L2B applies to fit-out works of non-domestic buildings in other circumstances.)

c.The construction of extensions to existing non-domestic buildings where the total useful floor area of the extension is greater than 100 m² and greater than 25 per cent of the total useful floor area of the existing building.

For those carrying out all other building work on existing non-domestic buildings, Approved Document L2B should be used.

1.3.2Approved Document L1A should be used for guidance in relation to each individual dwelling where one or more dwelling is constructed as part of a larger building. Approved Document L2A gives guidance related to the non-dwelling part of such buildings. This would include heated common areas in an apartment building and commercial and retail space of mixed use developments.

1.3.3In this Approved Document, dwelling refers to a self-contained unit (including a house or a flat) designed to be used separately to accommodate a single household. Rooms for residential purposes, for example in nursing homes, student accommodation, etc., are not dwellings, and guidance for such buildings is given in this Approved Document.

1.3.4‘Live-work’ units containing both living accommodation and space to be used for commercial purposes (e.g. workshop or office) should be assessed as a dwelling as long as the commercial part could revert to domestic use. This could be the case if, for example:

a.there is direct access between the commercial space and the living accommodation; and

b.both are contained within the same heated (and/or cooled) space; and

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c.the living accommodation forms a substantial proportion of the total area of the unit.

Note: Interpretation of the above is that the presence of (e.g.) a small manager’s flat in a large non-domestic building would not result in the whole building being treated as a dwelling. Similarly, the existence of a room used as an office or utility space within a dwelling would not mean that the building should not be treated as a dwelling. However, if a small office, say a manager’s office, is located within a block of apartments, i.e. for multiple households, this component will be assessed as a non-domestic building, guidance for which is given within this Approved Document.

1.3.5The energy efficiency requirements apply to buildings or parts of buildings that are walled and roofed constructions and use energy to heat or cool the indoor climate, otherwise referred to as ‘conditioned’ space within this document. Other building works are exempt as are some buildings with special characteristics. Buildings with exemptions are listed below but it is important to check Section 9 and discuss with your Building Control Body to ensure that you fully meet the criteria for exemption.

a.Buildings which are used primarily or solely as places of worship

b.Temporary buildings with a planned time of use of 2 years or less

c.Industry sites, workshops and non-residential agricultural buildings with low energy demand

d.Stand-alone buildings other than dwellings with a total useful floor area of less than 50m 2

e.Carports, covered yards, covered ways and some conservatories and porches

1.3.6In addition, special considerations apply to certain classes of non-exempt buildings.

a.Modular and portable buildings with a service life of use of more than two years (see section 3.7)

b.Shell and core developments (see section 3.8)

c.Non-exempt buildings with low energy demand (see Section 3.9)

d.Industrial sites, workshops and non-residential agricultural buildings other than those with low energy demand (see Section 3.10)

1.4 Summary of the Approved Document

1.4.1This Approved Document is subdivided into ten sections that are followed by supporting appendices. It gives guidance on how to comply with the energy efficiency requirements for common building works to new non-domestic buildings.

Section 1 - this introductory section sets out the general context in which the guidance in the Approved Document must be considered.

Section 2 - explains the five criteria within this Approved Document that would need to be complied with to satisfy the energy efficiency requirements.

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Section 3 - explains how the primary energy consumption and CO2 emissions rate for buildings can be calculated to ensure that it does not exceed their targets (Criterion 1).

Section 4 - sets minimum energy efficiency standards for building fabric and services (Criterion 2).

Section 5 - describes how to reduce the risk of overheating in buildings and thus the need for energy for cooling (Criterion 3).

Section 6 - sets out procedures to help ensure that the actual performance of the constructed building is as designed (Criterion 4)

Section 7 - sets out information to be provided to the occupier so that the building can be operated in an energy efficient manner (Criterion 5)

Section 8 - describes how the Criterion 1 targets are determined: the target primary energy consumption and the target CO 2 emissions rate.

Section 9 - describes which buildings are exempt from the energy efficiency requirements.

Section 10 - sets out the procedures for notifying building control.

1.4.2The following flow chart overleaf provides a summary of the information contained within the various Sections of this Approved Document.

1.5 Considerations of technical risk

1.5.1When considering the incorporation of energy efficiency measures in non- domestic buildings, attention should also be paid to interrelated issues such as fire safety, resistance to the passage of sound, ventilation, hot water supply and systems, combustion appliances and fuel storage systems, water ingress and possible risk of condensation and electrical safety. It is important to consider the non-domestic building as a whole and understand the interaction between all the relevant requirements of the Building Regulations. For example, where work carries a risk of condensation, such risk must be effectively mitigated by careful specification of the construction and if necessary the ventilation system for the non-domestic building; one approach would be to follow the guidance set out in BRE Report 262 Thermal Insulation: Avoiding the risks (see Approved Document C for more details).Designers and builders should refer to the relevant approved documents and to other generally available good practice guidance to help minimise these risks

1.6Materials and Workmanship

1.6.1In accordance with regulation 7, building work must be carried out in a workmanlike manner using adequate and proper materials. See Appendix D for further information.

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1.7.1If you do not understand the technical guidance or other information set out in this Approved Document and the additional detailed technical references to which it directs you, there are a number of routes through which you can get further help:

a.the Welsh Government website : www.wales.gov.uk/topics/planning/buildingregs; or

b.your local authority building control service or your approved inspector (depending on which building control service you are using); or

c.persons registered with a competent person self-certification scheme may be able to get technical advice from their scheme operator; or

d.if your query is of a highly technical nature, you may wish to seek the advice of a specialist, or industry technical body, for the relevant subject.

1.8 Responsibility for compliance

1.8.1It is important to remember that if you are a person carrying out any aspect of design or building work to which any requirement of the Building Regulations applies (for example a designer, a builder or an installer) you have a responsibility to ensure that the work complies with any such requirement. The person undertaking the work also has a responsibility for ensuring compliance with the Building Regulations and could be served with an enforcement notice in cases of non-compliance.

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Requirement

Schedule 1 – Part L Conservation of fuel and power

L1.Reasonable provision shall be made for the conservation of fuel and power in buildings by:

(a) limiting heat gains and losses—

(i) through thermal elements and other parts of the building fabric; and

(ii) from pipes, ducts and vessels used for space heating, space cooling and hot water services;

(b) providing fixed building services which—

(i) are energy efficient;

(ii) have effective controls; and

(iii) are commissioned by testing and adjusting as necessary to ensure they use no more fuel and power than is reasonable in the circumstances.

2.1.1This Approved Document deals with the energy efficiency requirements in the Building Regulations 2010 (as amended). Energy efficiency requirements are defined as the requirements of regulations 23, 25A, 25B, 26, 26A, 26B, 28 and 40 and Part L of Schedule 1, to the Building Regulations. The energy efficiency requirements relevant to this Approved Document, which deals with new buildings, are those in regulations 25, 25A, 26, 26A and 40 and Part L of Schedule 1 above.

Regulation 25B “Nearly zero-energy requirements for new buildings” will not come into force until 2019 at the earliest. Statutory guidance on compliance with Regulation 25B is not included within this Approved Document and will be provided nearer to the time it comes into force.”

2.1.2In the Welsh Minister’s view, compliance with the energy efficiency requirements could be demonstrated by meeting all five criteria set out in this Approved Document. It is expected that approved software will produce an output report that will assist the Building Control Body (BCB) to check that compliance has been achieved.

This output report can also benefit both developers and Building Control Bodies during the design and construction stages as well as at and after completion.

2.1.3Of the five criteria explained in this document, the approaches described to meet the following criteria are within regulations and must be complied with as stated:

a.Criterion 1; and

b.Parts of Criterion 4 dealing with air-pressure testing and commissioning requirements.

2.1.4The approaches to meet the other criteria are ‘reasonable provision’ and alternative proposals are permissible, which should be checked with the BCB to confirm that they meet the energy efficiency requirements.

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2.2.1Criterion 1: both of the following conditions must apply by following the procedures set out in Sections 3 and 8:

a.the calculated primary energy consumption (the Building Primary Energy Consumption, BPEC) must not be greater than the Target Primary Energy Consumption (TPEC); and

b.the calculated the calculated CO 2 emissions rate for the building (the Building Emission Rate, BER) must not be greater than the Target Emission Rate (TER).

Note: The calculations required to show compliance with Criterion 1 can also provide the information needed to prepare the Energy Performance Certificate or EPC for buildings.

2.2.2Criterion 2: the performance of the building fabric and the fixed building services should achieve reasonable minimum energy efficiency standards following the procedure set out in Section 4.

This is intended to place limits on design flexibility to encourage the reduction of demand for space heating (and cooling) and efficient use of fuel and discourage excessive use of renewable energy solutions.

2.2.3Criterion 3: the building should have appropriate passive control measures to limit the effect of solar and other heat gains on indoor temperatures in summer. This is to help reduce the need for, or installed capacity of, mechanical cooling and the associated energy consumption. Section 5 provides guidance on reasonable provision to meet this criterion.

2.2.4Criterion 4: the performance of the building, as built, should be consistent with the calculated BPEC and BER. Section 6 provides information on site management and testing procedures that would need to be adopted to demonstrate that the performance of the building fabric and fixed building services will be consistent with the specification used for energy performance evaluation.

2.2.5Criterion 5: information necessary to enable the energy-efficient operation of the building should be provided to the occupier in an easy to understand format. Section 7 includes guidance on the information that could be included by way of reasonable provision to demonstrate compliance with this criterion.

2.2.6Sections 3 to 7 include details of how to demonstrate that each of the criteria has been met. Further details on communicating this to BCBs are included in Section 10.

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Regulation 26 – CO 2 emission rates for new buildings

Where a building is erected, it shall not exceed the target CO 2 emission rate for the building that has been approved pursuant to regulation 25, applying the methodology of calculation and expression of the energy performance of buildings approved pursuant to regulation 24.

