Building Scotland (Amendment) Regulations 2022 - energy: presentation
- Local Government and Housing Directorate
- Part of
- Building, planning and design
Text version of a presentation on energy standard changes from February 2023 in the Building Scotland (Amendment) Regulations 2022.
This document is part of a collection
An update on the latest 2022/23 changes to building regulations
Energy standards from 1 February 2023
Provisions within The Building Scotland (Amendment) Regulations 2022 on energy performance will come into force on 1 February 2023. The regulations were laid on 22 April 2022 and their in-force date subsequently amended on 17 June 2022 and 17 November 2022. This was in recognition of current delays in delivery of calculation tools elsewhere in the UK.
Changes to the regulations, standards and supporting guidance within section 6 (energy) were published in revised Technical Handbooks on 15 June 2022 and subsequently reformatted with minor amendments on 23 February 2023.
There are also changes within section 3 (environment) on ventilation and overheating (separate presentation available) and a consequential update to Aspect 2 (carbon dioxide emissions) within standard 7.1 (covered in this presentation).
Changes to energy standards for new buildings are supported by the adoption of the new version of SAP (version 10) and of SBEM (v6). This presentation also covers key changes to the UK Methodology and development and issue of calculation tools.
- 2021 Programme for Government: “We will also review energy standards within current building regulations to deliver further improvement in energy efficiency and emissions reductions in new buildings, helping make homes more affordable to heat and tackling fuel poverty”.
- 1990 to 2015: 75-80% reduction in carbon emissions for new build – but it is now not ‘how far we have gone’ but ‘what more we can now do’.
- consultation on Energy Standards ran from July to November 2021.
- 176 responses received. These and consultation analysis published online at: https://consult.gov.scot/local-government-and-communities/building-regulations-energy-standards-review/.
Key changes for February 2023
- adoption of the revised UK calculation methodologies, SAP 10 and SBEM (v6).
- review focussed on building-level actions, which are effective in reducing delivered energy as part of addressing broader issues of overall building performance.
- three notional buildings, separate treatment of space & water heating.
- aggregate emissions improvement to new homes of 32% and new non-domestic buildings of 20%.
- new (additional) delivered energy target for new buildings.
- amended approach to on-site generation of power (excludes exported power) and to connections to a heat network (focus on the performance of the building).
- support for planned introduction of the ‘New Build Heat Standard’ from 2024.
- updates to elemental standards for building fabric and services.
- more emphasis on commissioning and provision of information.
- action to improve energy performance through improved compliance with standards. ‘Compliance Plan’ approach - opportunity to pilot work on energy to reduce concern over ‘designed versus as-built’ performance gap.
- proposals for EV charging points and infrastructure in new buildings and those subject to ‘major renovation’ (now published, implementation from 5 June 2023).
- continuing discussions on standards beyond 2024 and the New Build Heat Standard.
Change to adopt SAP 10 & SBEM v6
- updated versions of the UK Calculation Methodologies for assessment of new buildings. SAP 10.2 (confirmed April 2022) and SBEM v6.1 (last updated April 2022).
- consultation versions of revised versions made available during 2021 – iSAP and c- SBEM (no longer available).
- final Scottish specifications confirmed and issued to BRE in April 2022. SAP specification will be issued to developers in Autumn, iSBEM and information for third party developers also available from August 2022.
- availability of software tools implementing Scottish changes has progressed, though not all tools have migrated to the new versions yet. BSD continue to engage with software providers to press on delivery of updated products.
Changes to Standard 6.1
- standard now sets both emission and energy targets for new buildings.
- new delivered energy target introduced. Delivered energy adopted as the metric as it represents the energy from external sources needed to meet building energy demand.
- the scope of the standard is unchanged for 2022, still applies only to new buildings on construction and to large non-domestic extensions. All fuels can still be used.
- the existing emissions target no longer applies to any new building that does not use ‘direct emissions heating systems’ – basically those that rely on combustion of fuel at the building to create heat.
- such solutions (definition added to Appendix A) will be excluded from 2024. The energy target provides a means of demonstrating compliance where ‘zero direct emissions’ heating systems are used - in advance of the proposed 2024 New Build Heat Standard.
6.1 - amended approach to target setting
- notional building (NB) specifications are revised to deliver an aggregate emission reduction of 32% for new homes and 20% for new non-domestic buildings.
- for new homes, now only three notional buildings, applied based upon main heating fuel choice – heat pump, heat network or any other fuel (6.1.2). NB specification is the same for each except heat generator specification and, for heat pump buildings, no on-site generation element is included (as heat pumps are already more effective in reducing energy demand and delivered energy totals).
- similar approach for new non-domestic buildings, plus space and water heating now assessed separately in the NB based upon the specification of the actual building. Plus amended guidance on shell/fit-out (6.1.8) and modular buildings (Annex 6.B).