Regulation 26A – Primary energy consumption rates for new buildings

Where a building (other than a dwelling) is erected, it must not exceed the target primary energy consumption rate for the building which has been approved pursuant to regulation 25C (a), applying the methodology of calculation and expression of the energy performance of buildings approved pursuant to regulation 24.

3.1.1Criterion 1 is a mandatory requirement and must be met by all new buildings as stated.

3.1.2To comply with regulation 26A and regulation 26 it will need to be demonstrated that:

a.the calculated Building Primary Energy Consumption (BPEC) rate does not exceed the Target Primary Energy Consumption (TPEC); and

b.the calculated Building CO2 Emissions Rate (BER) rate does not exceed the Target CO2 Emissions Rate (TER)

3.1.3This section focuses on the calculation of the BPEC and the BER. Details of how the TPEC and TER are calculated are set out in Section 8. Special considerations for specific building categories are given in sections 3.7 to 3.10.

This update to the Approved Document maintains the approach to setting the TER adopted in 2010 whereby the TER is based on an elemental set of specifications to which no additional improvement factor is applied The specifications now include an area of roof mounted photovoltaic panels.

3.1.4In accordance with the methodology approved by the Welsh Ministers in the Notice of Approval, the primary energy consumption and CO 2 emission rates for individual buildings must be calculated using one of the following approved software tools and using the primary energy factors and CO 2 emission factors as published by DECC1.

a.The Simplified Building Energy Model (SBEM)2 for those buildings whose design features are capable of being adequately modeled by SBEM; or

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b.Other approved software tools which can be found on the Department of Communities and Local Government website at www.communities.gov.uk.

3.1.5As part of the submission to a BCB, the applicant must show that the software tool used is appropriate to the application.

3.1.6Provided the building satisfies the limits on design flexibility as set out in Criterion 2, the designer flexibility to achieve the BPEC and the BER utilising fabric and services measures and the integration of low and zero carbon technologies in whatever mix is appropriate to the scheme. Approved software tools include appropriate algorithms that enable the designer to assess the role each of these technologies can play in achieving the TPEC and TER.

3.1.7To encourage incorporation of improvements in building services system efficiencies and the integration with low and zero carbon technologies, the designer should:

a.consider incorporating heating and cooling system designs that use low distribution temperatures; and

b.where multiple systems serve the same end use, organise the control strategies such that priority is given to the least carbon-intensive option, for example where a solar hot water system is present, the controls should be arranged so that the best use is made of the available solar energy; and,

c.consider making the building easily adaptable for the integration of additional low and zero carbon technologies at a later date by providing appropriate facilities at the construction stage that would make subsequent enhancements much easier and cheaper, e.g. providing capped off connections that can link into a planned community heating scheme.

Regulation 25A - Consideration of high-efficiency alternative systems for new buildings

(1) Before construction of a new building starts, the person who is to carry out the work must analyse and take into account the technical, environmental and economic feasibility of using high-efficiency alternative systems (such as the following systems) in the construction, if available—

(a) decentralised energy supply systems based on energy from renewable sources;

(b) cogeneration;

(c) district or block heating or cooling, particularly where it is based entirely or partially on energy from renewable sources; and

(d) heat pumps.

(2) The person carrying out the work must—

(a) not later than the beginning of the day before the day on which the work starts, give the local authority a notice which states that the analysis referred to in paragraph (1)—

(i) has been undertaken;

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(ii) is documented; and

(iii) the documentation is available to the authority for verification purposes; and

(b) ensure that a copy of the analysis is available for inspection at all reasonable times upon request by an officer of the local authority.

(3) An authorised officer of the local authority may require production of the documentation in order to verify that this regulation has been complied with.

(4) The analysis referred to in paragraph (1)—

(a) may be carried out for individual buildings or for groups of similar buildings or for common typologies of buildings in the same area; and

(b) in so far as it relates to collective heating and cooling systems, may be carried out for all buildings connected to the system in the same area.

(5) In this regulation—

(a) “cogeneration” means simultaneous generation in one process of thermal energy and one or both of the following—

(i) electrical energy;

(ii) mechanical energy;

(b) “district or block heating or cooling” means the distribution of thermal energy in the form of steam, hot water or chilled liquids, from a central source of production through a network of multiple buildings or sites, for the use of space or process heating or cooling;

(c) “energy from renewable sources” means energy from renewable non-fossil sources, namely wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases; and

(d) “heat pump” means a machine, a device or installation that transfers heat from natural surroundings such as air, water or ground to buildings or industrial applications by reversing the natural flow of heat such that it flows from a lower to a higher temperature. (For reversible heat pumps, it may also move heat from the building to the natural surroundings.)

3.1.8Regulation 25A requires that before the work starts, the person undertaking the work must carry out an analysis that considers and takes into account the technical, environmental and economic feasibility of using high-efficiency alternative systems in the construction. The following high efficiency alternative systems may be considered if available, but other low and zero carbon systems may also be considered if available:

•decentralised energy supply systems based on energy from renewable sources;

•cogeneration;

•district or block heating or cooling, particularly where it is based entirely or partially on energy from renewable sources;

•heat pumps.

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3.1.9The analysis should state whether high-efficiency alternative systems have or have not been included in the building design. The requirement relates to considering, taking into account, documenting and making available for verification purposes the analysis of high-efficiency alternative systems.

The Building Regulations are technology neutral and do not mandate the installation of high efficiency alternative systems or other low and zero carbon systems. However, the design and construction of new buildings may feature such systems to meet local interpretations of Planning Policy Wales conditions that require specific energy performance standards exceeding the Building Regulations and/or require a proportion of energy used in development to be from renewable and/or low carbon sources.

3.1.10The analysis of using high-efficiency alternative systems may be carried out for individual buildings, groups of similar buildings or for common types of buildings in the same area. Where a number of buildings are connected to a community energy system, a single analysis may be carried out for all of the buildings connected to the system in the same area as the building to be constructed.

3.1.11Before work starts, the person undertaking the work shall give the BCB a notice which states that the analysis of using high-efficiency alternative systems has been undertaken, is documented and is available for verification purposes. The results of the analysis must be documented and retained for inspection by the BCB upon request.

Although the analysis of high efficiency alternative systems is not an explicit requirement of the CO 2 emission rate calculation, a facility within calculation software output reporting (the design stage Building Regulation Part L report) may be available to the builder to declare that the analysis has been carried out, is documented and where it is available for verification purposes.

3.1.12Similarly the designer should consider the potential impact of future climate change on the performance of the building. This might include giving consideration to how a cooling system might be provided at some future point.

3.2 Calculating BPEC and BER before commencement of work

Regulation 27 - CO 2 emission rate calculations

(1) This regulation applies where a building is erected and regulation 26 applies.

(2) Not later than the day before the work starts, the person carrying out the work shall give the local authority a notice which specifies–

(a) the target CO 2 emission rate for the building, calculated and expressed in accordance with the methodology approved pursuant to regulation 24,

(b) the CO 2 emission rate for the building as designed , calculated and expressed in accordance with the methodology approved pursuant to regulation 24, and

(c) a list of specifications to which the building is to be constructed.

(3) Not later than five days after the work has been completed, the person carrying out the work shall give the local authority–

(a). notice which specifies–

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i. the target CO 2 emission rate for the building, calculated and expressed in accordance with the methodology approved pursuant to regulation 24, ii. the CO 2 emission rate for the building as constructed, calculated and expressed in accordance with the methodology approved pursuant to regulation 24, and iii. whether the building has been constructed in accordance with the list of specifications referred to in paragraph (2) (c), and if not a list of any changes to those specifications; or

(b) a certificate of the sort referred to in paragraph (4) accompanied by the information referred to in sub-paragraph (a).

(4) A local authority is authorised to accept, as evidence that the requirements of regulation 26 have been satisfied, a certificate to that effect by an energy assessor who is accredited to produce energy performance certificates for that category of building.

(5) In this regulation ‘specifications’ means specifications used for the calculation of the

CO 2 emission rate.

Regulation 27A - Primary energy consumption rate calculations

(1) This regulation applies where a building (other than a dwelling) is erected and regulation 26A applies.

(2) Not later than the day before the work starts, the person carrying out the work must give the local authority a notice which specifies—

(a) the target primary energy consumption rate for the building, calculated and expressed in accordance with the methodology approved pursuant to regulation 24;

(b) the primary energy consumption rate for the building as designed, calculated and expressed in accordance with the methodology approved pursuant to regulation 24; and

(c) a list of specifications to which the building is to be constructed.

(3) Not later than five days after the work has been completed, the person carrying out the work must give the local authority—

(a) a notice which specifies—

(i) the target primary energy consumption rate for the building, calculated and expressed in accordance with the methodology approved pursuant to regulation 24;

(ii) the primary energy consumption rate for the building as constructed, calculated and expressed in accordance with the methodology approved pursuant to regulation 24;

and

(iii) whether the building has been constructed in accordance with the list of specifications referred to in paragraph 2(c), and if not a list of any changes to those specifications; or

(b) a certificate of the sort referred to in paragraph (4) accompanied by the information referred to in sub-paragraph (a).

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(4) A local authority is authorised to accept, as evidence that the requirements of regulation 26A have been satisfied, a certificate to that effect by an energy assessor who is accredited to produce energy performance certificates for that category of building.

(5) In this Regulation, “specifications” means specifications used for the calculation of the primary energy consumption rate.

.

3.2.1Regulations 26, 26A, 27 and 27A require that a calculation must be carried out before commencement of construction work to demonstrate that the BPEC and the BER of the building as-designed are no greater than the TPEC and the TER.

3.2.2Where fixed building services systems are capable of being fired by more than one fuel, then:

a.Where a biomass heating appliance is supplemented by an alternative appliance (e.g. gas), the CO 2 emission factor for the overall heating system should be based on a weighted average for the two fuels based on the anticipated usage of those fuels. The BER submission should be accompanied by a report, signed by a suitably qualified person, detailing how the combined CO 2 emission factor has been derived.

b.Where the same appliance is capable of burning both biomass fuel and fossil fuel, the CO 2 emission factor for dual fuel appliances should be used, except where the building is in a smoke control area, when the anthracite figure should be used.

c.In all other cases, the fuel with the highest CO 2 emission factor should be used.

Note: This option is to cover dual fuel systems, where the choice of fuel actually used depends on prevailing market prices.

3.2.3If thermal energy is supplied from a district or community heating or cooling system, primary energy factors and CO 2 emission factors should be determined by considering the particular details of the scheme.

a.Calculations should take account of the annual average performance of the whole system (i.e. the distribution circuits and all the heat generating plant, including any Combined Heat and Power (CHP), and any waste heat recovery or heat dumping). The design-stage predicted effect of all buildings proposed to be newly connected to the system in the first year of operation is to be included in the calculation of the primary energy and CO 2 emission factors so that the increased operation of any marginal plant (e.g. gas boilers) is properly accounted for.

b.The electricity generated by any CHP or trigeneration scheme is always credited at a primary energy and CO 2 emission factor equal to the grid average. CO 2 emissions associated with the thermal energy streams of a trigeneration scheme should be attributed in proportion to the output energy streams. The BPEC and BER submission should be accompanied by a report, signed by a suitably qualified person, detailing how the emission factors have been derived.

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Note: This means that if a district heating scheme burns F kWh of input fuel to produce E kWh of electricity and H kWh of useful heat (excluding heat rejected), the emission factor for the heat output should both be taken as 1/H*(F*CO 2F - E*CO 2E ) where CO 2F is the emission factor for the input fuel, and CO 2E the factor for grid electricity3.

3.3 Calculating BPEC and BER after completion

3.3.1The final BPEC/BER calculation produced in accordance with the guidance in this document must be based on the building, as constructed, incorporating:

a.any changes that have been made during construction from the design-stage list of specifications; and

b.the assessed air permeability, duct work leakage and commissioned fan performance as described in Section 6.

3.4Benefits of enhanced energy management

3.4.1Certain management features offer improved energy efficiency in practice. Where these management features are provided in the actual building, the BPEC and BER can be reduced by an amount equal to the product of the factor given in Table 1 and the CO 2 emissions for the system(s) to which the feature is applied.

3.4.2For example, if the CO2 emissions due to electrical energy consumption were 70 kgCO 2/(m².year) without power factor correction, the provision of correction equipment to achieve a power factor of 0.95 would enable the BER to be reduced by 70 x 0.025 = 1.75 kgCO 2/(m².year).

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3.5.1Conservatories and porches should be included in the BPEC/TPEC and BER/TER calculations only if they are constructed at the same time as a new building; and

a.There is no thermal element between the building and the conservatory and/or porch; or

b.the conservatory or porch contains no fixed heating appliance or the buildings heating system is not extended into the conservatory or porch.

3.6Swimming pools

3.6.1Where a swimming pool is constructed as part of a new building, the building should be assessed as if the pool basin was not present, while the pool hall should be included in the calculation of the BPEC and BER. The area covered by the pool basin should be taken into account in the calculation, as an equivalent area of floor with a U- value equal to that of the pool surround.

3.7Modular and portable buildings with a planned service life of more than two years

3.7.1Special considerations apply to modular and portable buildings with a planned service life greater than 2 years (exemptions for temporary buildings with a total service life of two years or less are given in section 9). The placing of an existing module to a new site is considered to be the construction of a new building as far as the Building Regulations are concerned. In that context, it is not always appropriate to expect such a relocated unit to meet the new-build standards set out in this Approved Document, especially as the embodied energy in an existing module is retained, a benefit that compensates for small differences in operating energy demand. Furthermore, portable buildings are often ‘distress purchases’, and the constraints imposed by the time in which a working building must be delivered mean that additional considerations apply.

3.7.2Compliance with the energy efficiency requirements should be demonstrated by showing that satisfactory performance has been achieved against each of the five compliance criteria set out in this Approved Document. However, if more than 70 per cent of the external envelope of the building is to be created from sub-assemblies/modules manufactured prior to the date this Approved Document comes into force, the TER should be adjusted by the relevant factor from Table 2 and it is not necessary to meet the requirement for TPEC. One way of demonstrating the date of manufacture of each sub- assembly/module is by relating the serial number to the manufacturer’s records. If the modules are to be refurbished as part of the process, then the guidance in Approved Document L2B should be followed in terms of the standards to be achieved, e.g. for replacement windows and new lighting.

3.7.3Portable buildings with an intended planned service life in a given location of less than 2 years are often ‘distress purchases’ (e.g. following a fire), and the buildings must be up and operational in a matter of days. In such cases, different arrangements for demonstrating compliance apply. An example of the evidence that the

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planned service life in the given location is less than 2 years would be the hire agreement for the unit.

a.A TPEC/BPEC and a TER/BER calculation should be carried out when the module is first constructed and can be based on a standard generic configuration. This calculation can then be provided as evidence of satisfying the requirements of Criterion 1, whenever the building is moved to a new location, provided its intended service life in that new location is less than 2 years. In addition to the details of the calculation, the supplier should provide written confirmation that:

i.the modules as actually provided meet or exceed the elemental energy standards of the generic module on which the calculation was based; and

ii.the activities assumed in the generic module are reasonably representative of the planned use of the actual module.

b.Where the planned service life in a given location is less than 2 years, the only practical heating technology is electric resistance heating. In such cases, energy efficiency measures should be provided that are 15 per cent better than if using conventional fossil fuel heating. This can be demonstrated by assuming that the heating in the generic configuration used for the TPEC/BPEC and a TER/BER calculation is provided by a gas boiler with an efficiency of 77 per cent.

c.If TER/BER calculations are not available for a module constructed prior to July 2014, reasonable provision would be to demonstrate that the BER is not greater than the 2014 TER adjusted by the relevant factor from Table 2. It is not necessary to meet the TPEC for a module constructed prior to July 2014.

d.Post initial construction, any work on the module should meet the standards set out in Approved Document L2B.

3.8Shell and core developments

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3.8.1If a building is offered to the market for sale or let as a shell for specific fit-out work by the incoming occupier, the developer should demonstrate via the design-stage TPEC/BPEC and TER/BER submission how the building shell as offered could meet the energy efficiency requirements. For those parts of the building where certain systems are not installed at the point the building is to be offered to the market, the model that is used to derive the BPEC and BER should assume efficiencies for those services that will be installed as part of the first fit-out work. The specification provided to the BCB should identify which services have not been provided in the base build, and the efficiency values assumed for each such system. This will enable the BCB to ensure that the necessary infrastructure needed to deliver the assumed fit-out specification is provided as part of the base build. At practical completion of the base building, the as-built TPEC/BPEC and TER/BER calculation should be based only on the building and systems as actually constructed; the fit-out areas should be assumed to be conditioned to temperatures appropriate to their designated use, but no associated energy demand included.

Note: As part of the design-stage calculation, a predicted Energy Performance Certificate (EPC) rating for the fit-out areas should be available to inform prospective occupiers of the energy performance that is achievable. However, a formal EPC lodged on the EPC register is not required at this stage.

3.8.2When an incoming occupier does first fit-out work on all or part of the building through the provision or extension of any of the fixed services for heating, hot water, air- conditioning or mechanical ventilation, then TPEC/BPEC and TER/BER submission should be made to the BCB after completion to demonstrate compliance for the part of the building covered by the fit-out work. This submission should be based on the building shell as constructed and the fixed building services as actually installed. If the fit-out work does not include the provision or extension of any of the fixed services for heating, hot water, air-conditioning or mechanical ventilation, then reasonable provision would be to demonstrate that any lighting systems that are installed are at least as efficient as those assumed in the shell developer’s initial submission.

Note: Since the fit-out is specific to the needs of the particular tenant and is, by definition, uniquely controlled by him for his benefit, this is creating a new ‘part designed or altered for separate use’, and a new EPC is required for that part of the physical building covered by the fit-out.

3.9Buildings with a low energy demand

3.9.1Exemptions from the energy efficiency requirements for industrial sites, workshops and non-residential agricultural buildings with low energy demand are described in Section 9.

3.9.2Where other categories of building with low energy demand is constructed, it would not be reasonable for the building envelope to be insulated to the same standard as for typical new buildings.

3.9.3This applies to buildings or parts thereof where:

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a.fixed building services are used to heat or cool only a localised area rather than the entire enclosed volume of the space concerned (e.g. localised radiant heaters at a workstation in a generally unheated space); or

b.fixed building services are used to heat spaces in the building to temperatures substantially lower than those normally provided for human comfort (e.g. to provide condensation or frost protection in a warehouse).

3.9.4In such situations, no TPEC/BPEC and TER/BER calculations are required. Furthermore, every fixed building service that is installed should meet the energy efficiency standards set out in the Non-Domestic Building Services Compliance Guide4.

3.9.5In addition, if some general heating is provided (case b above), the opaque fabric within the new or renovated building envelope should achieve a U-value no worse than 0.7 W/m².K.

3.9.6If a part of a building with low energy demand is partitioned off and heated normally (e.g. an office area in an unheated warehouse), the separately heated area should be treated as a separate ‘building’ and the normal procedures for demonstrating compliance (including TPEC/BPEC and TER/BER calculation) should be followed in respect of the enclosure.

3.9.7If a building with low energy demand subsequently changes such that the space is generally conditioned, then this is likely to involve the initial provision or an increase in the installed capacity of a fixed building service. The guidance in Approved Document L2B would require the building envelope to be upgraded and a consequential improvement to be made, a process that is likely to be much more expensive than incorporating suitable levels of insulation at the new-build stage. Alternatively, if the building shell was designed as a building with low energy demand and the first occupier of the building wanted to install (e.g.) heating, this would be first fit-out works, and a full TPEC/BPEC and TER/BER submission would then be required (see paragraph 1.3.1).