- for new homes, the simplified approach is no longer available. Also, all new buildings must be assessed based upon their actual orientation (no default values).
6.1 - changes for on-site generation
- appendix M1 of SAP 10 now calculates the portions of on-site generation of power which are either used or exported to grid. In doing so, it will also model the benefit of a PV diverter switch (for hot water) or battery storage, but not both.
- with a focus on measures at the building which are effective in reducing delivered energy, we apply this new facility to exclude the export component from the 6.1 compliance calculation. This both provides a more representative illustration of the ‘at-building’ benefit of generation and also encourages on-site generation with storage. As energy exported from the building does not benefit the occupants.
- SBEM does not offer the same facility at present but a proxy of energy demand from ‘equipment’ (plug-in) load is used to similar effect, to define the extent to which on- site generation of power is useful in reducing delivered energy and emissions.
- the exported component is calculated and available for reporting, e.g. for the EPC.
6.1 - change for heat networks
- consultation proposed that performance of new buildings and performance of heat networks be regulated separately. The former through building regulations and the latter through pending regulations made under The Heat Network (Scotland) Act.
- this would standardise the approach for supplied heat connections to very energy efficient new buildings, irrespective of network characteristics. Treating a heat network like any other heat source with a declared efficiency.
- heat networks are a ‘zero direct emissions’ heat solution and therefore connected buildings no longer need to meet an emissions target, just the new energy target.
- consultation proposal offered a ‘direct electric work-around’ and comparison with the gas NB to deliver this. The final proposal is simpler, applying the HN specification to both notional and actual building but retains the benefit of 100% utilisation of supplied heat compared to a less efficient (mains gas boiler) notional building.
6.1 - supporting further change in 2024
Separate consultation last year proposed a New Build Heat Standard from 2024.
Implementation of the standard in 2024 would remove the option of current ‘at-building’ combustion solutions for new buildings. The 2022 standards support this intent through:
- the introduction of the delivered energy target as an ongoing performance metric;
- removing the emissions target where ‘direct emission heating’ is not used;
- simplifying compliance for new buildings connected to a heat network;
- requiring new buildings with direct emission heating systems to be designed for easy retrofit with a future ‘zero direct emissions’ heat solution; and
- setting standards for wet heating systems based upon lower distribution temperatures compatible with effective use of heat pumps and heat connections.
Standard 6.2 and building fabric
- improved ‘backstop’ U-values for elements of fabric (clause 6.2.1).
- values cited are from ‘improved’ standard consulted upon and represent elemental values of the best 50% of recent new construction.
- this single set of values is applied now to all new construction – newbuild, extension, alteration, conversion & shell. Alternative values for modular buildings (ND Annex 6.B).
- for new homes, alternative approach set out - use of a ‘space heating demand’ limit for new homes for more flexibility. Target set via SAP ‘box 99’ using NB specification with U-values replaced by those in table 6.2. This is then compared with the same calculated output for the actual building which should not exceed the demand limit.
- option of window/doorset energy ratings for elements fitted to existing buildings.
- thermal bridging at junctions – to note that no updated BSD construction detail sets are provided. But the current example details and psi values remain available for citation where representative of constructions.
6.1 - airtightness testing
- guidance on airtightness testing of new homes moves from sample testing to testing of all completed dwellings.
- reduced exceptions to the need to test for new non-domestic buildings.
- as in the rest of the UK, Scotland has moved to adopt CIBSE TM23 as the cited base methodology for airtightness testing. Similarly, the option to test using the newer ‘low pressure pulse’ method is now recognised.
- in consultation with verifiers and testing organisations, the supporting BSD airtightness document will be updated shortly to reflect these changes. Including consideration of process/options where testing cannot be completed.
- also develop discussions on opportunities to support compliance agenda, develop access to registered testers across Scotland (and remote/island areas in particular).
Standards 6.3 to 6.6 – Building Services
Building services compliance guides retained and updated. This format may be reviewed further for 2024 as significant support was received for reintegration into the Technical Handbooks.
Key changes, aside from revision of guidance on minimum system standards – D/ND:
- replacement of heat generator that involves a change in fuels should not result in an increase in building emissions or overall energy demand at the building.
- guidance on the need for space heating, domestic hot water and cooling systems to be sized appropriately.
- wet heating systems to be designed to enable effective operation at a low temperature (55 °C or lower).
- fitting of self-regulating devices (e.g. TRVs) to radiators/emitters if not already present when replacing heat generator.
Standards 6.3 to 6.6 – Building Services
Key changes aside from revision of guidance on minimum system standards – D/ND:
- simplified guidance on pipework insulation citing examples and reference to BS 5422.