3.10Industrial sites, workshops and non-residential agricultural buildings other than those with a low energy demand

3.10.1Special considerations may apply in such cases, e.g. where a CO 2 target is established through other regulatory frameworks such as the Carbon Reduction Commitment, or where it is impractical for the generic National Calculation Methodology to adequately account for the particular industrial processes or agricultural use without leading to the possibility of negative impacts on cost-effectiveness and/or increased technical risk. In such cases, reasonable provision would be to provide fixed building services that satisfy the standards set out in Approved Document L2B.

3.10.2Exemptions from the energy efficiency requirements for industrial sites, workshops and non-residential agricultural buildings with low energy demand are described in Section 9.

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3.11.1This Approved Document gives guidance on how to comply with the energy efficiency requirements for the construction of larger extensions to existing non- domestic buildings. These building works are where the total useful floor area of the extension is greater than 100 m² and greater than 25 per cent of the total useful floor area of the existing building.

3.11.2The approach for assessing compliance is similar to that of new non-domestic buildings with the exception that the elemental specifications used to set the TPEC and TER exclude the renewable energy component. This takes into account less design flexibility when constructing an extension to an existing building compared to constructing a new building.

3.12 Demonstrating compliance

3.12.1Before commencement of construction work, the BCB must be notified of the as- designed values of the BPEC/TPEC and BER/TER, thereby confirming that the as- designed building complies with Criterion 1. In addition, the BCB should be given a list of specifications for building fabric, fixed building services and renewable systems (if any) used in calculating the BPEC and BER.

3.12.2It is expected that the approved software will be used to produce, in addition to the design stage BPEC/TPEC and BER/TER, the list of specifications and highlight those ‘key features’ of the design that are critical to achieving compliance (see Section 10 for more details of the ‘key features’ to be identified).). These ‘key features’ may be used to prioritise the risk-based inspection of the building as part of confirming compliance with the Building Regulations.

3.12.3On completion of the building works for a building, the BCB must be notified of the final values of the BPEC/TPEC and BER/TER, thereby confirming that the completed building complies with Criterion 1. Supporting information must also be provided confirming if the construction was in accordance with the specification submitted to the BCB prior to commencement of work and, if not, all changes must be clearly listed. The BCBs are authorised to accept, as evidence of compliance of Criterion 1, a certificate to this effect signed off by a suitably accredited energy assessor.

3.12.4For all specifications, prior to commencement of work and after completion, it would be useful to provide the BCB with additional information to support the values used in the BPEC and BER calculations. For example, U-values might be determined from a specific calculation, in which case the details should be provided, or from an accredited source, in which case a reference to that source would be sufficient.

3.12.5More information on notifying the BCB is given in Section 10.

.

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Requirement

Schedule 1 – Part L Conservation of fuel and power

L1.Reasonable provision shall be made for the conservation of fuel and power in buildings by:

(a) limiting heat gains and losses—

(i) through thermal elements and other parts of the building fabric; and

(ii) from pipes, ducts and vessels used for space heating, space cooling and hot water services;

(b) providing fixed building services which—

(i) are energy efficient;

(ii) have effective controls; and

(iii) are commissioned by testing and adjusting as necessary to ensure they use no more fuel and power than is reasonable in the circumstances.

4.1.1Considerable flexibility is allowed in devising a design and specification strategy to demonstrate compliance with Criterion 1, however the Building Regulations require that provision is made to ensure that:

a.Heat gains and losses through the fabric of the building are limited; and

b.Energy efficient fixed building services with effective controls are provided to all buildings.

4.1.2This requirement can be satisfied by adopting the guidance on the minimum energy efficiency standards for the building fabric and building services and associated controls which are set out in this Section.

Note that, introducing the TPEC limits fabric heat gains and losses and energy consumption from fixed building services. However, achieving the TPEC could be dependent on very good performance of one specific feature of the design with poorer performance elsewhere. If this key element of the design was to fail, or perform less well than expected, this would have a significant impact on performance. Hence minimum energy efficiency standards for building fabric and service elements have been retained.

4.1.3Meeting the standards set in this section of the Approved Documents, for building fabric and fixed services, should be considered a starting point towards achieving the TPEC and TER. It is likely that the design standards will need to be considerably better than the stated values in more than one aspect. The specification in Appendix B provides a better indication of the standards that will be required to meet the TPEC and the TER.

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4.2.1In order to demonstrate compliance with this criterion, the fabric parameters should be as good as or better than the worst acceptable values set out in Table 3.

4.2.2The stated U-values for the main building elements are expressed as area- weighted average value for all types of that element in each building.

4.2.3Approved Document C provides worst acceptable U-values for individual sections comprising each element to minimise the risk of condensation in buildings.

4.2.4U–values should be calculated as given in Appendix C of this Approved Document.

4.3 Fixed building services

4.3.1Guidance on the minimum energy efficiency standards of fixed building services is set out in the Non-Domestic Building Services Compliance Guide5.

4.3.2The energy efficiency of each fixed building service should be as good as or better than that of the worst acceptable value for the particular type of appliance of system as set out in the Non-Domestic Building Services Compliance Guide. If the type of appliance is not covered, then it would be reasonable to demonstrate that the proposed system is no less efficient than a comparable system that is covered by the Non-Domestic Building Services Compliance Guide as agreed with the BCB.

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4.3.3The efficiency claimed for the fixed building service should be based on the appropriate test standard as set out in the Non-Domestic Building Services Compliance Guide, and the test data should be certified by a notified body. It would be reasonable for a BCB to accept such data at face value. In the absence of such quality assured data, the BCB would need to satisfy itself that the claimed performance is justified.

4.3.4Controls should be installed with new HVAC (heating, ventilation and air conditioning) systems to enable the achievement of reasonable standards of energy efficiency. Typically, the following control features would be appropriate and should be included:

a.the fixed building services systems should be sub-divided into separate control zones to correspond to each area of the building that has a significantly different solar exposure, occupancy period or type of use; and

b.each separate control zone should be capable of independent timing and temperature control and, where appropriate, ventilation and air recirculation rate; and

c.the provision of the fixed building service should respond to the requirements of the space that it serves. If both heating and cooling are provided, they should be controlled so they do not operate simultaneously; and

d.central plant serving the zone-based systems should operate only as and when required. The default condition should be off; and

e.in addition to these general control requirements, the systems should meet the specific control requirements and general energy efficiency criteria as set out in the Non-Domestic Building Services Compliance Guide.

4.3.5Energy meters should be installed to allow effective monitoring of the performance of the newly installed fixed building services as follows:

a.the building occupier should be able to assign at least 90% of the estimated annual energy consumption of each fuel to the various end-use categories (heating, lighting etc). Detailed guidance on how this can be achieved is given in CIBSE TM 396; and

b.energy meters should be provided to enable the performance of any renewable energy system provided as part of the building works to be separated monitored; and

c.In buildings with a total useful floor area greater than 1000m 2, the energy metering system should enable automatic meter reading and data collection; and

d.the energy metering provisions should be designed such as to facilitate the benchmarking of energy performance as set out in CIBSE TM 467.

4.3.6Consideration should be given to the provision of centralised switches to allow the facilities manager to switch off appliances when they are not needed (e.g. overnight and at weekends). Where appropriate, these should be automated (with manual override) so that energy savings are maximised.

Note: A centralised switch would be more reliable than depending on each individual occupant to switch off their (e.g.) computer.

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4.4.1It is expected that the approved software tools will be used to produce, in addition to the BPEC/TPEC and BER/TER comparisons, the list of specifications and highlight those features of the design that are critical to achieving compliance. This would include a list of the minimum building fabric and services standards that must be met in order to comply with Criterion 2, alongside the comparable fabric and services specifications for the actual building.

4.4.2The BCBs are authorised to accept, as evidence of compliance with Criterion 2, a certificate to this effect signed off by a suitably accredited energy assessor, both at the stage prior to commencement of work and post-completion.

4.4.3In addition to the list of specifications produced by the approved software tools, supporting information including product specification and data from product manufacturer’s data should be provided. More detail on notifying the BCB is given in Section 10.

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5.1.1In order to comply with the Building Regulations, reasonable provision should be made to limit overheating in new building from solar and other heat gains during the summer months.

5.1.2This section applies to all buildings, irrespective of whether they are air conditioned or not. The intention is to limit solar gains during the summer period to either:

a.reduce the need for air-conditioning; or

b.reduce the installed capacity of any air-conditioning system that is installed.

5.1.3If the criterion set out in this section is satisfied in the context of a naturally ventilated building, this is NOT evidence that the internal environment will be satisfactory, since many factors that are not covered by this compliance assessment procedure will have a bearing on the incidence of overheating (incidental gains, thermal capacity, ventilation provisions, etc.)

Note: Therefore, the developer should work with the design teams to specify what constitutes an acceptable indoor environment in each case, and carry out the necessary design assessments to develop solutions that meet the agreed brief. Some ways of assessing the overheating risk are given in CIBSE TM378 and, for education buildings, in BB1019.

5.1.4For the purposes of Part L compliance, reasonable provision for limiting solar gain through the building fabric would be demonstrated by showing that, for each space in the building that is either occupied or mechanically cooled, the solar gains through the glazing aggregated over the period April to September inclusive are no greater than would occur through one of the following reference glazing systems with a defined total solar energy transmittance (g-value) calculated according to BS EN 42010:

a.For every space that is defined in the NCM database as being side lit, the reference case is an east-facing façade with full-width glazing to a height of 1.0m having a framing factor of 10 per cent and a normal solar energy transmittance (g- value) of 0.68.

b.For every space that is defined in the NCM database as being top lit, and whose average zone height is not greater than 6m, the reference case is a horizontal roof of the same total area that is 10 per cent glazed as viewed from the inside out and having rooflights that have a framing factor of 25 per cent and a normal solar energy transmittance (g-value) of 0.68.

c.For every space that is defined in the NCM database as being top lit, and whose average zone height is greater than 6m, the reference case is a horizontal roof of the same total area that is 20 per cent glazed as viewed from the inside out and

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•having rooflights that have a framing factor of 15 per cent and a normal solar energy transmittance (g-value) of 0.46.

Note: In double-height industrial-type spaces, dirt on the rooflights and internal absorption within the rooflight reduce solar gains. These effects, combined with temperature stratification, will reduce the impact of solar gains in the occupied space and so increased rooflight area may be justified. In such situations, the developer should pay particular attention to the design assessments referred to in paragraph 5.1.4b.

d.For the purpose of this specific guidance, an occupied space means a space that is intended to be occupied by the same person for a substantial part of the day. This excludes circulation spaces, and other areas of transient occupancy, such as toilets, as well as spaces that are not intended for occupation (e.g. display windows).

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6.1.1In order that the intended performance in use of fuel and power is achieved, buildings must be constructed and equipped so that the performance is consistent with the BPEC and BER as calculated at the completion of the building work. In normal circumstances, this would be to demonstrate by evidence that:

a.thermal bypasses are limited (see Section 6.2); and

b.the insulation is reasonably continuous over the whole building envelope to limit thermal bridging (Section 6.3); and

c.the air-permeability is within reasonable limits (Section 6.4); and

d.the fixed building services and their controls are installed and commissioned so that they use no more fuel and power than is reasonable under the circumstances (Section 6.5).

6.2Limiting thermal bypasses

6.2.1Where the layer of insulation is not contiguous with the line defining the air-barrier of a building, there is a possibility that a gap may occur which would be subject to movement of cold air from outside, thereby setting up heat loss through a thermal bypass.

6.2.2A common instance of this would be an uninsulated and unsealed cavity party wall in which heat flowing from adjacent buildings into the cavity may set up air circulation due to stack effect. This would cause the warmed air to rise through the cavity and pull in cool air from the underfloor void.

6.2.3The extent of air flow and heat loss will depend on a number of external conditions such as degree of exposure, wind and temperatures. The air movement and resulting heat losses can be significant.

6.2.4As a general rule, the line of insulation must be contiguous with the air-barrier in buildings, and where this is not possible, the gap in between must be filled with solid material such as in a masonry wall.

6.3Thermal bridging

6.3.1The building fabric should be constructed so that there are no reasonably avoidable thermal bridges. Thermal bridges are instances where heat loss is worse than through the main building fabric. They allow heat to flow between the outer and inner surfaces of a wall, floor and roof by bridging the insulation.

6.3.2Thermal bridges occur in the building fabric:

a.where there are gaps in the continuity of the insulation layer,

b.at the joints between two elements, such as where the external wall meets the ground floor, and

c.at the edges of an element, such as around a window opening.

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6.3.3Ways of demonstrating that reasonable provision has been made in the BPEC and BER calculations are as follows.

a.Use linear thermal transmittance values for construction joint details that have been calculated by a person with suitable expertise and experience following the guidance set out in BR 497 Reasonable provision for temperature factors is that they should achieve a performance no worse than that set out in BRE Information Paper IP 1/0612.. 11 and following a process flow sequence that has been provided to the BCB indicating the way in which the detail should be constructed. These values can then be used in the BPEC and BER calculations.

Evidence of suitable expertise and experience for calculating linear thermal transmittance would be to demonstrate that the person has been trained in the software used to carry out the calculation, has applied that model to the example calculations set out in BR 497 and has achieved results that are within the stated tolerances.

b.To use construction joint unaccredited details, with no specific quantification of the thermal bridge values. In such cases, the generic linear thermal bridge values as given in IP 1/06 increased by 0.04 W/MK or 50 per cent whichever is greater must be used in the BPEC and BER calculations.

6.3.4When using details as determined from paragraph 6.2.3a, the builder should demonstrate to the BCB that an appropriate system of site inspection is in place to give confidence that the construction procedures achieve the required standards of consistency. One way of achieving this would be to produce a report including evidence of site quality control during the construction period of the thermal insulation and air barrier (e.g. photographs, site reports etc).

6.4 Air pressure testing

Regulation 43 - Pressure testing

(1) This regulation applies to the erection of a building in relation to which paragraph L1 (a) (i) of Schedule 1 imposes a requirement.

(2) Where this regulation applies, the person carrying out the work shall, for the purpose of ensuring compliance with regulation 26 and paragraph L1(a)(i) of Schedule 1:

(a) ensure that:

i. pressure testing is carried out in such circumstances as are approved by the

Secretary of State; and ii. the testing is carried out in accordance with a procedure approved by the

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Secretary of State; and

(b) subject to paragraph (5), give notice of the results of the testing to the local authority.

(3) The notice referred to in paragraph (2)(b) shall:

(a) record the results and the data upon which they are based in a manner approved by the Secretary of State; and

(b) be given to the local authority not later than seven days after the final test is carried out.

(4) A local authority is authorised to accept, as evidence that the requirements of paragraph (2)(a)(ii) have been satisfied, a certificate to that effect by a person who is registered by the Independent Airtightness Testing Scheme Limited or the Air Tightness and Testing and Measuring Association in respect of pressure testing for the air tightness of buildings.

(5) Where such a certificate contains the information required by paragraph (3)(a), paragraph (2)(b) does not apply.

6.4.1This section sets out the approved circumstances under which air-pressure testing is to be carried out in order to demonstrate compliance with regulation 43 – pressure testing.

6.4.2The approved procedure for pressure testing of the building envelope of the building, and recording the results and the underpinning data, is given in the ATTMA publication Measuring air permeability of building envelopes13. The preferred test method is that trickle ventilators should be temporarily sealed rather than just closed.

6.4.3BCBs should be provided with evidence that test equipment has been calibrated within the previous 12 months using a UKAS-accredited facility and that the person has received appropriate training and is registered to test the specific class of building concerned.

6.4.4All non-domestic buildings (including extensions which are being treated as new buildings for the purposes of complying with Part L) should be pressure tested, with the following exceptions;

a.Buildings less than 500 m 2 total useful floor area; in this case the developer may choose to avoid the need for a pressure test provided that the air permeability used in the calculation of the BPEC and BER is taken as 15 m 3/(h.m2) at 50 Pa.

Compensating improvements in other elements of the building fabric and building services will be needed to keep the BPEC and BER no worse than the TPEC and TER.

b.A factory-made modular building of less than 500 m 2 floor area, with a planned service life of more than 2 years at more than one location, and where no site

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•assembly work is needed other than making linkages between standard modules using standard link details. Compliance can be demonstrated by giving a notice to the BCB confirming that the building as installed conforms to one of the standard configurations of modules and link details for which the installer has pressure test data from a minimum of five in-situ measurements incorporating the same module types and link details as utilised in the actual building. The results must indicate that the average test result is better than the design air permeability as specified in the BPEC and BER calculation by not less than 1.0 m 3/(h.m 2) at 50 Pa.

c.Large extensions (whose compliance with Part L is being assessed as if they were new buildings – see Approved Document L2B) where sealing off the extension from the existing building is impractical. The ATTMA publication gives guidance both on how extensions can be tested and on situations where pressure tests are inappropriate. Where it is agreed with the BCB that testing is impractical, the extension should be treated as a large, complex building, with the guidance in (d) below being applicable.

d.Large complex buildings, where due to building size or complexity it may be impractical to carry out pressure testing of the whole building. The ATTMA publication indicates those situations where such considerations might apply. Before adopting this approach developers must produce (in advance of construction work in accordance with the approved procedure) a detailed justification of why pressure testing is impractical. This should be endorsed by a suitably qualified person such as a competent person approved for pressure testing. In such cases, a way of showing compliance would be to appoint a suitably qualified person to undertake a detailed programme of design development, component testing and site supervision to give confidence that a continuous air barrier will be achieved. It would not be reasonable to claim an air permeability better than 5.0 m³/ (h.m²) at 50 Pa has been achieved

One example of a suitably qualified person would be an ATTMA member. The 5.0 m³/ (h.m²) at 50 Pa limit has been set because at better standards, the actual level of performance becomes too vulnerable to single point defects in the air barrier.

e.Compartmentalised buildings, where buildings are compartmentalised into self- contained units with no internal connections it may be impractical to carry out whole building pressure tests. In such cases reasonable provision would be to carry out a pressure test on a representative area of the building as detailed in the ATTMA guidance. In the event of a test failure, the provisions of 6.3.5 to 6.3.7 would apply, but it would be reasonable to carry out a further text on another representative area to confirm that the expected standard is achieved in all parts of the building.

6.4.5Compliance would be demonstrated if:

a.the measured air permeability is not worse than the limiting value of 10 m³/(h.m²) at 50 Pa; and

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b.the BPEC and BER calculated using the measured air permeability is not worse than the TPEC and TER.

6.4.6If satisfactory performance is not achieved, then the remedial measures should be carried out on the building and new test carried out until the building achieves the criteria set out in paragraph 6.3.5.

6.4.7If the measured air permeability on retest is greater than the design air permeability but less than the limiting value of 10 m³/(h.m²) at 50 Pa then other compensating improvements may be undertaken to the building fabric and services to achieve the TPEC and TER.

Note: Builders may therefore wish to schedule air pressure tests early enough to facilitate compensating improvements on the building fabric if necessary e.g. before false ceilings are up.

6.5 Commissioning of building services

Regulation 44 - Commissioning

(1) This regulation applies to building work in relation to which paragraph F1(2) of Schedule 1 imposes a requirement, but does not apply to the provision or extension of any fixed system for mechanical ventilation or any associated controls where testing and adjustment is not possible.

(2) This regulation applies to building work in relation to which paragraph L1(b) of Schedule 1 imposes a requirement, but does not apply to the provision or extension of any fixed building service where testing and adjustment is not possible or would not affect the energy efficiency of that fixed building service.

(3) Where this regulation applies the person carrying out the work shall, for the purpose of ensuring compliance with paragraph F1(2) or L1(b) of Schedule 1, give to the local authority a notice confirming that the fixed building services have been commissioned in accordance with a procedure approved by the Secretary of State.

(4) The notice shall be given to the local authority–

(a) not later than the date on which the notice required by regulation 16(4) is required to be given; or

(b) where that regulation does not apply, not more than 30 days after completion of the work.