- ventilation systems that provide mechanical supply and extract ventilation should be fitted with heat recovery, summer bypass and variable speed control where practical to do so.
- new section introduced for on-site electricity generating systems. Other key changes (Domestic only):
- additional energy efficiency measures to be introduced when a gas boiler is replaced.
- guidance on the maximum daily heat loss for hot water cylinders.
- commissioning plan to be confirmed at design stage with confirmation of commissioning provided on completion of the building.
Other key changes (Non-domestic only):
- air distribution systems - additional advice on controls, expanded advice on air leakage from ductwork and clarity on test procedures.
- advice on lighting design and avoidance of over-illumination.
- new section on Building Automation and Control Systems (BACS).
Documents present the same provisions as the rest of the UK with minor variations:
- slightly different text on design of heat distribution systems to operate effectively at low flow temperature, but same outcome sought.
- consequential improvement on replacement of gas boilers covers system and combi.
- non-domestic – new requirement for Building Automation and Control Systems. Threshold for new buildings is 290 kW (per EPBD). Lower in England.
Standard 6.6 - ventilation
- information on the new requirement for assessment and mitigation of overheating risk in new homes and similar residential non-domestic buildings is covered in a separate presentation on Section 3 (environment).
- guidance to standard 6.6 now refers to the overheating risk assessment applicable to new homes and new ND residential buildings. There is emphasis on the need to avoid active/mechanical cooling systems.
- the Domestic Handbook no longer makes reference to use of Appendix P of SAP which is withdrawn and no longer included in SAP 10.
- guidance on minimum system efficiency of ventilation and cooling systems is still addressed by reference to provisions within the two Building Services Compliance Guides.
Standard 6.7 - commissioning
Standard 6.7 is amended to explicitly include ‘control systems’ as a building service which must be commissioned and confirms that commissioning should also address the effective operation of installed services.
- guidance is introduced on the need to produce a commissioning plan at design stage, as part of the building warrant submission.
- guidance also identifies the need to provide a commissioning report on completion of construction. This should report on the actions identified in the commissioning plan and record any variation needed to that plan to reflect the as-constructed building and provide a copy of the outcome of the commissioning process for all the listed elements of building services.
- further work on reporting on commissioning is expected to be developed as part of the compliance plan approach for section 6 (energy) – see below.
Standard 6.8 - written information
Guidance is extended to cover written information on managing overheating risk and on how building can be retrofitted with a ‘zero direct emissions’ heat source.
- guidance on the provision of a ‘quick start’ guide for all new homes is updated to include information on avoiding overheating risk, drawing on information identified in guidance to new standard 3.28.
- new guidance is introduced setting out provisions for information to support retrofit of any non-direct emission heating systems fitted as part of a new building. This information is to provide assurance to the building owner that the future replacement of a combustion appliance with a ‘zero direct emissions’ alternative was considered at design stage. And that the configuration of the initial heat generator, distribution system and the building layout will enable simple replacement of the combustion appliance without significant additional cost or disruption.
Standard 7.1 – Aspect 1 (emissions)
Sustainability labelling of new buildings includes optional levels of emission performance which improve on those set under standard 6.1 as a result of the improved standard 6.1 compliance targets, the minimum level at which this aspect is assigned for compliance with the 2022 standard is re-evaluated.
- new dwellings that meet the 2022 Target Emissions Rate (TER) or, where TER is not calculated, the Target Delivered Energy Rate (TDER) will be deemed to meet the Gold level criteria in respect of emissions. This level is assigned as the 2022 standards deliver a 46% improvement on 2010 standards which define the levels of this aspect.
- new non-domestic buildings will continue to be deemed to meet the Silver level criteria in respect of emissions as the 2022 standards deliver a 54% improvement on 2010 standards. To achieve Gold under SBEM v6, the 2022 TER (or TDER if no TER) should be multiplied by 0.8, to give a target which the BER (or BDER) should not exceed.
Onward work – compliance manual
- as part of our consultation last year, we sought views on how compliance with the energy aspects of building design could be improved. The intent being to identify and collate current industry good practice on this issue, with evidence of what works.
- it was proposed that a ‘compliance manual’ for section 6 would be developed to form part of the ‘compliance plan’ approach to design and construction also being consulted upon by Building Standards Division.
- that work is ongoing, supported by the commentary and evidence provided in consultation responses. We have commissioned an initial proposal through ‘Built Environment - Smarter Transformation’ (previously the Construction Scotland Innovation Centre). That report is expected in spring 2023 and will support ongoing review work, including the recent announcement on a ‘Scottish equivalent to the Passivhaus standard’ for 2024/25.
- a timetable and approach for development of a guide for good practice in the design and construction of very low energy buildings is an intended output of this process.
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Building Standards page on gov.scot
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