Where the BCB is an Approved Inspector see regulation 20 of the Building (Approved Inspector etc.) Regulations 2010

6.5.1.The Building Regulations require the commissioning of fixed building services by testing and adjustment as necessary to ensure that they are handed over in efficient working order. This includes both the systems and associated controls.

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6.5.2.This regulation does not apply to fixed building services where testing and adjustment is not possible, for instance where the only controls are ‘on’ and ‘off’ switches. Examples of this would be some mechanical extraction systems or single fixed electrical heaters. The regulation also does not apply to commissioning of fixed building services which would have no effect on energy use.

6.5.3.A commissioning plan should be prepared in advance, identifying the systems that need to be tested and the tests that will be carried out, and provided with the design stage BPEC/TPEC and BER/TER calculation so that the BCB can check the commissioning is being done as the work proceeds. This plan should also identify the fixed building services which do not require commissioning, along with the reason for not requiring commissioning.

6.5.4.Where commissioning is carried out, it must be done in accordance with the following procedure approved by the Welsh Ministers:

a.CIBSE Commissioning Code M: Commissioning management This provides details on the overall process as well as a schedule of the relevant documents relating to the commissioning of specific building services systems 14.

b.for leakage testing of ductwork, paragraphs 6.4.8 to 6.4.10.

6.5.5Commissioning should be carried out in such a way as not to prejudice compliance with any applicable health and safety requirements.

Energy efficiency in practice can often be enhanced by a sustained period of fine tuning to ensure the systems are operating as intended and controls are configured to the needs of the occupier. The Soft Landings initiative is an example of an appropriate fine tuning process (see http://www.bsria.co.uk/services/design/soft-landings/).

6.5.6Membership of the Commissioning Specialists Association or the Commissioning group of the B&ES are possible ways of demonstrating suitability to sign the commissioning report in respect of the HVAC systems. For lighting control systems, suitability may be demonstrated by accreditation under the Lighting Industry Commissioning Scheme. A way of documenting the process would be the use of the templates in the Model Commissioning Plan (BSRIA BG 8/2009).

6.5.7Notice of commissioning of any fixed building services should be given to the BCB within five working days of the completion of the commissioning work (or within thirty days if the work is carried out by a person registered with a competent person scheme). The notice should include confirmation that the commissioning plan has been followed and that the test results show performance in accordance with the design requirements (including written commentary where any differences are proposed to be accepted by the BCB). Until the Building Control Body receives the commissioning

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notice it cannot be reasonably satisfied that Part L has been complied with and consequently is unlikely to be able to provide a certificate of compliance.

6.5.8Ductwork leakage testing should be carried out where required by and in accordance with the procedures set out in B&ES DW/143 and B&ES DW/144 on systems served by fans with a design flow rate greater than 1 m 3/s.

NOTE: DW/143 does not call for any testing of low-pressure (class A) ductwork. However, where at least 10% of low-pressure ductwork is tested at random and achieves the low-pressure standard as defined by DW/143 the NCM recognises an improvement in the BPEC and BER. A decision to test low-pressure ductwork should be made at the initial design phase prior to commencement on site. The ductwork pressure classes are set out in Table 4.

1Where ∆P is the differential pressure in Pascals

6.5.9If a ductwork system fails to meet the leakage standard, remedial work should be carried out as necessary to achieve satisfactory performance in retests and further ductwork sections should be tested as set out in DW/143.

6.5.10Membership of the B&ES specialist ductwork group or the Association of Ductwork Contractors and Allied Services (ADCAS) could be a way of demonstrating suitable qualifications for testing work

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Regulation 40 – Information about use of fuel and power

(1) This regulation applies where paragraph L1 of Schedule 1 imposes a requirement relating to building work

(2) The person carrying out the building work shall not later than 5 days after the work has been completed provide the owner with sufficient information about the building, fixed building services and their maintenance requirements so that the building can be operated in such a manner as to use no more fuel and power than is reasonable in the circumstances.

7.1.1In accordance with regulation 40 the owner of the building should be provided with sufficient information about the building, the fixed building services and their maintenance requirements so that the building can be operated in such a manner as to use no more fuel and power than is reasonable in the circumstances.

7.2 Building Log Book

7.2.1The necessary information should be provided by following the guidance in CIBSE TM 31 Building log book toolkit. An alternative guidance document can be followed in preparing the log book, if the information conveyed and the format of presentation is equivalent to TM 3115.

7.2.2The information should be presented in templates as or similar to those in TM 31. The information should be provided in summary form, suitable for day-to-day use. It could draw on or refer to information available as part of other documentation, such as the Operation and Maintenance Manuals and the Health and Safety file required by the CDM Regulations. Further advice is provided in BSRIA BG26/2011 Building Manuals and Building User Guides16.

7.2.3The data used to calculate the BPEC, TPEC, BER and TER should be included with the log book. The occupier should also be provided with the recommendations report, generated in parallel with the “on-construction” Energy Performance Certificate, which will inform the occupier as to how the energy performance of the building might be further improved.

It would also be sensible to retain an electronic copy of the input file for the BPEC/TPEC and BER/TER calculation to facilitate any future analysis that may be required by the owner when altering or improving the building.

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Regulation 24 - Methodology of calculation of the energy performance of buildings

(1) The Secretary of State shall approve–

(a) a methodology of calculation of the energy performance of buildings, including methods for calculating asset ratings and operational ratings of buildings; and

(b) ways in which the energy performance of buildings, as calculated in accordance with the methodology, shall be expressed.

(2) In this regulation–

‘asset rating’ means a an energy performance indicator determined from of the amount of energy estimated to meet the different needs associated with a standardised use of the building; and

‘operational rating’ means an energy performance indicator determined from the amount of energy consumed during the occupation of a building over a period of time and the energy demand associated with a typical use of the building over that period.

Regulation 25 - Minimum energy performance requirements for buildings

The Secretary of State shall approve minimum energy performance requirements for new buildings, in the form of target CO2 emission rates, which shall be calculated and expressed in accordance with the methodology approved pursuant to regulation 24.

Regulation 25C(a) – New Buildings – minimum energy performance requirements

Minimum energy performance requirements must be approved by the Welsh Ministers, calculated and expressed in accordance with the methodology approved pursuant to regulation 24 for- new buildings (other than new dwellings), in the form of target primary energy consumption rates.

8.1.1The Target Primary Energy Consumption (TPEC) and the Target CO 2 Emission Rate (TER) are the minimum energy performance requirements for a new building approved by the Welsh Ministers in accordance with the regulation 25C(a) and regulation 25.

8.1.2In accordance with the methodology approved by the Welsh Ministers in the Notice of Approval17, the TPEC and TER for individual builders must be calculated using one of the following approved software tools:

a.The Simplified Building Energy Model (SBEM)18 for those buildings whose design features are capable of being adequately modeled by SBEM; or

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b.Other approved software tools which can be found on the Departments website at www.communities.gov.uk.

8.1.3As part of the submission to a BCB, the applicant must show that the software tool used is appropriate to the application.

8.1.4The TPEC is calculated by determining the primary energy consumption from a building of the same size and shape as the actual building and which is constructed according to the elemental specification set out in the 2013 Wales NCM Modelling Guide19 using one of the approved software tools. Key components of this specification can also be seen in Appendix B of this Approved Document with the exception that all electrical demand is assumed to be supplied from the grid (i.e. energy generated by the PV system is disregarded) so that the TPEC is based only on the fabric and building services performance.

8.1.5The TER is calculated by determining the CO 2 emissions from a building of the same size and shape as the actual building and which is constructed according to the elemental specification set out in the 2013 Wales NCM Modelling Guide using one of the approved software tools. Key components of this specification can also be seen in Appendix B of this Approved Document.

This update to the Approved Document maintains the approach to setting the TER adopted in 2010 whereby the TER is based on an elemental set of specifications to which no additional improvement factor is applied The specifications now include an area of roof mounted photovoltaic panels.

8.2 Conservatories and porches

8.2.1Conservatories and porches should be included in the TPEC and TER calculations only if they are constructed at the same time as a new building; and

a.There is no thermal element between the building and the conservatory and/or porch; or

b.The conservatory and/or porch will be heated via fixed heating.

8.3 Swimming pools

8.3.1Where a swimming pool is constructed as part of a new building, the building should be assessed as if the pool basin was not present, while the pool hall should be included in the calculation of the TPEC and TER.

8.3.2The area covered by the pool basin should be taken into account in the calculation, as an equivalent area of floor.

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9.1.1The energy efficiency requirements apply to buildings or parts of buildings that are walled and roofed constructions and use energy to heat or cool the indoor climate. Parts of a building which are not heated or cooled, for example carports, covered ways and some conservatories or entrance halls, are exempt. Guidance on which conservatories and porches are exempt is given in this section. Some buildings with special characteristics are also exempt with guidance provided in this section.

9.2 Places of worship9.2.1 Places of worship are exempt from the energy efficiency requirements.

9.2.2Places of worship, for the purposes of the energy efficiency requirements, are taken to mean those buildings or parts thereof that are used for formal public worship, including adjoining spaces whose function is directly linked to that use (for example, a vestry in a church). Such buildings often have traditional, religious or cultural constraints that mean compliance with the energy efficiency requirements is not possible.

9.2.3Other parts of the building that are designed to be used separately, such as offices, catering facilities, day centres, meeting halls and accommodation are not exempt.

9.3 Temporary buildings

9.3.1Temporary buildings with a planned time of use of two years or less are exempt from the energy efficiency requirements.

9.3.2This does not include modular and portable buildings which have a planned service life greater than 2 years, whether located on one or more sites.

9.4 Industrial sites, workshops and non residential agricultural buildings with a low energy demand

9.4.1Industrial sites, workshops and non residential agricultural buildings with low energy demand are exempt from the energy efficiency requirements. The low energy demand relates only to the energy used by fixed heating or cooling systems and not to energy required for or created by process needs.

9.4.2Examples of such buildings that are low energy demand are as follows:

a.buildings or parts of buildings where the space is not generally heated, other than by process heat, or cooled;

b.buildings or parts of buildings that require heating or cooling only for short periods each year, such as during critical periods in the production cycle (e.g. plant germination, egg hatching) or in very severe weather conditions.

9.4.3Other buildings (e.g. some types of warehouse) may have low energy demand but are not exempt because they do not fall into one of the above categories of buildings (i.e.

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industrial sites, workshops or non-residential agricultural buildings). See section 3.9 for more detail.

9.5 Conservatories and porches

9.5.1Conservatory and porches installed at the same time as the new building are exempt from the energy efficiency requirements if they meet the following conditions:

a.they are located at ground level;

b.the floor area is less than 30m 2

c.the existing walls, doors and windows which separate the conservatory from the building are retained or, if removed, are replaced by walls, windows and doors which meet the energy efficiency requirements; and

d.contains no fixed heating appliance or extension of the buildings heating system.

9.5.2Guidance for non-exempt conservatory and porches is given in section 8.2.

9.6 Stand-alone buildings

9.6.1Building work is also exempt from the energy efficiency requirements on stand- alone buildings other than dwellings with a total useful floor area of less than 50m 2.

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10.1.1In all cases where it is proposed to erect a new building, Building Regulations require the person proposing to carry out the work to notify a BCB, either the local authority or an approved inspector, in advance of any work starting. This notification would usually be by way of full plans (or possibly a building notice) given to a local authority, or an initial notice given jointly with the approved inspector. However, some elements of the work may not need to be notified to a BCB in advance as set out in Section 10.2.

10.1.2Sections 3 to 7 detail the evidence to demonstrate compliance with the energy efficiency requirements both at the design and completed stages of construction. To facilitate effective communication between the person undertaking the work and BCB, it would be beneficial to adopt a standardised report format for presenting the evidence that demonstrates compliance with the energy efficiency requirements.

10.1.3Since the data in the approved compliance software and the results calculated can provide a substantial proportion of the evidence in support of the compliance demonstration, it is anticipated that approved software will produce this report as a standard output option.

10.1.4It is anticipated that two versions of the standardised report would be produced by the approved compliance software: the first before commencement of works to include the as-designed calculations plus supporting list of specifications and the second after completion to include the as built calculations plus any changes to the list of specifications. The first design-stage report and accompanying list of specifications can then be used by the BCB to assist checking that what has been designed is actually built. A standardised report should enable the source of the evidence to be indicated, and allow the credentials of those submitting the evidence to be declared.

10.1.5An important part of demonstrating compliance is to make a clear the information, product specifications and the data inputs referred to for input into the compliance software (e.g. the wall construction that would deliver the claimed U-value). Examples as to how compliance software might provide this link are:

a.By giving each data input a reference code that can be mapped against a separate submission by the applicant/developer that details the specification corresponding to each unique reference code in the data input.

b.By providing a free-text entry facility along with each input parameter that has a unique reference code, thereby allowing the software to capture the specification of each item and so include the full details in an integrated output report.

c.By including one or more utility programs that derive the data input from the specification, e.g. a U-value calculator that conforms to BR 44320 and that calculates the U-value based on the layer thicknesses and conductivities, repeating thermal bridge effects etc. Outputs from such a utility program could then automatically generate the type of integrated report described at b. above.

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10.1.6The report should indicate the percentage by which the average performance of elements in the actual building deviates from the elemental specifications in the notional buildings (see Appendix B). The BCB is advised to give particular attention to elements that are more than 10% better that the elemental specification as their appropriate installation will be critical in achieving the TPEC and the TER.

10.1.7It is expected that low and zero carbon technologies will be increasingly employed for compliance with the TER, particularly where the average performance of elements in the actual building is worse than the elemental specification. The report should highlight where these low and zero carbon technologies have been used and the BCB is advised to give particular attention to their installation.

10.2 Cases when notification is not needed – Competent person scheme

10.2.1Some elements of the work may not need to be notified to a BCB, in advance, if carried out by someone registered with a relevant Competent Person Self-certification scheme. In order to join such a scheme a person must demonstrate competence to carry out the type of work the scheme covers, and also the ability to comply with all relevant requirements in the Building Regulations. A list of these and the types of work for which they are authorised can be found at www.wales.gov.uk/topics/planning/buildingregs/competent-persons-scheme

10.2.2 There are no competent person schemes that cover all aspects of the construction of a new building. There are, however, schemes that cover the electrical and plumbing installation work and the installation of certain fixed building services (heating, hot water, air-conditioning, mechanical ventilation).

10.2.3Where work is carried out by a person registered with a competent person scheme, the occupier of the building and the BCB are required to be given, within 30 days of the completion of the work, a certificate confirming that the work complies fully with all applicable building regulation requirements. These certificates and notices are usually made available through the scheme operator.

10.2.4BCBs are authorised to accept these certificates and notices as evidence of compliance with the requirements of the Building Regulations. Local authority inspection and enforcement powers remain unaffected, although they are normally used only in response to a complaint that work does not comply.

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1.Introduction

Words within this Approved Document which are in bold italics have a definition listed in this section. The following are key terms used in this document:

Air permeability is the physical property used to express airtightness of the building fabric. It is defined as air leakage rate per hour per square metre of envelope area at a test reference pressure differential across the building envelope of 50 Pascal (50 N/m²). The envelope area of the building, or measured part of the building, is the total area of all floors, walls and ceilings bordering the internal volume subject to the test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings. The limiting air permeability is the worst allowable air permeability. The design air permeability is the target value set at the design stage, and must always be no worse than the limiting value. The assessed air permeability is the value used in established the BER, and is based on a specific measurement of the building concerned.

BCB means Building Control Body: a local authority or an approved inspector.

BER is the Building Carbon Dioxide (CO 2) Emission Rate. It is expressed in terms of the mass of CO 2, in units of kg per m2 of the total useful floor area of the building per year, kgCO 2/(m 2.year), emitted as a result of the provision of the specified fixed building services, which include space and water heating, ventilation system and fixed lighting systems, for a standardised occupancy when assessed using approved calculation tools.

BPEC is the Building Primary Energy Consumption. It is expressed in terms of the amount of primary energy consumed in the building, in units of kWh per m 2 of the total useful floor area of the building per year, kWh/(m 2.year), as a result of the provision of the specified fixed building services, which include space and water heating, ventilation system and fixed lighting systems, for a standardised occupancy when assessed using approved calculation tools.

Building means the whole of a building or parts of it designed or altered to be used separately.

Commissioning means the advancement of a fixed building service following the installation, replacement, extension or alteration of the whole or part of the system, from the state of static completion to working order by testing and adjusting as necessary to ensure that the system as a whole uses no more fuel and power than is reasonable in the circumstances, without prejudice to the need to comply with health and safety requirements. For each system commissioning includes setting-to-work, regulation (that is testing and adjusting repetitively) to achieve the specified performance, the calibration, setting up and testing of the associated automatic control systems, and recording of the system settings and the performance test results that have been accepted as satisfactory.

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Delivered energy means energy supplied to the building and its systems to satisfy the relevant energy demands e.g. space heating, water heating, cooling, ventilation, lighting. Delivered energy includes renewable energy produced on site and used within the building but does not include any exported energy.

Display Window means an area of glazing, including glazed doors, intended for the display of products or services on offer within the building, positioned:

a.at the external perimeter of the building; and

b.at an access level and immediately adjacent to a pedestrian thoroughfare.

There should be no permanent workspace within one glazing height of the perimeter. Glazing more than 3m above such an access level should not be considered part of a display window except:

a.where the products on display require a greater height of glazing;

b.in existing buildings, where replacing display windows that already extend to a greater height;

c.in cases of building work involving changes to the façade and glazing requiring planning consent, where planners should have discretion to require a greater height of glazing, e.g. to fit in with surrounding buildings or to match the character of the existing façade.

It is expected that display windows will be found in Planning Use Classes A2, A2, A3 and D2 as detailed in Table 5.

Dwelling refers to a self-contained unit (including a house or a flat) designed to be used separately to accommodate a single household. New Dwellings are covered by Approved Document L1A.

Emergency escape lighting means that part of emergency lighting that provides illumination for the safety of people leaving an area or attempting to terminate a dangerous process before leaving an area.

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Energy efficiency requirements are the requirements of the Building Regulations covered by this Approved Document. See Appendix B for further details of these requirements.

Energy performance certificate means a certificate which complies with Regulation 7A of the Energy Performance of Buildings (England and Wales) Regulations 2012 (SI 2012/3119).

Fit-out work means that work needed to complete the internal layout and servicing of the building shell to meet the specific needs of an incoming occupier. The building shell is the structural and non-structural envelope of a building provided as a primary stage (usually for a speculative developer) for a subsequent project to fit out with internal accommodation works.

Fixed building services means any part of, or any controls associated with—

(a) fixed internal or external lighting systems (but not including emergency escape lighting or specialist process lighting);

(b) fixed systems for heating, hot water, air conditioning or mechanical ventilation; or

(c) any combination of systems of the kinds referred to in paragraph (a) or (b).

Low and Zero Carbon Technologies (LZCs) means technologies that produce renewable non-fossil fuel energy and fossil-fuel technologies that are capable of supplying low carbon energy such as combined heat and power and heat pumps.

National Calculation Methodology (NCM) is the procedure for calculating the energy performance of non-domestic buildings for Part L. Only software tools approved by the Notice of Approval21 (SBEM, approved software interfaces to SBEM or approved Dynamic Simulation Models) should be used.

Non-domestic buildings are those buildings that are not dwellings.

Occupied space is that intended to be occupied by the same person for a substantial part of the day. This excludes circulation spaces, and other areas of transient occupancy, such as toilets, as well as spaces that are not intended for occupation (e.g. display windows).

Primary energy means energy that has not been subjected to any conversion or transformation process. For a building, it is the delivered energy plus the energy used to produce the energy delivered to the building. It is calculated from the delivered energy using primary energy (conversion) factors.

Renewable energy means energy from renewable non-fossil energy sources e.g. solar energy (thermal and photovoltaic), wind, hydropower, biomass, geothermal, wave, tidal, landfill gas, sewage treatment plant gas and biogases. For the purposes of calculating

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the actual building’s primary energy consumption all electricity demand will be valued at the grid primary energy factor, regardless of whether some or all of the delivered electricity is derived from renewable sources on site. This is because the TPEC/BPEC calculation is primarily a measure of the energy efficiency of fabric and building services.

TER is the Target Carbon Dioxide (CO 2) Emission Rate. It is expressed in terms of the mass of CO 2, in units of kg per m2 of the total useful floor area of the building per year, kgCO 2/(m 2.year), emitted as a result of the provision of standardised fixed building services, which include space and water heating, ventilation system and fixed lighting systems, for a standardised occupancy when assessed using approved calculation tools.

Thermal element is used in the Building Regulations to describe a wall, floor or roof, which separates a heated or cooled space from the external environment, the ground, and any parts of the building which are not heated or cooled or, where another part of the building which is not a dwelling, is heated or cooled to a different temperature.

Total useful floor area is the total area of all enclosed spaces measured to the internal face of the external walls, that is to say it is the gross floor area as measured in accordance with the guidance issued to surveyors by the RICS. In this convention:

a.the area of sloping surfaces such as staircases, galleries, raked auditoria and tiered terraces should be taken as their area on plan; and

b.areas that are not enclosed such as open floors, covered ways and balconies are excluded.

TPEC is the Target Primary Energy Consumption. It is expressed in terms of the amount of primary energy consumed in the building, in units of kWh per m 2 of the total useful floor area of the building per year, kWh/(m 2.year), as a result of the provision of the standardised fixed building services, which include space and water heating, ventilation system and fixed lighting systems, for a standardised occupancy when assessed using approved calculation tools

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1.The elemental specifications which must be used to calculate the TPEC and TER of a new building are given in the NCM Modelling Guide22. A summary is given in the table below for different categories of building.

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Note 1: Mixed mode assumed to be cooled by DX unit where SSEER includes indoor and outdoor unit and fans, pumps and losses

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1U-values for thermal elements (walls, floors and roofs) shall be calculated using methods and conventions set out in BRE Report BR 443 Conventions for U-value Calculations, 2006 Edition.

2U-values for windows and doors shall be calculated for the whole unit, i.e. for the combined performance of the glazing or door leaf and the frame, using methods and conventions set out in BRE Report BR 443 Conventions for U-value Calculations, 2006 Edition.

3In the case of a window, the U-value can be calculated for:

a.the standard window set out in BRE Report BR 443 Conventions for U-value Calculations, 2006 Edition;

b.the smaller of the two standard windows set out in BS EN 14351-1 [2006 (+AMD 1:2010)] Windows and doors – Product standard, performance characteristics; or

c.the specific size and configuration of the window.

4In the case of a door, the U-value can be calculated for:

a.the standard door set out in BS EN 14351-1 [2006 (+AMD 1:2010)] Windows and doors – Product standard, performance characteristics; or

b.the specific size and configuration of the door.

5The U-values for roof windows and rooflights set out in Table 3 are calculated for windows positioned in a vertical plane. If a particular unit is not positioned vertically, the U-values to be achieved or bettered set out in this table should be adjusted for the specific angle following the guidance set out in BRE Report BR 443 Conventions for U- value Calculations,2006 Edition.

6The U-values for out-of-plane rooflights (i.e. rooflights that sit proud of the plane of the roof, mounted on upstands or kerbs) should be based on the developed area of the glazing, rather than the aperture area. Details of how the developed area is defined and calculated are given in Assessment of thermal performance of out-of-plane rooflights, NARM Technical Document NTD 2 (2010).

7U-values for indoor swimming pool basins shall be calculated using the methods and conventions set out in BS EN ISO 13370 [2007 incorporating corrigendum March 2009] Thermal Performance of Buildings. Heat transfer via the ground. Calculation methods.

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1.Building work should be carried out in accordance with Regulation 7 of the Building Regulations. Guidance on meeting these requirements on materials and workmanship is contained in the Approved Document to Regulation 7.

2.Building regulations are made for specific purposes, including the health and safety, welfare and convenience of people and for energy conservation. Standards and other technical specifications may provide relevant guidance to the extent that they relate to these considerations. However, they may also address other aspects of performance such as serviceability, or aspects which, although they relate to health and safety, are not covered by the Regulations.

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1.The Workplace (Health, Safety and Welfare) Regulations 1992, as amended, apply to the common parts of flats and similar buildings if people such as cleaners, wardens and caretakers are employed to work in these common parts. These Regulations contain some requirements which affect building design. The main requirements are now covered by the Building Regulations, but for further information see Workplace health, safety and welfare, Workplace (Health, Safety and Welfare) Regulations 1992, Approved Code of Practice and guidance, HSE publication L24, 2 nd Edition, 2013.

2.Where the requirements of the Building Regulations that are covered by this Approved Document do not apply to dwellings, the provisions may still be required in the situations described above in order to satisfy the Workplace Regulations.

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1.The following documents have been approved and issued by Welsh Ministers for the purpose of providing practical guidance with respect to the requirements of the Building Regulations 2010 (2010/2214) for Wales.

Approved Document A

Structure

Approved Document B: Fire Safety

Volume 1: Dwellinghouses

Approved Document B: Fire Safety

Volume 2: Buildings other than dwellinghouses

Approved Document C

Site preparation and resistance to contaminants and moisture

Approved Document D

Toxic substances

Approved Document E

Resistance to the passage of sound

Approved Document F

Ventilation

Approved Document G

Sanitation, hot water safety and water efficiency

Approved Document H

Drainage and waste disposal

Approved Document J

Combustion appliances and fuel storage systems

Approved Document K

Protection from falling, collision and impact

Approved Document L1A

Conservation of fuel and power (New dwellings)

Approved Document L1B

Conservation of fuel and power (Existing dwellings)

Approved Document L2A

Conservation of fuel and power (New buildings other than dwellings)

Approved Document L2B

Conservation of fuel and power (Existing buildings other than dwellings)

Approved Document M

Access to and use of buildings

Approved Document N

Glazing Safety

Approved Document P

Electrical safety – Dwellings

Approved Document 7

Materials and workmanship

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Air Tightness Testing and Measurement Association (ATTMA) www.attma.org

Measuring air permeability of building envelopes (non-dwellings), Technical Standard L2, 2010.

BRE www.bre.co.uk

BR 443 Conventions for U-value calculations, 2006. (Downloadable from www.bre.co.uk/uvalues )

Information Paper IP1/06 Assessing the effects of thermal bridging at junctions and around openings in the external elements of buildings, 2006. ISBN 978 1 86081 904 9

BRE Report BR 497 Conventions for Calculating Linear Thermal Transmittance and Temperature Factors, [2007 and 2010 amendments and conventions]. ISBN 978 1 86081 986 5

National Calculation Methodology (NCM) modelling guide (for buildings other than dwellings in Wales) [2014]. www.wales.gov.uk/topics/planning/buildingregs (to be updated)

Simplified Building Energy Model (SBEM) User manual and software: www.2013ncm.bre.co.uk (to be updated)

BSRIA www.bsria.co.uk

BSRIA BG 8/2009 Model Commissioning Plan

Building and Engineering Services Association (B&ES) www.b-es.org

DW/143 A Practical Guide to Ductwork Leakage Testing [2013].

DW/144 Specification for Sheet Metal Ductwork [2013]

CIBSE www.cibse.org

Commissioning Code M: Commissioning management, 2003. ISBN 978 1 10328 733 0

TM 31 Building Log Book Toolkit, 2006. ISBN 978 1 90328 771 2

TM 37 Design for improved solar shading control, 2006. ISBN 978 1 90328 757 6

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TM 39 Building energy metering, 2009. ISBN 978 1 90684 611 4

TM 46 Energy benchmarks, 2008.

Department for Education (DfE) England www.education.gov.uk

Ventilation of school buildings, Building bulletin 101, School Building and Design Unit, Version 1.4 – 5th July 2006 ISBN 011-2711642

Department for Energy and Climate Change (DECC) www.gov.uk/government/organisations/department-of-energy-climate-change

The Government’s Standard Assessment Procedure for energy rating of dwellings, SAP 2012 (available at www.bre.co.uk/sap2012)

Department for Communities and Local Government www.gov.uk/government/organisations/department-for-communities-and-local- government

Non-Domestic Building Services Compliance Guide, 2013.

Health and Safety Executive (HSE) www.hse.gov.uk

L24Workplace Health, Safety and Welfare: Workplace (Health, Safety and Welfare) Regulations 1992, Approved Code of Practice and Guidance, The Health and Safety Commission, 2 nd edition 2013. ISBN 978 0 71760 413 5

National Association of Rooflight Manufacturers www.narm.org.uk

NARM Technical Document NTD 2 (2010),

Welsh Government www.wales.gov.uk/topics/planning/buildingregs

Notice of approval of the methodology of calculation of the energy performance of buildings in Wales www.planningportal.gov.uk/buildingregulations/approveddocuments/partl/bcassociateddo cuments9/ncm

Source page 57

Legislation

Building Regulations 2010 (SI 2010/2214)

Building (Approved Inspectors etc.) Regulations 2010 (SI 2010/2215)

Building Regulations &c. (Amendment) (Wales) Regulations (SI 2013/747)

The Energy Performance of Buildings (England and Wales) Regulations 2012 (SI 2012/3119).

Standards

BS EN ISO 13370 Thermal performance of buildings. Heat transfer via the ground. Calculation methods [2007 incorporating corrigendum March 2009].

BS EN 410:2011 Glass in building. Determination of luminous and solar characteristics of glazing.

BS EN 14351-1 Windows and doors. Product standard, performance characteristics. Windows and external pedestrian doorsets without resistance to fire and/or smoke leakage characteristics [2006 (+AMD 1:2010)].

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